Extrinsic Voltage Control of Carrier Lifetime in Polycrystalline PbSe Mid-wave IR Photo Detectors for Increased Detectivity

TL;DR

This paper demonstrates that applying a back-gate voltage to polycrystalline PbSe mid-wave IR photodetectors can externally control carrier lifetime, leading to improved detectivity and potential for high-performance IR detection in low-power applications.

Contribution

It introduces an extrinsic voltage control method to modulate carrier lifetime in PbSe IR detectors, enhancing their performance and opening new design pathways.

Findings

Voltage control modulates carrier lifetime effectively.

Enhanced detector detectivity achieved through gating.

Potential for high-performance IR sensors in low-power devices.

Abstract

Polycrystalline PbSe for mid-wave IR (MWIR) photodetector is an attractive material option due to high operating/ambient temperature operation and relatively easy and cheap fabrication process, making it candidate for low-power and small footprint applications such as internet-of-thing (IoT) sensors and deployment on mobile platforms due to reduced/removed active cooling requirements. However, there are many material challenges that reduce the detectivity of these detectors. In this work, we demonstrate that it is possible to improve upon this metric by externally modulating the lifetime of conducting carriers by application of a back-gate voltage that can control the recombination rate of generated carrier. We first describe the physics of $PbSe$ detectors, the mechanisms underlying carrier transport, and long observed lifetimes of conducting carriers. We then discuss the voltage control of these inverted channels using a back-plane gate resulting in modulation of the lifetime of these carriers. This voltage control represents and extrinsic "knob" through which it may be possible to open a pathway for design of high performance IR photodetectors, as shown in this work.