Growth of InTlSB and InTlP for Long Wavelength Infrared Detector Applications
Final technical rept. Jun 92-Dec 98
NORTHWESTERN UNIV EVANSTON IL CENTER FOR QUANTUM DEVICES
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The objective of this research is to develop room temperature operating long-wavelength infrared LWIR photodetectors with novel III-V alloys. For the first time, we have successfully demonstrated the growth of InTlSb, InTlP, and InTlAsSb alloys by low-pressure metalorganic chemical vapor deposition. Other novel alloys such as InAsSb and InSbBi are also investigated. The structural, optical, and electrical properties of these novel materials have been investigated in detail with various ex-situ characterization techniques. For the first time, preliminary LWIR InTlSb photodetectors on GaAs are fabricated with the grown materials and device performance has been characterized. The InTlSb photoconductor showed 11 microns cutoff wavelength at room temperature. The Johnson-noise limited detectivity is estimated to be in the range of 10exp 6-10exp 7 cmHz12W. The carrier lifetime is derived from the voltage-dependent responsivity, which is in 0.1-0.6 ns at 300 K. Photoconductivity measurements on InTlPInP indicate an increase of the cutoff wavelength up to 8 microns with increasing Tl incorporation. Recently, we have observed LWIR photoconductivity up to 15 microns at room temperature by incorporating Tl into InAsSb. These results clearly show the feasibility of using III-V alloys for LWIR photodetector applications as an alternative to HgCdTe detectors.
- Infrared Detection and Detectors
- Solid State Physics