Device model for quantum dot infrared photodetectors and their dark-current characteristics

We propose a device model for quantum dot infrared photodetectors (QDIPs) w ith relatively large lateral spacing between QDs as occurs in QDIPs fabrica ted and experimentally investigated recently. The developed model accounts for the self-consistent potential distribution and features of the electron capture and transport in realistic QDIPs in dark conditions. The model is used for the calculation of the dark current as a function of the structura l parameters, applied voltage and temperature. It explains a rather sharp i ncrease in the dark current with increasing applied voltage and its strong sensitivity to the density of QDs and the doping level of the active region . The calculated dependences are in good agreement with available experimen tal data. The obtained characteristics of QDIPs are compared to those of QW IPs with similar parameters.