Photo-degradation Protection in 2D In-Plane Heterostructures Revealed by Hyperspectral Nanoimaging: the Role of Nano-Interface 2D Alloys

TL;DR

This study reveals that 2D alloyed interfaces in MoS2-WS2 heterostructures enhance stability against photo-degradation, offering insights into protecting 2D materials for optoelectronic applications.

Contribution

The paper introduces a liquid-phase synthesis method for 2D in-plane heterostructures with nanoscale alloyed interfaces and demonstrates their enhanced degradation resistance using advanced hyperspectral imaging.

Findings

Alloyed regions show increased stability against photo-degradation.

Localized potential wells in alloy regions concentrate excitons.

Alloy interfaces provide protection against oxidation.

Abstract

Single-layer heterostructures exhibit striking quasiparticle properties and many-body interaction effects that hold promise for a range of applications. However, their properties can be altered by intrinsic and extrinsic defects, thus diminishing their applicability. Therefore, it is of paramount importance to identify defects and understand 2D materials' degradation over time using advanced multimodal imaging techniques as well as stabilize degradation via built-in interface protection. Here we implemented a liquid-phase precursor approach to synthesize 2D in-plane MoS2-WS2 heterostructures exhibiting nanoscale alloyed interfaces and map exotic interface effects during photo-degradation using a novel combination of hyperspectral tip-enhanced photoluminescence, Raman and near-field nanoscopy. Surprisingly, 2D alloyed regions exhibit remarkable thermal and photo-degradation stability providing protection against oxidation. Coupled with surface and interface strain, 2D alloy regions create localized potential wells that concentrate excitonic species via a charge carrier funneling effect. These results provide a clear understanding of the importance of 2D alloys as systems able to withstand degradation effects over time, and could be now used to stabilize optoelectronic devices based on 2D materials.