Novel Sb-based materials for uncooled infrared photodetector applications

We have developed low-pressure metalorganic chemical vapor deposition technology for the growth of novel III-V Sb-based compounds such as InTlSb, InTlAsSb, and InSbBi. The incorporation of Tl and Bi is investigated with various characterization techniques. Preliminary infrared photodetectors based on these materials are fabricated and tested. The maximum responsivity of an In_0.96Tl_0.04Sb photodetector is about 6.64 V/W at 77 K, corresponding to a Johnson-noise-limited detectivity of about 7.64×10⁸ cm Hz^1/2/W. Photoresponse of the In_0.94Tl_0.06Sb photodetector has been extended to 11 μm at 300 K. Infrared photoresponse up to 15 μm is achieved from the InTlAsSb alloy at room temperature. We also demonstrate the uncooled InSbBi photodetector operating in the 8-12 μm range. The voltage responsivity at 10.6 μm is about 1.9 mV/W at 300 K and the corresponding Johnson-noise-limited detectivity is 1.2×10⁶ cm Hz^1/2/W. The carrier lifetime is estimated to be 0.7 ns.