Modeling of dark current in mid-infrared quantum-well infrared photodetectors

Optimization of dark current is a key technological issue to be addressed in order to improve quantum-well infrared photodetector (QWIP) performance. We develop a model for the description of current–voltage curves in mid-infrared QWIPs, which usually span a range of electric fields in which both low-field as well as high-field carrier transport effects are visible, especially at low temperatures. The model separates the I–V curve into a low-field and a high-field region allowing us to identify and separate the effects ascribed to miniband transport and carrier localization, respectively. We then compare simulations with our measurements of the I–V curves of mid-ir QWIPs finding a good quantitative agreement between theory and experiment.