GaAs/AlGaAs Nanowire Photodetector

TL;DR

This paper reports a room-temperature GaAs/AlGaAs nanowire photodetector with high responsivity and detectivity, utilizing a heterostructure and MSM architecture to enhance charge separation and optical resonance.

Contribution

It introduces a novel core-shell GaAs/AlGaAs nanowire photodetector with optimized heterostructure and architecture for improved photodetection performance at near-infrared wavelengths.

Findings

Peak photoresponsivity of 0.57 A/W

High detectivity of 7.2×10^10 cm√Hz/W

Supports resonant optical modes in near-infrared

Abstract

We demonstrate an efficient core-shell GaAs/AlGaAs nanowire photodetector operating at room temperature. The design of this nanoscale detector is based on a type-I heterostructure combined with a metal-semiconductor-metal (MSM) radial architecture, in which built-in electric fields at the semiconductor heterointerface and at the metal/semiconductor Schottky contact promote photogenerated charge separation, enhancing photosensitivity. The spectral photoconductive response shows that the nanowire supports resonant optical modes in the near-infrared region, which lead to large photocurrent density in agreement with the predictions of electromagnetic and transport computational models. The single nanowire photodetector shows remarkable peak photoresponsivity of 0.57 A/W, comparable to large-area planar GaAs photodetectors on the market, and a high detectivity of 7.2 10^10 cm\sqrt{Hz}/W at {\lambda}=855 nm. This is promising for the design of a new generation of highly sensitive single nanowire photodetectors by controlling optical mode confinement, bandgap, density of states, and electrode engineering.