Deterministic Realization of Complex Local Strain Fields and Bandgap Profiles in Two-Dimensional Materials

TL;DR

This paper presents a deterministic, geometry-based method for controlling local strain and bandgap profiles in 2D materials, validated through experiments and modeling, enabling precise optoelectronic property engineering.

Contribution

The authors introduce a material-agnostic platform using nanostructure geometry to predict and control strain and bandgap distributions in 2D materials with high accuracy.

Findings

Hyperspectral photoluminescence mapping quantifies strain-to-bandgap relations.

A two-component analytical model predicts bandgap shifts with less than 12% error.

The approach is extendable to other 2D materials.

Abstract

Emerging classical and quantum device concepts demand precise spatial control over the optoelectronic properties of two-dimensional (2D) materials, but deterministic engineering via local multiaxial strain distributions remains challenging. Using Ga$_2$Se$_2$, we demonstrate a material-agnostic platform in which nanostructure geometry deterministically prescribes in-plane strain profiles in suspended van der Waals membranes. We first use hyperspectral photoluminescence mapping and experimentally-constrained finite element analysis to quantify the experimental biaxial and uniaxial strain gauge factors that relate strain to the change in bandgap. We next show that a two-component analytical model can predict, with less than 12% error, spatially-resolved bandgap shifts arising from multiaxial strain distributions in complex geometries, including the interactions between adjacent nanostructures. Finally, we demonstrate that this approach can be extended to other materials. The results demonstrate that nanostructure design provides a quantitative, deterministic framework for the realization of designed strain and bandgap distributions in 2D materials.