Self-consistent model for quantum well infrared photodetectors with thermionic injection under dark conditions

Abstract

We present a self-consistent analytical model describing transport processes in quantum well infrared photodetectors (QWIPs) under dark conditions. The model takes into account electron thermionic emission from the quantum wells, thermionic injection from the emitter contact, and features of transport and capture in the self-consistent electric field in the QWIP active region. Using an assumption that the rates of the electron escape from and capture into a QW are functions of the electric fields only in the barriers sandwiching this QW, we calculate the electric field and charge distributions as well as dark current–voltage characteristics. We clarify the origin of steep dark current characteristics. It is confirmed that the effect of the emitter contact substantially weakens with increasing number of QWs in the QWIP structure.