Dark current mechanism and the cause of the current-voltage asymmetry in quantum-well intersubband photodetectors

Recent research activity in the long wavelength infrared spectral region has been driven by the wide range of possible applications for optoelectronic systems and by the wealth of new physical phenomena displayed by quantum well intersubband-based devices. GaAs-AlGaAs quantum well intersubband photodetectors are currently under intense research investigation, and promise to have a wide range of application. Here we first present a microscopic model of the detector dark current, which provides new physical insights into the mechanism of carrier transport in multiple quantum well structures. Systematic experiments have been carried out to compare with the model, and good agreement between theory and experiments is obtained. The model is based on considering the details of the carrier trapping and emission from quantum wells.