Development of HgCdTe large format MBE arrays and and noise free high speed MOVPE arrays ...

50 Pages·2014·4.17 MB·English

Development of HgCdTe large format MBE arrays and
and noise free high speed MOVPE arrays
for ground based NIR astronomy

G. Finger1, I. Baker2, M. Downing1, D. Alvarez1, D. Ives1, L. Mehrgan1, M. Meyer1, J. Stegmeier1, H. J. Weller2
1European Southern Observatory, GarchingGermany.
2 Selex ES Ltd, Southampton, United Kingdom.
VLT / VLTI Interferometer
the spatial

resolution of the
four 8m telescopes
of the VLTI will
outperform the
ELT
200 m baseline

(ELT 40m)
fringe tracker

IR AO WFS

for each telescope
high speed low

noise sensor
required
European
Extremely Large Telescope

Large format detectors
required (4Kx4K)
Armazones
Paranal
The E-ELT
• 40-m class telescope: largest optical-
infrared telescope in the world.
• Segmented primary mirror.
• Active optics to maintain collimation
and mirror figure.
• Adaptive optics assisted telescope.
• Diffraction limited performance.
• Wide field of view: 10 arcmin.
• Mid-latitude site (Armazones in Chile).
• Fast instrument changes.
• VLT level of efficiency in operations.
FPA arrangement for MICADO
Science Detectors
Instrument Number of Det Pixel format Wavelength um
MICADO 13-16* 4kx4k 0.8-2.5
HARMONI 8* 4kx4k 0.95-2.45
8 4kx4k 0.47-0.95
METIS 1 1kx1k 5-14(28)
6 2kx2k 3-5
ELT-MOS 6* 4kx4k 0.6-1.7
6-8 4kx4k or 6kx6k 0.37-1
ELT-HIRES 3* 4kx4k 0.8-2.45
5 9kx9k 0.3-0.8
ELT-PCS 4* 4kx4k 0.95-1.65
8 4kx2k 0.6-0.9
Large format LPE / MBE
• LPE: homojunctions , not possible to vary bandgap
panchromatic response, QE lower in J band, cosmetic worse,
requires cooling to <60K, historical

• MBE: heterojunctions , solid state engineering possible,
vary bandgap for each molecular layer,
solid state engineering
• High QE > 80%
• Low dark current: few electrons/hour
• Low readout noise: DCS < 8 erms
Fowler < 3 erms
• Readout noise limited by IR diode, not by acquisition chain
• Remaining problem: persistence
Hawk-I mosaic : 2x2 2Kx2K Hwaii-2RG mosaic
Hawk-I mosaic : 2x2 Hwaii-2RG