Lateral photocurrent spreading in single quantum well infrared photodetectors

TL;DR

This paper investigates lateral photocurrent spreading in single quantum well infrared photodetectors, deriving analytical models and discussing suppression techniques, which is crucial for improving detector spatial resolution and performance.

Contribution

It provides the first analytical expressions for responsivity and modulation transfer function considering lateral photocurrent spreading in SQWIPs.

Findings

Lateral photocurrent can spread up to 10-10000 micrometers.

Analytical formulas for responsivity and transfer function are derived.

Techniques for suppressing lateral photocurrent spreading are discussed.

Abstract

Lateral physical effects in single quantum well infrared photodetectors (SQWIPs) under non-uniform illumination over detector area are considered. These effects are due mainly to the in-plane transport of the photoinduced charge in the QW. The length of the lateral photocurrent spreading is determined by the in-plane conductivity of the carriers in the QW and characteristic time of the QW recharging, and can be as large as 10-10000 mkm. Closed-form analytical expressions for SQWIP responsivity for modulated infrared signal and modulation transfer function are obtained. Possible techniques to suppress lateral photocurrent spreading are discussed.