Exploration of novel InSbBi alloy for uncooled infrared photodetector applications

In this paper, we report on the growth and investigation of InSbBi alloy fo r uncooled infrared photodetector applications. The epitaxial layers were g rown on InSb and GaAs substrates by low pressure metalorganic chemical vapo r deposition. The incorporation of Bi was verified by various techniques su ch as high resolution x-ray diffraction, energy dispersive x-ray analysis, and infrared photoresponse measurements. The maximum incorporation of Pi es timated from the optical band gap change was 5.8 %. Preliminary photoconduc tive detectors based on this material are reported. The responsivity of an InSb0.96Bi0.04 photodetector at 7 mu m was about 3.2 V/W at 77 K with corre sponding Johnson noise limited detectivity of 4.7x10(8) cmHz(1/2)/W. The ca rrier lifetime of an InSb0.96Bi0.04 detector was estimated to be about 86 n s from the voltage dependent responsivity measurements. Room temperature op erating 8-12 mu m InSb0.95Bi0.05 photodetector was also demonstrated. The v oltage responsivity at 10.6 mu m was about 1.9 mV/W at room temperature and the corresponding Johnson noise limited detectivity was estimated to be ab out 1.2x10(6) cmHz(1/2)/W.