Comparison of Ultimate Limits of Interband Cascade Infrared Photodetectors and Single-Absorber Detectors

摘要

A comparison of the ultimate limits of multiple-stage interband cascade infrared photodetectors (ICIPs) with standard single-absorber photovoltaic infrared detectors is presented. In particular, we focus on how the multiple-stage architecture can offer an improvement in sensitivity over single-absorber detectors in situations where the latter detector type is limited by a low photocarrier collection efficiency. A general overview of the ICIP architecture and its benefits in carrier collection improvement, and noise reduction is presented. The developed theory is then applied to compare single- and multiple-stage detectors operating in the strong signal regime. It is found that if ICIPs are designed with photocurrent-matched absorbers, the signal-to-noise ratio depends on the total particle conversion efficiency of the device. The potential benefits of the ICIP architecture are shown to be greatest when the quantum efficiency of singleabsorber detectors is limited by poor photo-carrier extraction.