High-Performance Mid-IR to Deep-UV van der Waals Photodetectors Capable of Local Spectroscopy at Room Temperature

TL;DR

This paper introduces a broadband, room-temperature van der Waals heterostructure photodetector capable of local spectroscopy from mid-IR to deep-UV, enabling high-resolution optical measurements without complex techniques.

Contribution

The work presents a novel 2D heterostructure photodetector with ultra-broadband sensitivity, high detectivity, and submicron active areas for nanoscale optical spectroscopy.

Findings

Detectivity > 10^9 cm Hz^1/2 W^-1

Bandwidth of 2.1 MHz

Submicron active area for local measurements

Abstract

The ability to perform broadband optical spectroscopy with sub-diffraction-limit resolution is highly sought-after for a wide range of critical applications. However, sophisticated tip-enhanced techniques are currently required to achieve this goal. We bypass this challenge by demonstrating an extremely broadband photodetector based on a two-dimensional (2D) van der Waals heterostructure that is sensitive to light across over a decade in energy from the mid-infrared (MIR) to deep-ultraviolet (DUV) at room temperature. The devices feature high detectivity (> 10^9 cm Hz^1/2 W^-1) together with high bandwidth (2.1 MHz). The active area can be further miniaturized to submicron dimensions, far below the diffraction limit for the longest detectable wavelength of 4.1 um, enabling such devices for facile measurements of local optical properties on atomic-layer-thickness samples placed in close proximity. This work can lead to the development of low-cost and high-throughput photosensors for hyperspectral imaging at the nanoscale.