High-temperature long-wavelength photoconductors

Abstract

Detailed theoretical and experimental investigations of mercury-based long-wavelength narrow-band-gap semiconductor photoconductors operating in the 2OC-300 K temperature range are reported. A generalized doping-dependent figure of merit of the semiconductor, which determines the ultimate performance of the high-temperature photoconductor, is proposed. This figure of merit has been calculated for various temperatures as a function of composition and doping. Hightemperature long-wavelength photoconductors from both HgCdTe epilayers and bulk HgZnTe crystals have been fabricated and characterised. It is shown that optimised uncooled 10.6 pm photoconductors can achieve a detectivity higher than 10' cm Hz"' W", approaching the performance of slow thermal detectors.

Numerical optimization of an ambient temperature photoelectromagnetic detector for middle and far infrared spectral regions

“…Also among various variable band gap semiconductor alloys, Hg 1Àx Cd x Te is the only material covering the whole IR spectral range. MCT can be used for detection in 3-5 lm and 8-12 lm atmospheric windows which has also attracted some interest due to maximum transparency of IR wavelengths in these spectral regions [3][4][5][6]8,[12][13][14][15][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37].…”

Modeling and analysis of photoconductive detectors based on Hg1-x Cd x Te for free space optical communication

“…The performance of a photodetector depends critically on the lifetime of the photoexcited carriers. A number of excellent treatises and papers have been reported on intrinsic photoconductive and photovoltaic detectors based on Hg 1−x Cd x Te (Piotrowski et al 1990;Siliquilini 1995;Rogalski and Piotrowski 1988;Gopal 1981;Gopal 1985;Bhan and Dhar 2004;Gopal 1998;Rogalski 2005;Rogalski et al 2000). In order to achieve high sensitivity it is necessary that long wavelength infrared detectors be operated at cryogenic temperature.…”