Temperature-insensitive detectivity infrared photodetectors with of 5-pair InAs/GaAs quantum-dot asymmetric device structure

In this paper, 5-pair InAs/GaAs QDIPs with tunable dark current blocking barrier resulting from a p-type doped GaAs layer are fabricated. With a proper choice of the p-type doping density, temperature-insensitive detectivities up to 110 K at low applied voltage 0.8 V are obtained. The phenomenon is attributed to the one order of magnitude increase of photocurrent with increasing temperature resulting from the increase of transition probability with more available empty excited states at higher temperature. The results have shown superior high-temperature operation of the asymmetric QDIP structure than the symmetric device. (c) 2006 Elsevier B.V. All rights reserved.