Mobility modulation effects in a double quantum well infrared photon-detector

TL;DR

This paper investigates a double quantum well infrared photon-detector and reports the novel observation of negative photon-response caused by photon-induced charge effects reducing electron mobility.

Contribution

It introduces the phenomenon of negative photon-response in a double quantum well detector and clarifies its origin as a mobility reduction due to photon-induced charges.

Findings

Negative photon-response observed in the detector

Photon-induced charges reduce electron mobility

Clarification of the response mechanism

Abstract

An electrically isolated quantum well (QW) island can be positively charged by incoming infrared photon, because its electrons absorb photon energy via intersubband transition and acquire enough energy to escape it. This process has been used in a double QW photon-detector. Here, we present the observation of so-called negative photon-response in such detector. Its origin is clarified to be an electron mobility reduction phenomenon resulted from the photon induced charges.