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

We propose a device model for quantum dot infrared photodetectors (QDIPs) with relatively large lateral spacing between QDs as occurs in QDIPs fabricated 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 structural parameters, applied voltage and temperature. It explains a rather sharp increase 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 dependencies are in good agreement with available experimental data. The obtained characteristics of QDIPs are compared to those of QWIPs with similar parameters.