Modeling of a quantum well infrared detector with a dark current discriminator

Abstract

A model is developed to provide estimates of the performance of quantum well intersubband infrared photodetectors. By introducing an energy filter to reduce the dark current, the quantum well device performance is improved. The amount of reduction in dark current depends upon the height of the energy filter barrier which can be varied by bias voltage. The energy distributions of the dark current and photocurrent electrons are discussed. Calculated results are presented for detectors with different quantum well widths, including the cases of bound-to-bound and bound-to-continuum transitions. The reduction in dark current results in a higher detectivity, and a substantial improvement over traditional designs can be obtained for some well widths.