Non-Equilibrium Devices For Infrared Detection

A non-equilibrium mode of operation for semiconductor infrared photodetectors is proposed which will enable their cooling requirements to be substantially reduced. The operating temperature of 3-5 μm band detectors may be raised from - 200K to near ambient, whilst for the 8-12 μm band devices thermoelectric coolers can be considered in place of liquified nitrogen systems. The phenomena of minority carrier exclusion and extraction are utilised in order to maintain the densities of both carrier types well below the near intrinsic, equilibrium values associated with these elevated temperatures, with consequent improvements in responsivity and D.