Dark current caused by the field-induced mixing effect on bound-to-continuum quantum-well infrared photodetectors

Different from the single-barrier Wentzel-Kramer-Brillouin tunnelling and thermionic emission models, the dark current of bound-to-continuum quantum-well infrared photodetectors is theoretically studied by the new approach of the field-induced mixing effect (FIME). Based on the rate balance condition between the loss rate of bound electrons caused by FIME and the net quantum capture of continuum electrons, the Fermi levels of continuum and bound electrons are separated with each other at non-zero bias. In addition to showing good agreement with the experimental results without parameter fitting techniques, the variations of dark current with both operating temperature and voltage bias can also be explained by the Fermi level of continuum electrons. With a current suppression ratio to reveal the variations of dark current with structural parameters, the ratio and the temperature region where the dark current is effectively suppressed are both diminished as the bias increases.