Gate-Tunable Mid-Infrared Electroluminescence from Te/MoS2 p-n Heterojunctions

TL;DR

This paper reports a gate-tunable mid-infrared light-emitting diode using a Te/MoS2 heterojunction, demonstrating stable, polarized emission at 3.5 μm suitable for integrated optoelectronic applications.

Contribution

It introduces a novel Te/MoS2 heterostructure device with gate-controlled tunable mid-infrared electroluminescence, advancing 2D material-based MIR emitters.

Findings

Emits polarized EL at 3.5 μm under 25 K

EL persists up to 80 K with reduced intensity

Gate tuning modulates EL intensity via band alignment

Abstract

Mid-infrared (MIR) emitters are critical components in advanced photonic systems, driving progress in fields such as chemical sensing, environmental monitoring, medical diagnostics, thermal imaging and free-space communications. Conventional MIR emitters based on III-V heterostructures rely on complex epitaxial growth on rigid lattice-matched substrates and suffer from limited integration compatibility with CMOS or flexible platforms. The recent development of novel MIR emitters based on two-dimensional (2D) materials such as black phosphorus (BP) is more suitable for on-chip applications but faces challenges related to stability and emission efficiency. Based on the recently discovered highly efficient photoluminescence of Te, we demonstrate a gate-tunable midinfrared light-emitting diode based on a van der Waals heterojunction formed by multilayer transition metal dichalcogenide (TMD) MoS2 and tellurium (Te). The device emits polarized electroluminescence (EL) centered at 3.5 $\mu$m under forward bias at 25 K, and the EL persists up to 80 K with reduced intensity. Gate control of the MoS2 Fermi level modulates the band alignment and injection efficiency, enabling dynamic tuning of the EL intensity. The emission remains spectrally stable under varying bias and gating, indicating robust band-edge recombination. These results establish the Te/TMD heterostructure as a promising platform for integrated polarized mid-infrared optoelectronics.