Self-powered InP Nanowire Photodetector for Single Photon Level Detection at Room Temperature

TL;DR

This paper presents a room-temperature, self-powered InP nanowire photodetector capable of single-photon detection without external bias, combining broadband sensitivity, low dark current, and high-speed operation for advanced optical technologies.

Contribution

The authors demonstrate a novel self-powered InP nanowire photodetector achieving single-photon detection at room temperature without external bias, using a radial p-n junction with high electric field.

Findings

Detects single photons at room temperature without external bias

Achieves broadband sensitivity and high-speed operation above 600 MHz

Exhibits extremely low dark current and high charge separation efficiency

Abstract

Highly sensitive photodetectors with single photon level detection is one of the key components to a range of emerging technologies, in particular the ever-growing field of optical communication, remote sensing, and quantum computing. Currently, most of the single-photon detection technologies require external biasing at high voltages and/or cooling to low temperatures, posing great limitations for wider applications. Here, we demonstrate InP nanowire array photodetectors that can achieve single-photon level light detection at room temperature without an external bias. We use top-down etched, heavily doped p-type InP nanowires and n-type AZO/ZnO carrier selective contact to form a radial p-n junction with a built-in electric field exceeding 3x10^5 V/cm at 0 V. The device exhibits broadband light sensitivity and can distinguish a single photon per pulse from the dark noise at 0 V, enabled by its design to realize near-ideal broadband absorption, extremely low dark current, and highly efficient charge carrier separation. Meanwhile, the bandwidth of the device reaches above 600 MHz with a timing jitter of 538 ps. The proposed device design provides a new pathway towards low-cost, high-sensitivity, self-powered photodetectors for numerous future applications.