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261 Pages·2010·3.31 MB·English

Sunday Afternoon, October 17, 2010
Biomaterials Plenary Session The coming decade is without becoming the decade of effective
antimicrobial coatings for biomedical implants and devices. Societal
Room: Taos - Session BP-SuA
pressure is huge and with the current developments of new evaluations
technologies and better insights in the different functionalities with which
Detecting, Characterizing and Controlling Biofouling effective coatings should be equipped, clinical breakthrough should be
within reach.
Moderator: S.L. McArthur, Swinburne University of
Technology, Australia
4:20pm BP-SuA5 Engineered Surface Designs for Directed
Attachment on Topographies, A.B. Brennan, C.M. Magin, University of
3:00pm BP-SuA1 The Effect of a Polymer Brush Coating on Protein Florida, L.K. Ista, University of New Mexico, G.P. Lopez, Duke University,
Adsorption, Bacterial Adhesion, and Biofilm Formation, W. Norde, M.E. Callow, J.A. Finlay, J.A. Callow, University of Birmingham, UK
Wageningen University, University Medical Center Groningen and INVITED
University of Groningen, the Netherlands INVITED Biofouling is a technically complex issue that directly impacts our
Adsorption of proteins from biofluids is considered to be the first event in economic stability and environmental health. Recent identification of the
the biofouling process. Subsequently, micro-organisms and/or biological long term negative effects of chemical antifouling compounds led to a
cells (e.g. blood platelets, erythrocytes) adhere to the surface and a biofilm world ban of TBT in 2008. We are investigating the impact of
may be developed. In this paper, generic principles of the interaction physical/chemical characteristics of surfaces on the attachment process. Our
between a polymer brush and indwelling particles (globular proteins; micro- focus on topography led to the development of the Sharklet AF™ pattern,
organisms) are explained and illustrated with some experimental results. which is a bio-inspired structure embossed into polymeric surfaces. The
Furthermore, the influence of a polymer brush on the development and Sharklet AF™ pattern was the first example of a physical attribute capable
characterization of a biofilm is discussed. of strongly inhibiting the attachment of the zoospore of Ulva green algae
and the cells of Cobetia marina bacteria. Amodel is presented for bacteria
and algal zoospores, correlating attachment density with surface roughness.
3:40pm BP-SuA3 Biomaterials-Associated Infections – In Vitro and In
Our model demonstrates, for the first time, that organisms respond in a
Vivo Studies, H. Busscher, University Medical Center and University of
Groningen, the Netherlands INVITED uniform manner that can be described in terms of surface energy and a
Reynolds number associated with the organism.
Modern health care is greatly dependent on the use of biomaterials implants
and devices for the restoration of function, after trauma, (oncological)
intervention surgery or simply wear due to old age. Biomaterials implants
surfaces in the human body are prone to infection, as can develop through
three distinctly different routes. Peri-operative infection is the best
documented route and usually causes early infection of an implant. Also
immediate post-operative infection can be a cause of early failure. Late
post-operative infections spreading from infections elsewhere in the body
have also been described to be a cause for implant infection and failure.
Since a biomaterial-associated infection (BAI) is difficult to treat with
antibiotics due to the protection offered by the biofilm mode of growth and
intra-cellular shelter, the fate of an infected implant often is removal, at
great discomfort to the patient and costs to the healthcare system.
Frequently even, the condition of a patient does not allow replacement
surgery or removal of a device. BAI can be lethal when spreading through
the body. Whereas the infection rate of primary implants may be considered
low (4-6% on average depending on the implant type), infection rates in
revision surgery are much higher around 15%.
Prevention strategies under investigation are numerous, but no generally
effective way to prevent BAI has been found. Moreover, prevention of BAI
of a primary implant may require different approaches than the prevention
of BAI of secondary implants after treatment of BAI.
Numerous prevention strategies based on biomaterials surface modification
that discourage microbial adhesion and biofilm formation have been
forwarded in the literature, but none of them have clinically provided a
breakthrough. The lack of a clinical breakthrough is partially due to the low
incidences of BAI (though still being unacceptably high), requiring large
numbers of patients to be enrolled in a study. Therefore, novel evaluation
technologies are required that indicate whether new preventive strategies
work under in vivo conditions.
Bioluminescence and Fluorescent Imaging are new evaluation technologies
(BLI and FLI) that offer the opportunity to observe the in vivo course of
BAI in small animals without the need to sacrifice animals at different time
points after the onset of infection. BLI is highly dependent on the bacterial
cell metabolism which makes BLI a strong reporter of viable bacterial
presence. Fluorescent sources are generally more stable than bioluminescent
ones and specifically targeted, which renders the combination of BLI and
FLI a promising tool for imaging BAI.
In the concept of the race for the surface, successful implant coatings should
favour tissue integration over microbial colonization. This suggests that
new prevention strategies abandoning the concept of mono-functional fully
non-adhesive, tissue-supporting, or immune-friendly coatings may have to
be developed on the basis of multi-functional coatings better mimicking
natural tissue. The efficacy of macrophages in removing adhering bacteria
from a surface for instance, is much higher on cross-linked PEG coatings
than on glass because bacteria do not switch on their natural defences on
such highly hydrated coatings exerting only weak interaction forces, while
macrophages are less immobilized for the same reasons. Polymer brush
coatings, designed with an occasional RGD-group for instance, keep their
non-adhesive functionality, while at the same time supporting tissue
integration.
1 Sunday Afternoon, October 17, 2010
Monday Morning, October 18, 2010
Actinides and Rare Earths Topical Conference electron spectroscopy ( AES ), provides a controlled environment ideally
suited to study the behavior of gallium during the initial stages of Pu/Ga
Room: Isleta - Session AC+SS-MoM
oxidation. In addition to information about the oxidation states of the
plutonium species in the near surface region provided by XPS, both XPS
Surface Science of Actinides and AES are very useful for studying the relative atomic concentration of
elements present at the sample surface (such as oxygen and gallium). While
Moderator: J.G. Tobin, Lawrence Livermore National
these surface sensitive techniques suffer from relatively high limits of
Laboratory detection, we have been able to qualitatively, and in some cases
quantitatively, study the behavior of gallium during the oxidation of the δ-
plutonium alloy. The gallium content relative to plutonium is observed to
9:00am AC+SS-MoM3 High Resolution Auger Electron Spectroscopy
decrease within the oxide film during oxidation, with the displaced gallium
of Plutonium Metal and Oxide Surfaces, D.P. Moore, A.L. Broach, D.L.
apparently moving to the oxide/metal interface to form a thin gallium rich
Pugmire, Los Alamos National Laboratory, H.G. Garcia Flores, Univeristy
of Nebraska-Lincoln, P. Roussel, Atomic Weapons Establishment region. The results of these studies and their implications on the mechanism
of gallium-stabilized, δ-plutonium oxidation will be discussed.
There has been considerable new study of the oxidation of plutonium in
recent years. Much of this study has focused on the properties of the thin
film oxide layers that form on the plutonium metal surface under exposure 9:40am AC+SS-MoM5 Angle-Resolved Photoemission and the 5f
to oxygen. For these studies, x-ray photoelectron spectroscopy (XPS) has Electronic Structure of Pu Materials, J. Joyce, T. Durakiewicz, K.S.
typically been the technique of choice as it is ideally suited for the study of Graham, E.D. Bauer, J.N. Mitchell, D.P. Moore, J.A. Kennison, T.M.
oxidation states by analyzing XP peak shape and position changes. This McCleskey, A.K. Burrell, E. Bauer, Q. Jia, Los Alamos National Laboratory
allows for the identification of relative changes in the Pu 4f manifold in INVITED
going from Pu metal, to the Pu sesquioxide (PuO), to the Pu dioxide The electronic structure of Pu compounds ranging from Mott insulators to
2 3
(PuO). But there are advantages of other surface science techniques, strongly correlated metals is investigated using angle-resolved
2
specifically Auger electron spectroscopy (AES), over XPS for certain types photoemission (ARPES). The electronic properties of the Pu compounds
of studies. Prime among them is that AES has a much higher spatial PuCoGa5, PuSb2, and PuO2 are compared with angle-integrated and
resolution than XPS allowing for analysis of specific areas and features on a temperature-dependent photoemission results for Pu metal. The balance in
surface down to a few tens of nanometers. And although AES typically strongly correlated materials between the central and periodic potentials is
suffers from less sensitivity and specificity to chemical state differences in directly probed through ARPES. For the strongly correlated metals, details
its peak shape and position, modern Auger systems with field emission of the sharp quasiparticle peak at the Fermi energy are presented, including
sources and hemispherical electron analyzers have alleviated much of this crystal momentum dispersion, giving insight into the self-energy and
shortcoming. ground state properties of these Pu materials. In PuSb2, the ARPES data at
a photon energy of 21.2 eV, indicates a quasiparticle peak that disperses
For plutonium, Auger peaks for the metal and dioxide have been used for
through the Fermi energy. At 40.8 eV photon energy, PuSb2 shows f-
investigation whereas the Auger peaks for the sesquioxide have not
electron intensity periodic with the lattice. Photoemission results for the
received the same study. Peak positions from derivative spectra have been
Fermi level spectral intensity as well as the more localized 5f states well-
used for distinguishing between metal and oxide with quantification of the
removed from the Fermi energy are used to quantify adaptive character for
oxides from peak-to-peak heights and estimates of relative sensitivity
these materials. Both PuSb2 and PuCoGa5 ARPES data show a dispersive
factors. In order to more fully utilize AES for the study of the oxidation of
peak which crosses the Fermi energy at a photon energy of 21.2 eV where
plutonium surfaces, the relative changes in the Auger peaks in going from
the conduction states have a larger cross section than the 5f states. The
Pu metal to all its oxides must be quantified. We have used high resolution
results for 40.8 eV photon energy, with enhanced 5f strength, indicate a
AES to identify the Auger peak structure of Pu metal, PuO, and PuO. We
2 2 3 peak dispersing through the Fermi energy for PuCoGa5 but the PuSb2 data
have studied the OPP and OVV Auger transitions in the 80 – 110 eV range
indicate an intensity modulated peak near the Fermi energy. The first
as well as the NOV transitions at approximately 315 eV via oxygen dosing
ARPES results for the Mott insulator PuO2 show substantial dispersion
on Pu metal surfaces. Oxygen doses from less than a Langmuir up to over
consistent with hybrid functional calculations which predict significant
500 Langmuirs have been investigated. Relative changes in both the
covalency for PuO2 compared with the earlier ionic actinide dioxides such
integrated and derivative Auger peak structures for Pu metal, PuO, and
2 as UO2. The ARPES, photon energy dependence, and the temperature
PuO have been identified and will be presented. Using this new
2 3 dependent data for Pu materials will be discussed in terms of 5f adaptive
information we will be able to take advantage of the higher spatial
character and the implications for Pu ground state properties.
resolution of AES to further study plutonium oxide properties such as layer
structure, oxidation kinetics, and auto reduction on polycrystalline
plutonium samples.
Work supported by the U.S. Department of Energy, Basic Energy Sciences,
the Los Alamos National Laboratory LDRD program, and Campaign II.
9:20am AC+SS-MoM4 The Behavior of Gallium During the Initial
Stages of Plutonium/Gallium Alloy Oxidation, D.L. Pugmire, Los
10:40am AC+SS-MoM8 Novel Band Renormalization Mechanism in f-
Alamos National Laboratory, H.G. Garcia Flores, University of Nebraska-
electron Systems, T. Durakiewicz, J. Joyce, Los Alamos National
Lincoln, D.P. Moore, A.L. Broach, Los Alamos National Laboratory, P.
Laboratory, P.S. Riseborough, Temple University, P.M. Oppeneer, Uppsala
Roussel, Atomic Weapons Establishment
University, Sweden, J.-C. Griveau, ITU, Germany, E.D. Bauer, Los
An area of significant importance to the oxidation of any alloy is the role Alamos National Laboratory, E. Guziewicz, Polish Academy of Sciences,
that the constituent metals play. It has been previously shown that the Poland
oxidation rate for the δ-phase stabilized, plutonium/gallium alloy can be
Several mechanisms may lead to band renormalization in strongly
significantly affected by the gallium content as well as composition of the
correlated systems. Inter-band scattering was recently shown to produce
oxidizing atmosphere (O2, O2/H2O, H2O). Reasons for the observed rate significant renormalization effects in high temperature superconductors.
changes upon alloying with gallium are not understood. A previous study of Here we show, for the first time, that inter-band processes may lead to
a variety of δ-plutonium alloys shows that the significant structure strong band renormalization in the vicinity of Fermi level in a 5f-electron
difference between unalloyed α-plutonium and alloyed δ-plutonium cannot system, USb. The Fermi surface of this compound consists of several
be the sole cause of different oxidation rates. This implies that the alloying 2
uniaxial cylindrical sheets. We show that the bare band LDA calculation
metal must play some role in the slower oxidation rates observed for
over-counts the number of sheets, because it lacks the renormalization part.
gallium-stabilized δ-plutonium. In order to elucidate the oxidation
But our high resolution angle resolved photoemission (ARPES)
mechanism of this commonly employed alloy, it is important to understand
experiments demonstrate that one of the calculated cylinders shrinks below
the role gallium plays during oxidation. The relatively low concentrations of
the Fermi level, forming a closed cigar-shaped Fermi surface rather than an
alloying metals used, typically several atomic percent, can make the
open cylindrical one. In normal emission experiments, we measure the
activities of gallium during oxidation of δ-plutonium difficult to follow.
dispersion of the bands of interest in the Gamma-Z direction. The measured
This complication is compounded by the fact that the initial stages of
results disagree with the LDA result, but the bare LDA bands can be
oxidation are inherently a surface phenomenon, thereby significantly
renormalized by using a low order self-energy expansion in three-band
limiting the relative amount of affected material. Significant questions
inter-band scattering model, and very good fit is obtained. We conclude that
remain as to what is a realistic description for the Pu/Ga-oxide, thin-film
inter-band scattering in USb influences the fermiology of this system in
system during the initial stages of oxidation. 2
terms of changing the shape and number of Fermi sheets.
An ultra-high vacuum (UHV) system equipped with surface sensitive
techniques, such as x-ray photoelectron spectroscopy (XPS) and Auger
Monday Morning, October 18, 2010 2
11:00am AC+SS-MoM9 The Initial Oxidation of Polycrystalline substrate placed perpendicular to the electrodes depend on the distance from
Thorium, M. Bagge-Hansen, R.A. Outlaw, D.M. Manos, College of the discharges [1-4]. Thus, we can simultaneously deposit Si thin films with
William & Mary various structures and properties. For 60 MHz discharges of H+SiH
2 4
The initial oxidation of clean, polycrystalline α-Th from background (0.3%), no films were deposited just near the discharge regions due to Si
CO/CO and saturation of the Th surface by O has been examined in etching by H, micro-crystalline films were deposited in a rather narrow area
2 2
ultrahigh vacuum (p < 2x10-11 Torr, H) by angle resolved Auger electron around the no film regions, and a-Si:H films were obtained in the rest wide
2
spectroscopy (ARAES) and time of flight secondary ion mass spectrometry area far from the discharges. The spatial distribution of film structures
(ToF-SIMS). Following dissociative adsorption of background CO/CO2, the indicate that the density ratio of H to SiH3 decreases sharply with increasing
accompanying oxygen surface population increased at a rate roughly one the distance from the discharges and the surface reaction probability of H is
third that of the carbon, suggesting significant oxygen incorporation into the much higher than that of SiH3, being consistent with the reported surface
bulk. The admission of O following heating and sputter cleaning of the Th, reaction probabilities [5, 6]. For 2-6 Torr, the micro-crystalline film
2,
showed similar behavior in that some oxygen atoms continued to diffuse structure such as crystalline volume fraction and grain size varies sharply
into the bulk until formation of stoichiometric ThO was observed at ~37 L. not only along the direction perpendicular to the electrodes but also along
2
The thickness of the oxide complex was determined by both ARAES and the direction parallel to the electrodes. These results suggest that the micro-
ToF-SIMS and found to be ~5 nm. The thermal stability of the ThO over crystalline film structure is highly sensitive to spatial and temporal
2
the temperature range of 25 – 1000°C was also studied. Rapid uniformity of fluxes of H and SiH3 as well as their flux ratio.
decomposition of the oxide by CO desorption and subsequent oxygen [1] K. Koga, et al., Jpn. J. Appl. Phys. 44, L1430 (2005).
dissolution into the bulk was observed to occur within a temperature range
[2] W. M. Nakamura, et al., IEEE Trans. Plasma Sci. 36, 888 (2008).
of ~550-750°C.
[3] W. M. Nakamura, et al., J. Phys.: Conf. Series 100, 082018 (2008).
11:20am AC+SS-MoM10 The Non-Equilibrium Nature of Uranium [4] H. Sato, et al., J. Plasma Fusion Res. SERIES, 8, 1435 (2009).
Oxide Surfaces, R.K. Schulze, D.P. Johnson, M.A. Hill, Los Alamos [5] A. Matsuda, et al., Surface Sci. 227, 50 (1990).
National Laboratory
[6] J. Perrin, et al., J. Vac. Sci. Technol. A, 16, 278 (1998).
We examine the surface reactions of bulk single crystal uranium oxide
(UO) and thin films of uranium oxide on metal using Kelvin probe (surface
2
work function and chemical potential) measurements and x-ray and 8:40am EN+PS-MoM2 Infrared Solar Cells Using Plasma-Processed
ultraviolet photoelectron spectroscopy. The processes of surface and sub- Carbon Nanotubes, T. Kaneko, S. Kodama, Y. Li, R. Hatakeyama, Tohoku
surface reactions with small gas phase molecules are examined through in- University, Japan
situ work function measurements (dynamic) while the surface chemistry Since the conventional silicon solar-cell conversion is limited to a certain
and configuration are probed with photoemission and LEED measurements window of solar cell photon energies over 1 eV, a full use of the solar
(equilibrium). The hyperstoichiometric uranium oxide (UO ) is shown to spectrum is one of the crucial issues in order to greatly increase the solar
2+x
be composed of, in the surface region, labile interstitial oxygen that can be cell efficiency. In this sense, carbon nanotubes (CNTs) are attracting much
moved relatively easily in and out of the fluorite structure lattice through interest for photovoltaic energy conversion because of their broad
control of the headspace oxygen activity. The transport of oxygen in this absorption bands including the infrared range (0.2 ~ 1.3 eV) as well as other
near surface region of the oxide is examined through changes in the surface advantages such as large surface areas, high mobility of charge carrier, high
work function with exposure to various partial pressures of oxygen. The mechanical strength, chemical stability, and so on. In this connection, we
amount of excess oxygen in the oxide lattice of the surface is shown to have developed a plasma-ion irradiation method, which enables pristine
affect the reactivity of this surface with small gas phase molecules directly. single-walled carbon nanotubes (SWNTs) to selectively encapsulate various
A measurement and description of the band structure of the uranium oxide kinds of atoms and molecules, such as metals and fullerenes, serving as
surface for different levels of oxygen content (UO, UO , UO, UO ) is electrons donors or acceptors inside their cavities. Then these enhanced p-
3 2+x 2 2-x
presented. type, n-type, and pn-junction housed semiconductor-SWNTs are applied
toward the realization of high-efficient photovoltaic devices, which is
composed of thin films of p- and n-types semiconductor SWNTs or an
11:40am AC+SS-MoM11 Characterization of the Surface Changes
individual SWNT with p-n junction inside. Here, as a first step, electrical
During the Activation of Erbium/Erbium Oxide for Hydrogen Storage,
properties of p-n junctions fabricated using a combination of the thin films
M.T. Brumbach, K.R. Zavadil, C.S. Snow, J.A. Ohlhausen, Sandia National
of pristine (empty) SWNT or C -encapsulated SWNT (C @SWNT), and
Laboratories 60 60
n-doped Si (n-Si) are investigated.
Erbium is known to effectively load with hydrogen when held at high
temperature in a hydrogen atmosphere. To make the storage of hydrogen The electrical properties of these SWNT film/n-Si devices show an obvious
kinetically feasible, a thermal activation step is required. Activation is a rectifying characteristic, and a short-circuit current ISC and an open-circuit
routine practice, but very little is known about the physical, chemical, voltage VOC through a downward shift of I-V curves are observed under
and/or electronic processes that occur during Activation. This work presents illumination of light with wavelength of 1550 nm which corresponds to the
in situ characterization of erbium Activation using variable energy photon energy of 0.8 eV. Moreover, it is found that the device fabricated
photoelectron spectroscopy at various stages of the Activation process. with the C60@SWNT film has a larger VOC caused possibly by a large
Modification of the passive surface oxide plays a significant role in diffusion voltage in the interface of p-n junction compared with the device
Activation. The chemical and electronic changes observed from core-level fabricated with the pristine SWNT film, due to the enhanced p-type
and valence band spectra will be discussed along with corroborating ion behavior of SWNTs after C60 encapsulation. To investigate undesirable
scattering spectroscopy measurements. photovoltaic effects of n-Si, we fabricate a schottky barrier solar cell
consisting of silver (Ag) and n-Si in the absence of SWNTs. It is confirmed
§Sandia National Laboratories is a multi-program laboratory operated by
that the Ag/n-Si schottky barrier solar cell generates photo currents in the
Sandia Corporation, a wholly owned subsidiary of Lockheed Martin
visible range (1.5 ~ 3 eV), while there is almost no difference between with
Company, for the U.S. Department of Energy’s National Nuclear Security
and without light in the infrared range (0.8 eV) because the light with
Administration under contract DE-AC04-94AL85000.
photon energy less than 1 eV cannot be absorbed by Si.
Based on these results, high performance solar cells which work in the
infrared region are for the first time demonstrated to be formed using
Energy Frontiers Topical Conference
SWNTs, especially p-type enhanced C @SWNT.
60
Room: Mesilla - Session EN+PS-MoM
9:00am EN+PS-MoM3 A Novel Method of Controlling Plasma
Plasmas for Photovoltaics & Energy Applications Uniformity in a Large Area VHF Plasma Source for Solar
Applications, T. Tanaka, J. Kudela, E. Hammond, C. Boitnott, Z. Chen,
Moderator: B. Lane, TEL Technology Center America
J.A. Kenney, S. Rauf, Applied Materials Inc. INVITED
Processing a large area substrate in a capacitively coupled plasma (CCP)
8:20am EN+PS-MoM1 Combinatorial Plasma CVD of Si Thin Films reactor is becoming increasingly more difficult as the driving frequency
with a Multihollow Discharge Plasma CVD Reactor, M. Shiratani, K. required by the process is becoming higher and the size of the substrates is
Koga, T. Matsunaga, Y. Kawashima, W. Nakamura, G. Uchida, N. Itagaki, becoming larger. At the VHF (very high frequency) range the wave length
Kyushu University, Japan of the driving signal is approaching the size of the substrate, and the
A-Si and micro-crystalline thin films for solar cells are widely deposited by resulting standing wave causes a severely non-uniform process. In this
plasma CVD in industry. To realize combinatorial plasma CVD of such Si presentation, we will present a novel approach using magnetic boundary
thin films, we have developed a multi-hollow discharge plasma CVD conditions in conjunction with phase modulation between multiple power
method, by which fluxes of H and SiH as well as their flux ratio on the feed points to improve process uniformity for a CCP reactor operating in
3
the VHF range. The substrate size we consider is Gen 8.5 (2.2 m × 2.6 m
3 Monday Morning, October 18, 2010
substrate) and the VHF power applied to generate the plasma is 40 and 60 power range of 5 to 40 W. The in situ IR data show that the surface hydride
MHz. At 60 MHz, with the vacuum wavelength of 5 m, the size of the composition of the NPs is related to their crystallinity, which in turn
substrate is approximately ½ of the vacuum wavelength. An depends on particle heating during synthesis. The as-synthesized NPs
electromagnetic simulation with a pseudo plasma showed that, when 60 surfaces are terminated with Si mono-, di- and tri-hydrides. The higher
MHz is applied in a conventional manner, i.e. it is fed from the center of the hydride concentration decreases with increasing particle crystallinity,
back of one of the electrodes, it generates a dome shape electromagnetic similar to previous observations on the amorphous Si surfaces, where higher
field profile, which falls off sharply to almost zero at the voltage node Si hydrides are known to decompose with increasing deposition
before rising again towards the edges. A similar field pattern was also temperatures. These results also are consistent with the particle heating
generated even when the VHF was fed from two feed points located at the models proposed for dusty plasmas. In the first surface passivation
opposing edges. The plasma distribution pattern measured with a 4 × 8 grid approach, the as-synthesized H-terminated Si NPs, which oxidize even
of optical emission spectroscopic (OES) probes revealed that the plasma under high-vacuum conditions, are passivated in situ through
was localized in the center when VHF the signal applied to the feed points hydrosilylation using 1-alkenes of different chain lengths. We have used
were in phase. To modify the wave propagation pattern to change the shape density functional theory calculations to investigate the detailed reaction
of the standing wave in the central area, we placed ferrite material along mechanism for various alkene chain lengths, and to understand the effects
two of the edges (edges that are away from the feed points) of the powered of alkene coverage on the oxidation of the surface. The surface reaction
electrode. In this case, the peak in the central area was significantly kinetics for hydrosilylation is observed in situ by monitoring the C-H and
stretched towards the ferrite-lined edges. We also found that the stretched Si-H stretching vibrations. The ligand coverage is determined to be roughly
“bar” of plasma could be moved over the substrate area by dynamically 50% of the surface sites, which is sufficient to prevent oxidation for several
modifying the relative phase between the feed points in a manner similar to hours. The quality of surface passivation is further determined through the
the technique employed by Yamakoshi etal. [1], and effectively distribute photoluminescence quantum yield measurements, which show a higher
the processing plasma to much larger area. yield for surface passivated NPs. In the second approach, the NPs are
passivated with metal oxides using atomic layer deposition that involves the
[1] H.Yamakoshi etal. Appl. Phys. Lett. 88, 081502 (2006)
two different oxidation steps with O and HO to achieve deposition at <200
3 2
°C.
9:40am EN+PS-MoM5 Novel Plasma Processing Routes of Si
Nanocrystals for Photovoltaic Applications, İ. Doğan, N.J. Kramer, MA.
Verheijen, Eindhoven University of Technology, Netherlands, T.H. van der 11:20am EN+PS-MoM10 Effects of Hole-Array-Electrode on the
Loop, University of Amsterdam, Netherlands, A.H.M. Smets, Eindhoven Characteristics of Radio Frequency Capacitively Coupled Plasma
University of Technology, Netherlands, T. Gregorkiewicz, University of Sources for uc-Si Thin Film PECVD, H.-J. Lee, S.-S. Wi, Pusan National
Amsterdam, Netherlands, M.C.M. van de Sanden, Eindhoven University of University, Republic of Korea, D. Kim, D. Hwang, W.S. Chang, LG
Technology, Netherlands Electronics, Republic of Korea
In order to improve the productivity of thin film growth in rf capacitively
coupled plasma based chemical vapor deposition system, modifications of
10:00am EN+PS-MoM6 Characterisation of Thin Film CdTe
electrode surface geometry has frequently been used. Array of holes in the
Multilayer Photovoltaic Devices Deposited by Closed Field Magnetron
shower head electrode is probably the most popular one. In this paper, using
Sputtering, J.K. Bowers, S. Moh, A. Abbas, P.N. Rowley, H.M. Upadhyaya,
self-consistent fluid approximation with collisional sheath model, we have
J.M. Walls, Loughborough University, UK
analyzed the effects of the hole array on the plasma characteristics in terms
A new magnetron sputtering strategy is introduced that utilises high plasma
of plasma density, electron temperature, ion current density, sheath voltage
densities (~5mA.cm-2) to avoid or reduce high temperature processing. The and electron heating efficiency. It is shown that electron heating efficiency
technique uses magnetrons of opposing magnetic polarity to create a of the hole array electrode increases more than 10 % compared with that of
“closed field” in which the plasma density is enhanced without the need for flat electrodes. DC bias voltage at the substrate side increases with hole
high applied voltages. A batch system has been used which employs a depth and pitch due to increase in surface area ratio between powered and
rotating vertical drum as the substrate carrier and a symmetrical array of substrate electrode. Peak electron density near throat region of the hole
four linear magnetrons. The magnetrons are fitted with target materials for structure becomes more than 2 time higher than that of flat parallel
each of the thin films required in the photovoltaic (PV) stack viz. CdTe electrode at the same voltage driving condition. It was experimentally
absorber layer, CdS buffer layer, metal contact and the back transparent verified that these variations of plasma properties is beneficial for high rate
conducting oxide (TCO) contact using the superstrate configuration. The of Si thin film deposition
“closed field” sputtering technology allows scale up not only for larger
batch system designs but it is also configurable for “in-line” or “roll to roll”
11:40am EN+PS-MoM11 Arc Energy in Large Scale Magnetron
formats for large scale production. The morphology of each of the layers is
Sputtering, D. Carter, H. Walde, Advanced Energy Industries, Inc.
characterised together with the overall device performance.
A detailed analysis of sputtering arcs on a large scale (3400 cm2) magnetron
source reveals some common trends related to energy absorbed in these
10:40am EN+PS-MoM8 Material Properties of Hydrogenated
events and the progression of current and voltage through their duration.
Nanocrystalline Silicon Thin Films by RF-PECVD using He-SiH
4 Examination of these trends provides insight into the rapid release of arc
Mixture, I.K. Kim, J.H. Lim, K.N. Kim, G.Y. Yeom, Sungkyunkwan
energy and some of the practical limitations of the techniques used to
University, Republic of Korea
minimize their impact on deposition processes. Two very different but
equally important materials were studied, metallic aluminum and ceramic,
11:00am EN+PS-MoM9 Surface Composition and Gas-Phase aluminum-doped, zinc oxide. While the characteristics and behaviors of
Passivation of Plasma-Synthesized Si Nanoparticles, B.N. Jariwala*, arcs from these two materials are generally similar, subtle distinctions in the
Colorado School of Mines, N.J. Kramer, Eindhoven University of evolution of current and voltage explain a significant difference in measured
Technology, Netherlands, B.G. Lee, P. Stradins, National Renewable arc energies. These observations present factors for consideration regarding
Energy Laboratory, M.C.M. van de Sanden, Eindhoven University of arc suppression and also raise the question of what is the minimum
Technology, Netherlands, C.V. Ciobanu, S. Agarwal, Colorado School of achievable arc energy. In an attempt to answer this fundamental question a
Mines stored energy model for a large scale magnetron system is proposed. Using
Tunable band gap of c-Si nanoparticles (NPs) (<5 nm) along with the practical assumptions for sheath capacitance and source inductance,
possibility of multiple exciton generation has led to an increased interest in minimum arc energy is calculated to serve as the ultimate goal for a next
this form of Si as a material for 3rd generation photovoltaic (PV) devices. generation arc detection and suppression system.
In addition to a high degree of control over the particle size, surface
passivation of the NPs is key to their utilization in PV applications. In this
presentation, we will primarily focus on understanding the growth of Si NPs
in a dusty plasma, determining the surface composition of the NPs, and
demonstrating novel techniques for passivation and encapsulation through
the gas-phase. The particles are grown in a SiH/Ar plasma generated in a
4
tubular flow rf discharge. The plasma source is attached to an in-house-built
vacuum chamber equipped with in situ attenuated total reflection Fourier-
transform infrared (ATR-FTIR) spectroscopy and a quadrupole mass
spectrometer. Using this technique, we have synthesized Si NPs in the size
range of 3-7 nm, which transition from amorphous to crystalline over the rf

* Coburn & Winters Student Award Finalist
Monday Morning, October 18, 2010 4
Graphene Focus Topic 9:00am GR+SS+TF+EM-MoM3 Epitaxial Graphene on SiC(0001), T.
Seyller, Universität Erlangen, Germany INVITED
Room: Brazos - Session GR+SS+TF+EM-MoM
The properties of graphene, its fabrication, and its application are very
active fields of research. The large carrier mobility and prospects for room-
Epitaxial Graphene on SiC temperature ballistic transport raise hopes for application of graphene in
Moderator: P.E. Sheehan, Naval Research Laboratory electronic devices. Applications, however, demand growth methods suitable
for producing graphene layers on a wafer scale. While this goal is
impossible to reach with mechanical exfoliation, epitaxial graphene (EG)
8:20am GR+SS+TF+EM-MoM1 Controlling Carriers in Graphene, grown on the basal plane surfaces of silicon carbide (SiC) offers a much
G.G. Jernigan, P.E. Thompson, C.S. Hellberg, J.L. Tedesco, V.D. Wheeler, better prospective. In this talk I shall review studies of the structural,
L.O. Nyakiti, P.M. Campbell, D.K. Gaskill, Naval Research Laboratory electronic, and transport properties of EG grown on SiC by solid-state
No technique for graphene synthesis yields controllably doped material. decomposition at elevated temperatures. The first part describes a study of
Measurements of carrier density and carrier type produce results that are the electronic structure and structural properties of EG which can
dependent on extrinsic factors. For example, exfoliated graphene and metal- conveniently be determined using surface science techniques. In the second
catalyzed graphene on SiO2 often obtain carriers through unwanted charges part I demonstrate how the growth of EG is improved by going from the
in the oxide[1] or by gas adsorption[2] making graphene p-type. Similarly, traditional growth environment, namely ultrahigh vacuum, to an Argon
epitaxial graphene on SiC should be n-type due to work function differences atmosphere. The latter method leads to vastly improved EG films with
with the underlying SiC substrate[3]. Our recent measurements of graphene properties similar to those of exfoliated graphene. Finally I shall discuss
grown on Si-face SiC show that device processing steps can cause it to how the interface between SiC and graphene can be controlled by
switch between carrier types. Additionally, we have found graphene grown intercalation of foreign atoms.
on C-face SiC to be highly doped by Si impurities, which can produce
either electrons or holes. 9:40am GR+SS+TF+EM-MoM5 Structural Defects in Epitaxial
We have begun a series of investigations to impart properties after growth Graphene Layers Synthesized on 4H-SiC(000-1) Substrate -
on epitaxial graphene formed on Si- and C-face SiC[4-5]. Substitutional Transmission Electron Microscopy (TEM) Studies, J. Borysiuk,
incorporation of impurity atoms can lead to doping in a graphene sheet, if University of Warsaw, Poland, S.K. Krukowski, Polish Academy of
their concentration does not drastically affect the pi-network. This can be Sciences, Poland
achieved by selective oxidation to remove C atoms from the graphene Main structural defects in graphene layers, synthesized on the carbon-
lattice and by molecular beam deposition (MBE) of dopants with terminated face, i.e. SiC(0001) face of 4H-SiC substrate, are discussed. The
controllable ultra-low fluxes to fill the C vacancies. It is important to note discussed structures include in-plane edge dislocations, grain boundaries,
that Group III and V dopants can maintain the 2D geometry of the graphene puckers, etc. These defects are investigated using High Resolution
sheet without producing an unsaturated bond (as they do when incorporated Transmission Electron Microscopy (HRTEM), revealing their atomic
into the bulk of Si.) Thus, the extra p-orbital electrons from the Group V arrangement. The mechanism of creation of such defects, in relation to the
elements can be added to the graphene pi-network, or Group III elements misalignment to the underlying crystallographic structure of the SiC
can provide extra holes, without adversely affecting carrier mobility. Using substrate is elucidated. The relation between the SiC surface structure,
MBE, we have substitutionally doped graphene with B and P. Ultraviolet including the presence of the single atomic steps, the sequences of atomic
photoelectron spectroscopy (UPS) is used to observe shifts in the Fermi steps, and also the macrosteps, and the emergence of edge dislocations or
level resulting from doping, and we have seen up to a 110 meV shift with boundaries between the regions having different crystallographic orientation
1% B in the lattice of graphene. Discussion of scanning tunneling in the graphene layers, is shown. In addition, the structures containing
microscopy (STM) observations of dopant placement and electrical different stacking sequences of carbon atoms in the graphene layers are
properties will be presented. Density functional theory has been used to presented. The presented C-layers stacking includes AA, AB, ABC
compute the density of states for the doped system in support of the STM sequences, and also the stacking close to turbostratic stacking.
and electrical measurements.
[1] S. S. Datta, D. R. Strachan, E. J. Mele, and A.T.C. Johnson, Nano Lett. 10:00am GR+SS+TF+EM-MoM6 Controlling the Growth Rate of
9 (2009) 7. Graphene on Silicon Carbide, D.B. Torrance, D.L. Miller, M. Phillips, H.
[2] Y. Dan, Y. Lu, N.J. Kybert, Z. Luo and A.T.C. Johnson, Nano Lett., 9 Tinkey, E. Green, P.N. First, Georgia Institute of Technology
(2009) 1472. Controlled thermal decomposition of silicon carbide is so far the most
effective method for growing high-quality graphene epitaxially and at the
[3] T. Filleter, K. V. Emtsev, Th. Seyller, and R. Bennewitz, Appl. Phys.
wafer scale. In this work we simultaneously study the graphenization of
Lett. 93 (2008) 133117.
SiC(0001) and SiC(000-1) as a function of temperature and buffer-gas
[4] G.G. Jernigan, et al., Nano Lett. 9, 2605 (2009). pressure in a custom-built ultrahigh vacuum (UHV) induction furnace. The
[5] J.L. Tedesco, B.L. VanMil, R.L. Myers-Ward, J.M. McCrate, S.A. Kitt, buffer gas is modeled as a homogeneous diffusion medium using kinetic
P.M. Campbell, G.G. Jernigan, J.C. Culbertson, C.R. Eddy, Jr., and D.K. theory. In-situ characterization by both Auger electron spectroscopy and
Gaskill, Appl. Phys. Lett., 95, 122102 (2009). low-energy electron diffraction (LEED) was used to determine the pressure-
and temperature-dependent growth rate of graphene layers. Sample quality
was further assessed ex-situ using a variety of techniques such as Raman
8:40am GR+SS+TF+EM-MoM2 The Role of Carbon Surface
spectroscopy and scanning tunneling microscopy.
Diffusion on the Growth of Epitaxial Graphene on SiC, T. Ohta, N.C.
Bartelt, S. Nie, K. Thürmer, G.L. Kellogg, Sandia National Laboratories
Growth of high quality graphene films on SiC is regarded as one of the 10:40am GR+SS+TF+EM-MoM8 Evidence of Screw Dislocations in
more viable pathways toward graphene-based electronics. Graphene films Epitaxial Graphene Islands, J.K. Hite, J.C. Culbertson, Naval Research
are readily formed on SiC by preferential sublimation of Si at elevated Laboratory, J.L. Tedesco, National Institute of Standards and Technology,
temperature. Little is known, however, about the atomistic processes of M.E. Twigg, A.L. Friedman, P.M. Campbell, R.L. Myers-Ward, C.R. Eddy,
interrelated Si sublimation and graphene growth. We have observed the Jr., D.K. Gaskill, Naval Research Laboratory
formation of graphene on SiC by Si sublimation using low energy electron Epitaxial graphene (EG) has lately garnered enormous interest, due to its
microscopy, scanning tunneling microcopy, and atomic force microscopy. high free-carrier mobility and compatibility with semiconductor processing.
This work reveals unanticipated growth mechanisms, which depend In fact, the first EG RF field effect transistor has been demonstrated.1
strongly on the initial surface morphology. Carbon diffusion governs the However, the growth mechanism of this material is not well understood.
spatial relationship between Si sublimation and graphene growth. Isolated Current RF device work has been on the Si polar face of (0001) semi-
bilayer SiC steps generate narrow ribbons of graphene by a distinctive insulating SiC substrates as EG on this face mainly consists of 1 monolayer
cooperative process, whereas triple bilayer SiC steps allow large graphene of graphene. In contrast, the C-face consists of a dozen or more graphene
sheets to grow by step flow. We demonstrate how graphene quality can be layers and has a rougher morphology. Yet, there is significant interest in
improved by controlling the initial surface morphology to avoid the obtaining few layer, smooth EG on the C-face of SiC due to its better
instabilities inherent in diffusion-limited growth. This work is supported by electrical properties as compared to the Si-face. Recently, it was shown that
the LDRD program at Sandia Labs and the US DOE Office of Basic Energy C-face EG grown in Ar ambient slows the growth rate, and under certain
Sciences, Division of Materials Science and Engineering (DE-AC04- conditions results in islanding of the graphene on the C-face.2 These islands
94AL85000), and was performed in part at CINT (DE-AC04-94AL85000). open the possibility of investigating the initial stages of graphene growth.
Sandia is a multiprogram laboratory operated by Sandia Corporation, a Electron channeling contrast imaging (ECCI) has previously been used to
Lockheed Martin Co., for the U.S. DOE NNSA (DE-AC04-94AL85000). investigate threading dislocations in semiconductors such as GaN and
SiC.3,4 In this work, ECCI is used for the first time to investigate graphene
island morphology as a function of island size and growth conditions. Using
5 Monday Morning, October 18, 2010
this characterization tool, single threading screw dislocations (TSDs) have
been found in the center of small EG islands (>20μm diameter). ECCI

images confirm that these small graphene islands are forming in hexagonal
recesses below the surface of the SiC substrate. For larger islands, the
evidence of TSDs disappears suggesting that as the islands grow or coalesce
Frontiers in Inkjet Technology Topical Conference
to larger diameters either the TSD becomes buried or no longer contributes
to growth. Once the islands become this large, the graphene begins to grow Room: Tesuque - Session IJ+BI+MN-MoM
above the SiC surface, unlike the smaller islands. After removal of the EG
by various methods, TSDs are still observed in the centers of the pits
Frontiers in Inkjet Technology
formed by the small island graphene growth. After some removal efforts,
many pits retained small triangles of graphene around the TSD . These Moderator: T. Boland, University of Texas at El Paso
results are consistent with Raman and AFM maps of the islands that
demonstrate that the centers of the islands are much deeper and the
8:20am IJ+BI+MN-MoM1 Drop Impact on Liquid, Solid and Porous
graphene thicker than the surrounding graphene. The evidence of TSDs in
Surfaces, A.L. Yarin, University of Illinois at Chicago INVITED
the centers of these C-face EG islands strongly suggests that these
dislocations serve as nucleation sites for EG growth, where the TSD may The talk covers drop impacts on thin liquid layers, dry impermeable
provide an escape pathway for sublimated silicon atoms during the growth surfaces, and porous surfaces with nano-scale texture. Splashing and corona
process. formation and propagation on liquid layers are discussed first. Then, some
additional kindred, albeit non-splashing, phenomena like drop spreading
1J.S. Moon et al., IEEE Electron Dev Lett 31, 260, 2010 and deposition, receding (recoil), jetting, fingering and rebound on liquid
2J.L. Tedesco et al., Appl Phys Lett, in press and dry impermeable solid surfaces are covered. A number of practical
3Y.N. Picard et al., Scripta Materiala 61, 773, 2009 applications of drop impacts are mentioned and relevant experimental,
theoretical and computational aspects are considered.
4Y.N. Picard et al., Appl Phys Lett 90, 23401, 2007
After that, a novel method of enhancement of drop and spray cooling for
microelectronic, optical and radiological elements and server rooms, which
11:00am GR+SS+TF+EM-MoM9 Direct Measurement of the Energy require extremely high heat fluxes, is discussed. The key idea of the method
Gaps Involved in the Lifting of the Valley and Spin Degeneracies in is to cover the heat transfer surfaces with electrospun nonwoven polymer
Epitaxial Graphene, Y.J. Song, A.F. Otte, CNST/NIST; Maryland nanofiber mats. The experiments reveal that drop impacts on nanotextured
NanoCenter UMD, D.B. Torrance, Y. Hu, P.N. First, W.A. de Heer, Georgia surfaces of nanofiber mats produce spreading similar to that on the
Institute of Technology, J.A. Stroscio, CNST/NIST
impermeable dry surfaces. However, at the end of the spreading stage the
Landau levels on epitaxially grown graphene were recently mapped both contact line is pinned and drop receding is prevented. All the mats appear to
spatially and energetically using scanning tunneling spectroscopy in be dynamically permeable for water drops. The enhanced efficiency of drop
magnetic fields at 4 K [1]. In this talk we present new measurements, made cooling in the presence of nanofiber mats observed experimentally results
at ≈10 mK, of all four electron states resulting from the lifting of the from a complete elimination of drop receding and bouncing characteristic of
fourfold spin- and valley-degeneracy of the N = 1 Landau level in applied the current spray cooling technology. Therefore, the drops evaporate
magnetic fields. We show that the energy splitting from the broken valley completely, and the large cooling potential associated with the latent heat of
degeneracy is ten times larger than electron spin splitting in our samples. water evaporation is more fully exploited. This is paradoxical: the best
When the Fermi level lies inside the four-fold Landau manifold, significant cooling can be provided by a "furry overcoat"! The results on drop impact
electron correlation effects result in an enhanced valley splitting at even on porous surfaces are also relevant for drop impacts on paper and
filling factors, and an enhanced electron spin splitting at odd filling factors. nonwovens in the context of ink-jet-printed microelectronics.
Most surprisingly, we observe new many body states with top-layer Landau
level filling factors 7/2, 9/2, and 11/2.
9:00am IJ+BI+MN-MoM3 Upper and Lower Bounds for the Stability
[1] David L. Miller, Kevin D. Kubista, Gregory M. Rutter, Ming Ruan, of Inkjet Printed Lines, B. Derby, J. Stringer, University of Manchester,
Walt A. de Heer, Phillip N. First, and Joseph A. Stroscio, Science 324, 924- UK
927 (2009). Many applications for inkjet printing require the ability to print continuous
linear features. Inkjet printing achieves this through the overlap and
11:20am GR+SS+TF+EM-MoM10 Morphology of Epitaxial Graphene coalescence of a series of liquid drops on a planar substrate, which then
on SiC: Nano-Objects, Nano-Cracks, and Ribbons, S. Chiang, Univ. of transform to a solid through phase change or solvent loss. In order to
California at Davis, N. Camara, IMB-CNM-CSIC, Spain, S. Vizzini, D. produce regular parallel sided printed lines, the intermediate fluid thread
Martinotti, CEA-Saclay, France, H. Oughaddou, Univ. de Cergy-Pontoise must retain morphhological stability prior to solidification. Drying fluid
& CEA Saclay, France, H. Enriquez, Univ. de Paris-Sud/Orsay & CEA- drops often show considerable hysteresis between the advancing and
Saclay, France, Ph. Godignon, IMB-CNM-CSIC, Spain, J. Camassel, GES, receding contact angles. This behaviour is shown to impose upper and
UMR-CNRS, France, P. Soukiassian, Univ. de Paris-Sud/Orsay & CEA- lower bounds for the width of a line formed by the overlap of printed drops.
Saclay, France The lower bound for line width is determined by the minimum separation
We use scanning tunneling microscopy/spectroscopy (STM/STS) and low distance for spreading drops to spread, overlap and coalesce. However, for
energy electron microscopy (LEEM) to investigate epitaxial graphene liquids with zero receding contact angles (as is the case for many
grown under vacuum on a 4H-SiC(000-1)-C-face substrate and self- evaporating solvents) there is a further limit for parallel sided lines [1]. The
organized parallel graphene ribbons grown in a furnace on a 6H-SiC(000-1) upper bound for line width is determined by a dynamic fluid instability that
C-face sample covered by a graphite cap. On the vacuum grown graphene, occurs through competing fluid flows between the spreading and
we observed two types of nanostructures including nano-objects and nano- coalescence processes [2]. This dynamic instability is a function of both
cracks. The results reveal that these nano-objects are located at the drop spacing and the rate of droplet deposition. By considering both the
graphene/SiC interface leading to electronic interface states. Their height upper and lower bound limits we can construct a map in a parameter space
profiles suggest that these objects are made of packed carbon nanotubes defined by drop size, drop spacing, drop/substrate contact angle and linear
confined vertically and forming mesas at the SiC surface. We also find printing velocity that shows the conditions under which stable linear
nano-cracks covered by the graphene layer that, surprisingly, is not broken features can be printed.
going deep into the crack, with no resulting electronic interface state.
Therefore, unlike the above nano-objects, these cracks should not affect the 9:20am IJ+BI+MN-MoM4 Particle Deposition and Assembly of
carrier mobility. LEEM has been used to observe the formation of graphene Inkjet-Printed Colloidal Drops in Line and Pattern Printing, A. Joshi,
ribbons grown on SiC in a furnace. The morphology and distribution of the V. Chhasatia, Y. Sun, Drexel University
ribbons has been examined, and their typical size is about 1 µm wide and 10 Precise control of process parameters during inkjet printing is essential to
µm long. enable uniform, accurate and repeatable deposition of functional materials.
In this work, we present a combined in-situ observation and computational
study to examine particle deposition and assembly during evaporation of
Work supported by Agence National pour la Recherche (ANR) under
inkjet-printed colloidal drops. Unlike previous computational models that
GraphSiC program
use tracer particles and known velocity fields inside the drop, our
computational model uses a multi-phase lattice Boltzmann method (LBM)
that directly simulates the flow of the liquid drop, surrounding vapor phase
and the motion of the liquid-vapor interface. The motion of suspended

particles within the liquid phase is directly coupled to the fluid flow and
also influences the velocity field in the liquid. Evaporation is accomplished
Monday Morning, October 18, 2010 6
by reducing the vapor pressure above the drop and different evaporation presence. The viability and function of the printed cells were evaluated by
modes including evaporation with contact line pinning and self-similar the live/dead and plasmid gene transfection experiments resulting in 98%
evaporation with a constant contact angle are examined. A novel viability and maintaining DNA function. Moreover, it has been recorded as
visualization technique is developed wherein aqueous suspensions of high throughput process printing 250,000 droplets/second. Due to the
fluorescent particles are jetted onto transparent surfaces and the evaporation reduction of volume, this method will increase the effectiveness of the
dynamics are observed in real-time using a fluorescence microscope. The resources utilized for emerging drug screening processes. The results show
effects of drop spacing, jetting frequency, substrate wettability, particle size promising usage of resources for future drug screening through new
and volume fraction, and environmental conditions (temperature and biochemicals.
humidity) on the final deposition morphology are presented for line and
pattern printing of functional materials on substrates.
11:00am IJ+BI+MN-MoM9 Inkjet Printing of Oxygen Releasing
9:40am IJ+BI+MN-MoM5 Inkjet Printing of Flexible Hybrid Solar Materials for Improved Cell Survival and Growth, A. Arteaga, T. Xu,
Cells based on P3HT and ZnO, G. Carryon, J.B. Baxter, Y. Sun, Drexel University of Texas at el Paso
University
Introduction: A major barrier in tissue engineering is the impossibility of
Inkjet printing of organic solar cells offers an inexpensive alternative to providing adequate oxygen to all cells within the engineered tissue before a
conventional solar cell fabrication methods. Despite the attractiveness of full vascularization is achieved. To overcome this limitation, a variety of
organic solar cells, they have demonstrated some degradation problems and oxygen-producing particles have been developed for improving tissue
have yet to achieve the efficiencies necessary to make them economically survival. However, most of these particles are used in random mixtures with
viable. In contrast to their organic counterparts, inorganic semiconductors scaffolding materials, which usually leads to an uneven distribution of
have demonstrated advantages in their high dielectric constant which oxygen in bioengineered tissues. An ideal oxygen supply requires a precise
facilitates carrier generation processes, high carrier mobility, and thermal spatial-temporal control of the oxygen-producing particles in scaffolds.
morphological stability. In recent years, improvements in device Unfortunately, current oxygen delivering scaffold techniques are unable to
performance have been seen in the development of organic-inorganic hybrid perform as described and to precisely incorporate oxygen particles into the
materials (e.g., ZnO nanoparticle-polymer composites or CdSe quantum scaffolds. Cell inkjet printing is a novel tissue fabrication approach, in
dot-polymer composites) as the photoactive layer. To date, most studies on which a special inkjet printer can be programmed to deposit cells and/or
hybrid solar cell fabrication have focused on using lab-scale spin-coating biomaterials of various types and sizes in a very precise pattern. In this
methods to deposit ZnO nanoparticle-polymer materials. In this paper, we study we have applied the inkjet printing technology to allocate oxygen
present our results in using an industrial piezoelectric-driven printing device releasing materials to their designed positions for optimal cell viability and
for inkjet printing of ZnO nanoparticles/nanorods-polymer [e.g., poly(3- growth.
hexylthiophene (P3HT)] ink materials for large-scale processing of hybrid

solar cells. The deposition morphology and properties of printed
photoactive layer are examined as a function of the solvent properties (e.g., Methods: The controlled oxygen-releasing platform is fabricated by
wettability and vapor pressure), particle size, volume fraction, and printing different patterns (“Black”, “White”, “Grey”, and “Dots” to
polydispersity, as well as the aspect ratio of nanorod. The effects of jetting represent different densities of the oxygen particles on the substrates) of
parameters (e.g., wave form and jetting frequency) and printing patterns on encapsulated calcium peroxide (CPO) particles that were analyzed against
film thickness and uniformity are also discussed in detail. Finally, the C2C12 mouse myoblast cell line for cell viability. CPO has been found to
feasibility of printing P3HT onto aligned ZnO nanorod arrays for novel release its oxygen over an extended timeframe. The effects of controlled
heterogonous nanostructures for reduced exciton diffusion lengths is oxygen-releasing particles on cell viability were analyzed using the cell
explored. morphology study, live/dead assay, and the MTS assay.

10:00am IJ+BI+MN-MoM6 Anomalies in Applications of Inkjet Results: These analyses showed the concentration of the oxygen-releasing
Printing in Microfluidic Device Fabrication, W.E. Dieterle, C.P. particles in “Black” was toxic to the cells based on the decreasing trend in
McNary, California University of Pennsylvania
cell viability. The “White” did not have oxygen-releasing particles, which
Utilization of inkjet-generated masks for UV photosensitive materials as a correlates to the decrease in cell viability over time due to oxygen
cost-effective method for the generation of microfluidic devices requires deprivation. Both “Grey” and “Dots” showed a similar trend in absorbency,
resolution of certain anomalies related to combinations of various color in which the absorbency was low at 24 hours, there was an increase in
components. These anomalies are demonstrated for UV exposures with a absorbency at 48 hours, and then an abrupt decrease at 72 hours. Both these
high-pressure mercury vapor source and possible solutions are discussed, results suggest that the amount of oxygen released was beneficial to the
including implications for inkjet manufacture designs targeted to similar cells within the first 48 hours, yet may not have been sufficient to sustain
applications. cell viability after that time span. The cells treated in the printed “Dots”
showed to have the most compatible treatment for an overall increase in cell
10:40am IJ+BI+MN-MoM8 Fabrication of Miniature Drug Screening viability.
Platform Utilizing Low Cost Bioprinting Technology, J. Rodriguez, T.
Xu, University of Texas at el Paso

In the pharmaceutical industry, new chemicals and substances are being
tested to find appropriate compounds for treating a specific disease. The Conclusion: The amount of oxygen released can be controlled to optimize
demand for screening large compound collections against and increasing the cell by bioprinting different densities of the oxygen releasing materials
number of therapeutic targets has stimulated technology development in the onto a substrate.
areas of assay automation and miniaturization. Current methods for
evaluating the reactions of cells use a relatively large volume in the range
from microliters to milliliters; since reliability has to be met, it exists the
11:20am IJ+BI+MN-MoM10 Understanding Volume Ejection of
need to have several assays to confirm the biochemical reactions, which
Complex Fluids through Pressure Measurements, G.E. Mårtensson, W.
ultimately cause the usage of large amounts of volume for each substance.
Holm, Micronic Mydata AB, Sweden
Unfortunately, some of these new compounds are rather hard to obtain,
In conventional ink jetting applications, a pressure difference is used to
which causes an expensive researched and limited material availability;
ensure the continuous and prompt filling of the jetting chamber between
therefore, increasing the time development for future cures. We have
jetting actuations. The delivery of precise fluid volumes utilizing inkjet-like
developed a new and low-cost deposition method to fabricate miniature
drop-on-demand jetting technology is primarily controlled by the piezo
drug screening platform that can realistically and inexpensively evaluate
voltage that actuates the jetting chamber (Gerhauser et al. 1983, SID 83
biochemical reactions up to 4 substances per trial in a picoliter-scale
Digest). The jetting of large volumes, in excess of 1 nL, of complex viscous
volume.
fluids is complicated by the difficulty of filling the ejection chamber
quickly after the previous droplet ejection.
This study focues on the development of the controls for a deposition A novel jetting mechanism for highly viscous complex fluids, that utilizes a
method (inkjet printing technology) which will simultaneously place viscous micropump to control the amount of fluid that is ejected by a piezo
therapeutic drugs and cells onto target sites to fabricate cell/drug chips for actuated mechanism, has been developed and implemented by the authors.
drug screening application. Using a modified HP 5360 CD printer, droplets In this paper , we report results of volume, exit velocity, and pressure
of GFP expressing Escherichia coli have been deposited in an agar coated measurements. The piezo voltage, V, and the angular speed, N, of the
p
coverslip chip as small reliable volume of 180 picoliters per each colony viscous pump has been varied. A chosen V translates directly to displaced
p
dot, along with this bacteria it has been patterned different antibiotics in volume and N to flow rate.
such a way that we evaluated the growth of the bacteria under antibiotics
7 Monday Morning, October 18, 2010
The ejected volume has been measured by weighing a large number of based on fixed dipoles. Using apolar contact angle liquids of either purely
droplets and via 3D profilometry methods. It has been shown in the London dispersion or London dispersion and dipole/induced dipole
experimental jetting setup that the volume of a jetted deposit is only interactions we calculated the apolar component of the surface tensions of
affected to a minor degree, of the order of 5% of the target volume, by the SAMs and bacteria and observed differences in the estimation of the apolar
chosen piezo voltage, V. Thus the ejected volume is almost independent of surface tension and, thus, the total surface tension on polar surfaces. The
p
the displaced volume within the experimental range and determined by the second assumption is that the Lewis acid and base components of H
2O
flow rate, which in turn is controlled by N. surface tension are equal, which frequently leads to overestimation of Lewis
basicity. We calculated surface tensions of bacteria and SAM surfaces with
The exit velocity of the jet has been measured using high speed double
both LAB values and those based on solvatometric hydrogen bonding
exposure imaging. It has been shown that the speed of the ejected droplet
calculations and observed that the latter gave more reasonable estimation of
has a nearly linear response to V (at least for all but the smallest N). For a
p the free energy of attachment. The third assumption is that interactions can
given V, the exit velocity increase with increasing N. Thus, it seems that a
p be correlated with average surface energy for the cell. Both our observations
larger displaced volume results in a higher exit velocity, but the ejected
and those in the literature have led us to believe this is untrue. We present
amount is unaffected.
scanning electron microscopy data that demonstrate that different parts of
In order to probe these seemingly counterintuitive results, the pressure in bacterial cells are in contact with the surface of different SAMs and that
the ejection chamber, as well as in the viscous micropump, was measured SAMs on nanoparticles can identify specific regions of heterogeneity on
over a large number of ejection cycles. The volume of the resulting bacterial cell surfaces. Based on our results we propose modifications to the
depositions were correlated with the chamber and pump pressures. LAB model that may make it more able to model and predict marine
Additional measurements were performed to correlate the speed of the bacterial attachment.
resulting shot with the chamber and pump pressures. Simple models are
proposed to correlate the above mentioned quantities.
9:00am MB+BI-MoM3 Reversible Adhesion in Barnacle Cyprids: the
Weak Link in Surface Colonisation?, N. Aldred, Newcastle Univ., UK,
11:40am IJ+BI+MN-MoM11 Determination of Effective Jet Radius I.Y. Phang, MESA+ Institute for Nanotech. and Dutch Polymer Inst.,
from Measurements of the Perturbation Growth Rate in Thermally Netherlands, T. Ekblad, O. Andersson, B. Liedberg, Linköping Univ.,
Stimulated Continuous Microjets, J.M. Grace, G. Farruggia, E.P. Sweden, G.J. Vancso, MESA+ Institute for Nanotech. and Dutch Polymer
Furlani, Z.J. Gao, K.C. Ng, Eastman Kodak Company Inst., Netherlands, A.S. Clare, Newcastle Univ., UK INVITED
Drop formation in continuous inkjet devices is based upon the Rayleigh- Reversible or temporary adhesion allows barnacle cyprids to explore
Plateau instability – a phenomenon in which surface tension drives the surfaces before they commit to permanent settlement. As such this scarcely
break-up of a column of fluid into droplets. In thermally stimulated studied system is an obvious point of attack for fouling control. The
continuous inkjet devices, heat pulses applied to the jet at the nozzle couple remarkable paired antennules of the cyprid bear attachment discs; hairy
to the instability to stimulate drop formation. The level of stimulation adhesive structures that enable the cyprid to walk over surfaces in a stilt-
depends upon the size of the effective perturbation and its growth rate along like fashion while resisting detachment by hydrodynamic forces. A
the jet. While the growth rate depends upon characteristics of the jet itself proteinaceous secretion at the surface of the disc has been postulated to
(fluid properties and jet diameter), the effective perturbation depends upon function as a ‘temporary adhesive’. Here evidence is presented that suggests
coupling between the source of stimulation and the jet, as well as the fluid the antennular secretion is related to the adult settlement pheromone – the
properties. The coupling efficiency can be inferred from measurements of settlement-inducing protein complex – and that it functions as a reversible
the perturbation growth rate and the jet diameter. For liquid microjets with adhesive, but in a hybrid wet/dry adhesive system somewhat akin to insect
diameters of 10 micrometers or less, direct determination of the jet diameter reversible adhesion. While a complete characterisation of the antennular
by optical microscopy is extremely challenging. Although the lateral secretion remains an aim, the application of surface analytical techniques
dimensions of the microjets may be difficult to measure precisely, the (atomic force microscopy and imaging surface plasmon resonance) and
break-up length can be determined with relatively good precision. direct measures of cyprid behaviour, go some way to providing a
Measurements of break-up length as a function of input power provide a mechanistic understanding of why cyprids settle at low rates on certain
means to determine the perturbation growth rate. From the experimentally surfaces, which can be applied to future developments in antifouling
determined growth rate as a function of stimulation frequency, the diameter technology.
of the microjet can be determined by fitting to a model for jet break-up. The
experimentally determined growth rate and jet diameter provide a basis for
9:40am MB+BI-MoM5 Chemical Insights on How Shellfish Stick, J.D.
comparing the effective coupling for different designs of jetting modules.
White, C.R. Matos-Perez, J.R. Burkett, T.W. McCarthy, J.W. Wilker,
Measurements of jet break-up and methods for determining the effective jet
Purdue University INVITED
diameter will be presented and discussed.
Since the very first mariners traversed ocean waters, hulls have become
encrusted with fouling organisms such as barnacles, oysters, tube worms,
and algae. Antifouling coatings can prevent the resulting loss of vessel
Marine Biofouling Topical Conference
performance, but at a cost. Current coatings release toxins into the water,
Room: Navajo - Session MB+BI-MoM thereby killing the foulers as well as other species. Rather that destroying
marine life, stopping bioadhesion processes may provide a benign means of
antifouling. Consequently we have been seeking detailed knowledge of how
Understanding Marine Biofouling
shellfish attach themselves to surfaces. The resulting insights can be used to
Moderator: S. Zauscher, Duke University develop mechanism-based antifouling coatings for inhibiting the production
of bioadhesives. Our characterization efforts have focused on the intractable
glues and cements of mussels, barnacles, and oysters. A fruitful approach
8:40am MB+BI-MoM2 Colloidal Theories of Bacterial Attachment as
has been to work simultaneously with synthetic peptide models, extracted
Applied to Marine Bacteria: A Necessary Revision?, L.K. Ista,
adhesive proteins, and material produced by the animals. Perspectives from
University of New Mexico, G.P. Lopez, Duke University
each class of experiments can be complimentary and used to build pictures
The majority of our knowledge of bacterial attachment and subsequent
of how the animals generate their adhesives. Themes in marine bioadhesion
biofilm formation has been gleaned from studies on human pathogens and
are beginning to emerge as well as evidence for unique aspects within each
commensal bacteria with specialized attachment mechanisms and
system. Cross-linking of proteins plays a prominent role in curing the glues.
attachment substrata. In contrast many marine microorganisms have a
Inorganic reactions and related oxidative chemistry also contribute to
variety of substratum choices, with the added challenge of new types of
formation of the materials. Here we will present a summary of our latest
introduced substrata (boats, piers, pilings) as possible biofilm supports.
findings on how shellfish stick.
Maintaining the genetic information needed to produce specific attachment
mechanisms for each possible substratum would be maladaptive; it is very
likely that marine bacteria exploit their colloid-like size and rely on 10:40am MB+BI-MoM8 Investigation of Early Marine Biofouling
colloidal interactions to drive attachment. Thus, colloidal models of Events on Model Organic and Polymeric Surfaces, G.P. Lopez, Duke
bacterial attachment are of particular interest to understanding marine University INVITED
microbial attachment. Current models of bacterial attachment are useful for Marine biofouling -the accumulation of unwanted biomass on solid
describing some bacterial attachment, but cannot predict attachment structures- is of major concern to maritime pursuits. Biofouling can not only
behavior in most cases. In this work we examine 3 basic assumptions of the decrease performance of deployed marine equipment, such as ships or oil
preeminent model used for bacterial attachment, the Lewis Acid Base rigs, but can also result in the transport of invasive species between ports of
(LAB) model proposed by van Oss. We used gold-alkanethilate self- call. The problem of biofouling is at first a problem of microbial interaction
assembled monolayers (SAMs) and three marine bacteria to test these with the water-solid interface; bacteria and diatoms themselves can form
assumptions. The first assumption is that apolar interactions include both detrimental biofilms and can further enable the settlement of macrofoulers.
London dispersion (induced dipole/induced dipole) interactions and those This talk will present studies that seek to shed light on underlying chemical
Monday Morning, October 18, 2010 8
factors that lead to the initial attachment of metabolically homogenous offers an excellent route to achieve large-scale implementation of
populations of model marine bacterial populations to well-defined organic electrochromic films. Important ultrasonic spray variables include substrate
and polymeric surfaces. It will also present studies of the use of stimuli- temperature, precursor concentration, carrier solvent and other parameters
responsive surfaces to allow release of attached marine biofilms. related to solution atomization. The electrochromic properties of these films
were characterized by performing cyclic voltammetry in registry with in
situ measurements of optical transmission. Particular attention is paid to
11:20am MB+BI-MoM10 The Promise of Fouling Deterrence as a
optimizing performance metrics such as coloration efficiency and cycling
Natural Marine Antifouling Strategy, A.S. Mount, Clemson University
INVITED stability. Using the measurements described above, we will evaluate the
important process-structure-performance relationships in these systems.
Marine biofouling is the unwanted accumulation of bacteria, algae, plants
and marine animals on submerged structures including ships. Unfortunately,
man’s attempts to develop effective antifouling coatings have had 9:20am NS-MoM4 Monitoring Charge Storage Processes in Nanoscale
deleterious effects on marine life and a less toxic deterrent to cuprous oxide Oxides using Electrochemical Scanning Probe Microscopy, K.R.
based paints are needed. Larval marine invertebrates have highly developed Zavadil, J. Huang, P. Lu, Sandia National Laboratories
sensory organs which investigate surfaces prior to settlement, attachment Advances in electrochemical energy storage science require the
and metamorphosis. We investigated this tactile chemical sense as a development of new or the refinement of existing in situ probes that can be
potential natural antifouling strategy by covalently linking the used to establish structure – activity relationships for technologically
neuroendocrine hormone noradrenaline (NA) to relevant materials. The drive to develop reversible, high capacity electrodes
poly(hydroxyethylmethacrylate) and to poly(methacrylic acid) polymer from nanoscale building blocks creates an additional requirement for high
surfaces. NA was selected since it is well established that the soluble form it spatial resolution probes to yield information of local structural,
inhibits larval settlement in mollusks, barnacles, bryozoans and annelid tube compositional, and electronic property changes as a function of the storage
worms, all of which are major macrofoulers. The NA conjugate polymer state of a material. In this paper, we describe a method for deconstructing a
surfaces induced oyster cellular apoptosis when compared to negative lithium ion battery positive electrode into its basic constituents of ion
controls and also deter the settlement of barnacle and oyster larvae. Fouling insertion host particles and a carbon current collector. This model system is
deterrence is promising strategy in that only treated surfaces would deter then probed in an electrochemical environment using a combination of
biofouling thus eliminating the need to release of any toxic substances into atomic force microscopy and tunneling spectroscopy to correlate local
the oceans. activity with morphological and electronic configurational changes. Cubic
spinel Li Mn O nanoparticles are grown on graphite surfaces using
1+x 2-x 4
vacuum deposition methods. The structure and composition of these
Nanometer-scale Science and Technology particles are determined using transmission electron microscopy and Auger
microprobe analysis. The response of these particles to initial de-lithiation,
Room: La Cienega - Session NS-MoM
along with subsequent electrochemical cycling, is tracked using scanning
probe microscopy techniques in polar aprotic electrolytes (lithium
Oxide Based Nanoelectronics hexafluorophosphate in ethylene carbonate:diethylcarbonate). The
relationship between nanoparticle size and reversible ion insertion activity
Moderator: C. Nakakura, Sandia National Laboratories
will be a specific focus of this paper.
This work is funded within the Nanostructures for Electrical Energy
8:40am NS-MoM2 Oxidation Kinetics of Electron Beam Evaporated Storage, an Energy Frontier Research Center funded by the U.S.
Nano Copper Thin Films by Kelvin Probe Measurements, A. Department of Energy, Office of Science, Office of Basic Energy Sciences
Subrahmanyam, IIT Madras, India under Award Number DESC0001160. Sandia is a multiprogram laboratory
Copper is a very good interconnect in microelectronics because it has a high operated by Sandia Corporation, a Lockheed Martin Company, for US
thermal and electrical conductivities and low electromigration resistance. DOE’s NNSA under contract DE-AC04-94AL85000.
However, the formation of an oxide layer on Cu (even at room temperature)
induces trap states at the Cu/Cu oxide interface that can ultimately cause a 9:40am NS-MoM5 Tuning Superconductivity at the LaAlO/SrTiO
decrease in its thermal and electrical conductivities, as well as a significant 3 3
Interface, A.D. Caviglia, S. Gariglio, N. Reyren, C. Cancellieri, A. Fête,
degradation in its interconnection capabilities. These effects become more
University of Geneva, Switzerland, M. Gabay, University of Paris-Sud,
and more critical when the copper is in nano form for use in ULSI. The France, J.-M. Triscone, University of Geneva, Switzerland INVITED
partial oxides of copper can also be a very good candidate for plasmonic
Electronic states with unusual properties can be promoted at interfaces
structures.
between complex oxides [1]. A striking example is the interface between
Copper exhibits two valences. The size effects and partial oxidation of the band insulators LaAlO and SrTiO, which displays conductivity with
3 3
copper bring significant changes in the electrical resistivity. Thus the high mobility and 2D superconductivity [2,3]. We will discuss recent
surface oxidation kinetics of nano copper are important. In the present experiments that revealed the sensitivity of the normal and superconducting
communication, pure copper thin films have been prepared by electron state to external electric fields. Using the electrostatic field effect, the phase
beam evaporation technique on cleaned glass substrates at 500 K. The diagram of the system has been mapped out, revealing a quantum phase
thickness is varied in the range : 20 nm to 300 nm. The electrical resistivity transition between a superconducting state and an insulating state [4]. We
of these films ranges from 5.201*10-6 Ω cm to 9.206*10-6 Ω cm. The carrier will also lay out an example of an electronic property arising from the
concentration and electron mobility have been evaluated by Hall interfacial breaking of inversion symmetry, namely a large spin-orbit
measurements. In order to follow the surface oxidation kinetics of copper interaction, whose magnitude can be modulated by the application of an
thin films with varying grain sizes exposed to the ambient at 300K, the external electric field [5].
contact potential (cpd) / work function measurements by Kelvin probe
[1] E. Dagotto, Science 318, 1076 (2007)
technique have been performed. The increase in the contact potential
difference (cpd) indicates the oxidation kinetics of these films. [2] A. Ohtomo, H. Y. Hwang Nature 427, 423 (2004)
[3] N. Reyren, S. Thiel, A. D. Caviglia, L. F. Kourkoutis, G. Hammerl, C.
9:00am NS-MoM3 Hot-wire Chemical Vapor Deposition of Tungsten Richter, C. W. Schneider, T. Kopp, A.-S. Ruetschi, D. Jaccard, M Gabay,
Oxide Nanoparticles for Use in Energy Applications, C.-P. Li, C.A. D. A. Muller, J.-M Triscone, J Mannhart Science 317, 1196 (2007).
Wolden, Colorado School of Mines, R. Tenent, A.C. Dillon, National [4] A. D. Caviglia, S. Gariglio, N. Reyren, D. Jaccard, T. Schneider, M
Renewable Energy Laboratory Gabay, S. Thiel, G. Hammerl, J. Mannhart, J.-M Triscone Nature 456, 624
Crystalline tungsten oxide nanoparticles were synthesized by hot-wire (2008).
chemical vapor deposition (HWCVD). These materials are being examined
[5] A. D. Caviglia, M Gabay, S. Gariglio, N. Reyren, C. Cancellieri, J.-M
for use in numerous energy related applications including electrochromic
Triscone Phys. Rev. Lett. 104, 126803 (2010).
windows and fuel cells. It is possible to tune the particle morphology by
changing key synthesis parameters including filament temperature,
substrate temperature, and oxygen partial pressure. The resulting
nanostructures are characterized by a number of techniques including
transmission electron microscopy, X-ray diffraction, and Raman
spectroscopy. The dependence of nanoparticle size and morphology will be
described both as a function of HWCVD synthesis conditions as well as
post-deposition annealing treatments. The resulting nanoparticles are
suspended in solution and used to form thin films on transparent conducting
oxide coated glass substrates using an ultrasonic spray deposition process.
Ultrasonic spray coating is a cost effective, scalable deposition process that
9 Monday Morning, October 18, 2010
10:40am NS-MoM8 Fabrication and Characterization of Ferroelectric nanoscale spatial resolution of Raman scattering spectroscopy can provide
BiFeO Nanocapacitors for Next Generation FeRAMS, L.E. Ocola, S. insightful information on the possible routes of impurity incorporation,
3
Hong, R. Nath Premnath, W. Li, Argonne National Laboratory, S. Jackson, shedding light on the relationship between nanowire synthesis conditions
Illinois Mathematics and Science Academy, R. Katiyar, University of and material properties.
Puerto Rico, O.H. Auciello, Argonne National Laboratory

In this work, using Raman scattering spectroscopy complemented by mass-
11:00am NS-MoM9 Polarization-Dependent Electron Transport in selected time-of-flight particle emission techniques, we show the presence
Thin Films of Uni- and Multiaxial Ferroelectrics, P. Maksymovych, Oak of unintentionally incorporated nitrogen complexes (most likely interstitial
Ridge National Laboratory, J. Seidel, University of California, Berkeley, S. nitrogen molecules) in ZnO and GaN nanowires grown via the vapor-liquid-
Jesse, Oak Ridge National Laboratory, P. Yu, Y.-H. Chu, University of solid (VLS) process. Spatially resolved Raman scattering spectra obtained
California, Berkeley, A.P. Baddorf, Oak Ridge National Laboratory, R. at various locations on single nanowires suggest a possible route of nitrogen
Ramesh, University of California, Berkeley, S.V. Kalinin, Oak Ridge incorporations via metal nanocatalysts during the growth. As nitrogen
National Laboratory
impurities have profound effects on electronic properties of ZnO and GaN,
The intrinsic coupling of soft-phonon order parameters and electron these results have significant implications for current efforts on realizing
transport in ferroic materials can usher a wide range of novel physical high-performance opto-electronic device applications based on these
phenomena with potential for new applications in information technology, nanomaterials. In addition, with the VLS process as one of the most
energy harvesting and quantum computing. In this talk we will present local common growth modes for synthesizing semiconductor nanowires, these
conductivity and piezoresposne measurements on the surfaces of uniaxial experimental findings might be relevant for many nanowire systems,
(Pb(Zr0.2Ti0.8)O3) and multiaxial (BiFeO3) perovskite ferroelectrics, with signifying the necessity of more studies on unintentional impurity
film thicknesses ranging from 30 nm to 100 nm. Conductive atomic force incorporation in these nanomaterials.
microscopy revealed that most of these films possesses highly non-linear,
and often hysteretic current-voltage characteristics, and in many cases the
hystereses could be correlated to local polarization switching induced by the
Plasma Science and Technology
electric field of the AFM tip. In lead zirconate titanate, the large
spontaneous polarization produced up to 500-fold enhancement of local Room: Aztec - Session PS-MoM
conductivity, and the film remained sufficiently conducting in the bias-
region significantly smaller than the switching voltage. As a result, this
Advanced BEOL / Interconnect Etching I
effect can be used for a non-destructive and resistive read-out of the
polarization state on length-scales down to 10 nm, implementing a Moderator: K. Kumar, TEL Technology Center America
prototypical memory function. Extending the I-V measurements to low-
temperatures revealed a strong exponential dependence of the conductivity.
8:20am PS-MoM1 Plasma Processes Challenges for Porous SiOCH
We developed a novel analysis scheme, which enabled identifying trap-
Patterning in Advanced Interconnects, N. Posseme, CEA-LETI-
assisted Fowler-Nordheim tunneling and Poole-Frenkel hopping as two
MINATEC, France, T. Chevolleau, CNRS-LTM, France, T. David, CEA-
dominant mechanisms behind non-linear I-V curves. Curiously, we have
LETI-MINATEC, France, M. Darnon, CNRS-LTM, France, F. Bailly, R.
been able to separate the contributions due to interface- and bulk-limited
Bouyssou, J. Ducote, C. Verove, STMicroelectronics, France, O. Joubert,
conduction, as well as to visualize spatially-resolved variations due to each
CNRS-LTM, France INVITED
transport regime.
The choice of copper/Low-k interconnects architecture is one of the keys
We will further discuss the peculiarities of local electron transport through for integrated circuits performances, process manufacturability and
BiFeO3, and in particular the mechanism behind local conductivity of 109o scalability. Today, the implementation of porous low-k material becomes
ferroelastic domain walls. Based on a statistical analysis of I-V curves and mandatory in order to minimize the signal propagation delay in the
simultaneous measurements of local transport and piezoresponse, we interconnections. In this context, the traditional plasma processes issues (the
suggest that the domain wall is not a static conducting object under a biased plasma-induced damages, dimension and profile control, selectivity) and
tip, but instead that a transient, local and microscopically reversible new emerging challenges (sidewalls surface roughness, dielectric wiggling)
topological distortion of polarization structure at the wall contributes to become the critical points to control the reliability and defectivity.
enhanced electron transport. In particular, it produces a seminal example of
Based on plasma-surface interaction understanding, the main issues and
ferroic memristive functionality.
also the potential solutions will be illustrated through different process
The measurements were conducted at the Center for Nanophase Materials architecture using metallic or organic hard masks strategies.
Sciences sponsored at Oak Ridge National Laboratory by the Division of
Scientific User Facilities, U.S. DOE.
9:00am PS-MoM3 TiN Selectivity Improvement by DC Voltage Effect
[1] P. Maksymovych, S. Jesse, P. Yu, R. Ramesh, A. P. Baddorf, S. V. in a DC+ Dual Frequency Capacitive Coupled Plasma Etcher, M.
Kalinin, Nishino, M. Honda, Y. Ooya, R. Shimizu, Tokyo Electron AT Limited,
Science 324 (2009) 1421. Japan
Metal Hard Mask(TiN) damascene scheme has been chosen by many logic
[2] P. Maksymovych, J. Seidel et. al, submitted (2010)
semiconductor manufacturers for 2x or beyond BEOL processes. Due to
issues related to Aspect Ratio, wiggling, and integration with low
11:20am NS-MoM10 Observation of Unintentionally Incorporated mechanical stress resistant porous low-k dielectric materials, TiN hard mask
Nitrogen Complexes in Vapor-Liquid-Solid Grown ZnO and GaN has become thinner and less resistant to etch. As the technology node
Nanowires, A. Soudi, Y. Gu, Washington State University
decreases to sub 20nm, Self-Aligned Via(SAV) process will be introduced
Semiconductor nanowires have been intensively explored as building for MHM dual damascene scheme to maintain Via CD within the confined
blocks for the next-generation electronic and opto-electronic devices. specifications of the MHM. With this scheme, TiN MHM is exposed to RIE
Further advances towards real-world applications require a reliable and etch twice: once during partial via formation and another in trench etch.
precise control of material properties, which, to a large extent, are Due to such tight process margins, many semiconductor manufacturing
determined by impurities. Controlled incorporation of functional impurities companies are focusing on high selective chemistry for TiN during both Via
enables an impurity-engineering approach, whereby novel material and Trench dielectric etch process. The DC+ Dual frequency etcher is a
properties can be engineered based on the interactions between impurities capacitive coupled plasma etcher with a superimposed DC voltage. This
and the one-dimensional material host. On the other hand, unintentional configuration has been proven to be more effective for maintaining TiN
impurity incorporation can be significant in determining nanowire hard mask during dielectric etching. A negative DC bias is applied to the
electronic properties. Therefore, efforts towards identifying impurity upper Si electrode. The Si electrode surface reacts with CFx radicals from
species, especially those incorporated unintentionally, as well as fluorocarbon based plasma and the fluorine component of bulk plasma was
understanding their microscopic structures and effects on material reduced. This phenomenon is the interaction between fluorocarbon based
properties, are critical to advancing nanowire-based device technologies. plasma and Si electrode which was induced by DC voltage. This paper
presents an investigation of TiN hard mask high selective process from this
interaction. We measured Ne and Vdc areas of MHM trench process both
To this end, Raman scattering spectroscopy provides an effective approach
with and without DC voltage conditions and investigated the direction of
to probing impurity incorporation in various materials. When
Ne/Vdc windows as MHM trench process at first . We evaluated this
complemented by mass spectrometry studies, this technique can enable
interaction effect from Ne and Vdc trend with DC voltage and observed that
unambiguous identifications of impurity species by their vibrational
DC voltage did not only acquire higher TiN selectivity to dielectric
frequencies (i.e. impurity vibrational modes). As impurity vibrational
(maintain TiN thickness) but also reduce TiN HM facet etching rate (control
characteristics are sensitive to the surrounding environment, the lattice
locations of these impurity atoms can also be determined. Furthermore, the
Monday Morning, October 18, 2010 10