2D GaSe-Based Single-Pixel Spectrometer via Electro-Optical Barrier Co-Modulation

TL;DR

This paper introduces a compact, high-resolution single-pixel spectrometer using a 2D GaSe photodetector that encodes spectral information via electro-optical barrier modulation, suitable for portable applications.

Contribution

The authors demonstrate a novel GaSe-based spectrometer that achieves high spectral accuracy and resolution without bulky dispersive elements, enabling miniaturized on-chip spectral sensing.

Findings

Peak-wavelength accuracy of ~0.78 nm across 300-700 nm

Spectral resolution down to ~5 nm separation

Operates at low bias with ultralow dark current

Abstract

Driven by the growing demand for miniaturized spectrometers for in-situ analysis, and point-of-care diagnostics, conventional spectrometers are often constrained by bulky architectures and pathlength-limited spectral resolution. Achieving high-resolution, single-pixel computational spectrometers is therefore critical for the realization of compact, on-chip systems. Here, we report a single-pixel spectrometer enabled by a single 2D material; few-layer GaSe-based photodetector, in which the Schottky barrier height modulation, governed jointly by applied bias and optical excitation, provides an efficient mechanism for spectral encoding without the need for bulky dispersive elements. The device exhibits a high peak-wavelength accuracy of ~0.78 nm across a broad operational bandwidth (300-700 nm) within a compact footprint of ~100 um^2 and resolves closely spaced spectral features with separations down to ~5 nm. The device operates at low bias (+/- 4V) with an ultralow dark current density ~0.3 pA/um^2 at 4V bias. These results establish a simple, scalable route toward compact, cost-effective spectroscopic systems for on-chip spectral sensing and portable hyperspectral imaging applications.