Characteristics of uncooled indium antimonide photoconductors

Uncooled indium antimonide (InSb) photoconductors were studied to determine their primary noise source, spectral response, and maximum attainable spectral detectivity. The dominant noise component was determined by theoretically analyzing the background photon generation- recombination noise, thermal generation-recombination noise, and Johnson noise, using conditions of the experimental setup. It was shown that at room temperature (300 K) Johnson noise was predominant. Using this fact, an expression was derived for spectral detectivity which gave a value of 1.3 X 108 cm-Hz1/2/watt for a 25.2 k(Omega) photoconductor and 5.9 X 108 cm-Hz1/2/watt for a 10 k(Omega) photoconductor. The measurements from the experiment showed a peak wavelength response at 5 micrometer and a cutoff wavelength (50% of maximum) at 5.5 micrometer. The average peak spectral detectivity for the 25.2 k(Omega) photoconductor was 1.17 X 108 cm- Hz1/2/watt and for the 10 k(Omega) photoconductor, 4.48 X 108 cm- Hz1/2/watt. These results compared well with theory.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.