Recent progress in HgCdTe infrared detector technology

At present effors in infrared (IR) detector ressearch are directed towards improving the performance of single element devices and large electronically scanned arrays, and to increase their operating temperature. Another important aim is to make IR detectors cheaper and more convenient to use. Among different types of materials used in IR detector technology, HgCdTe ternary alloy has privileged position. HgCdTe remains the most important material for infrared photodetectors despite of numerous attempts to replace it with alternative materials. None of these competitors can compete in terms of fundamental properties. In addition, HgCdTe exhibits nearly constant lattice parameter that is of extreme importance for new devices based on complex heterostructures. In the paper investigations of the performance of HgCdTe photodiodes operated at short wavelength IR (SWIR), 1-3 um ; medium wavelength IR (MWIR), 3-5 um ; and long wavelength IR (LWIR), 8-14 um spectral regions are presented. The operating temperature for HgCdTe detectors is hogher than for other types of photo detectors. HgCdTe detectors with background limited performance operate with thermoelectric coolers in the medium wavelength range, while the long wavelenght detectors operate at ≈100 K. HgCdTe is haracterized by high absorption coefficient and quantum efficiency and relatively low thermal generation rate compared to other detectors. Despite serious competition from alternative technologies and slower progress than expected, HgCdTe is unlikely to by seriously challenged for high-performance applications, applications requiring multispectral capability and fast response. The long term picture could change as a result of current research activity in low-cost, lightweight, small in size and convenient to use of uncooled detectors.