Publication Date:
2019-08-15
Description:
Some Ge:Ga and Ge:Sb photoconductor materials and detectors that are currently under development are reported. The best Ge:Ga devices exhibit dark currents of lower than 200 electrons/s, with a concurrent responsivity of 2 A/W and a detective quantum efficiency (DQE) of 5 percent. For higher backgrounds, an operating temperature of 3 K can be used. This increases the DQE to 7 percent and the responsivity to 4.5 A/W. Investigations were initiated into n-type Ge:Sb as an alternative photoconductive material. Two crystals of Ge:Sb were grown and a number of test detectors were fabricated and evaluated. At 2 K, the best device produced dark currents of less than 100 electrons/s with concurrent responsivity of 1 A/W and DQE of 4 percent, and at 3 K, produced currents of 10(exp 5) electrons/s with a DQE of 7 percent and a responsivity of 4 A/W. Using p-type Ge:Ga crystals, two dimensional monolithic photoconductor arrays are being constructed. Future work will focus on measuring pixel-to-pixel homogeneity, cross talk issues, overall sensitivity and suitability for photometric instruments.
Keywords:
Spacecraft Instrumentation
Type:
The 30th ESLAB Symposium on Submillimetre and Far-Infrared Space Instrumentation; 21-24; ESA-SP-388
Format:
text
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