High-magnitude, spatially programmable, and sustained strain engineering of 2D semiconductors

TL;DR

This paper demonstrates a method to apply stable, high-magnitude, and spatially programmable biaxial strain up to 2.2% in monolayer MoS2, enabling significant band gap tuning and advancing 2D semiconductor device engineering.

Contribution

It introduces a novel conformal transfer technique using patterned substrates to achieve stable, high-magnitude, and spatially programmable strain in 2D semiconductors.

Findings

Achieved up to 2.2% biaxial strain in monolayer MoS2

Enabled local band gap tuning of ~0.4 eV

Strain remains stable for months

Abstract

Crystalline two-dimensional (2D) semiconductors often combine high elasticity and in-plane strength, making them ideal for strain-induced tuning of electronic characteristics, akin to strategies used in silicon electronics. However, existing techniques have not achieved strain in 2D materials that is simultaneously high in magnitude (>1%), stable over long periods, and spatially programmable, meaning the strain level can be deterministically engineered across different regions of a single 2D layer. Here, we apply spatially programmable biaxial strain (e_b) up to 2.2% with spatial resolution of 0.13 %e_b um-1 in monolayer MoS2 via conformal transfer onto patterned substrates fabricated using two-photon lithography. The induced strain is stable for months and enables local band gap tuning of ~0.4 eV in monolayer MoS2, ~25% of its intrinsic band gap. We further extend the approach to bilayer WS2-MoS2 heterostructures. This strain-engineering technique introduces a new regime of strain-enabled control in 2D semiconductors to support the development of wide-spectrum optoelectronic devices and nanoelectronics with engineered electronic landscapes.