Physical model and analysis of quantum dot infrared photodetectors with blocking layer

A device model for quantum dot infrared photodetectors (QDIPs) with the blocking layer (BL) between quantum dots is presented. Explicit analytical formulas for the dark current and the responsivity in the QDIP of this type are obtained as functions of device parameters, including the doping level of the QDIP active region, and the applied bias voltage. It is shown that there are three voltage ranges in which the dark current and the responsivity of QDIPs reveal different behavior. The obtained results qualitatively explain some features of the QDIPs with BL observed experimentally. The characteristics of the QDIPs under consideration are compared with those of other detectors. (C) 2001 American Institute of Physics.