Designing inorganic semiconductors with cold-rolling processability

TL;DR

This paper demonstrates that by compositional design, inorganic semiconductors can be made processable by cold rolling, enabling flexible electronics applications, with systematic calculations and experimental validation showing successful material modifications.

Contribution

It introduces a method to tailor fracture toughness in inorganic semiconductors, enabling cold rolling processability, supported by ab initio calculations and experimental confirmation.

Findings

GaSe can be cold rolled to large thickness reductions

Material-property maps predict trends in slip susceptibility and fracture toughness

Design strategies enable flexible electronic applications

Abstract

While metals can be readily processed and reshaped by cold rolling, most bulk inorganic semiconductors are brittle materials that tend to fracture when plastically deformed. Manufacturing thin sheets and foils of inorganic semiconductors is therefore a bottleneck problem, severely restricting their use in flexible electronics applications. It was recently reported that a few single-crystalline two-dimensional van der Waals (vdW) semiconductors, such as InSe, are deformable under compressive stress. Here we demonstrate that intralayer fracture toughness can be tailored via compositional design to make inorganic semiconductors processable by cold rolling. We report systematic ab initio calculations covering a range of van der Waals semiconductors homologous to InSe, leading to material-property maps that forecast trends in both the susceptibility to interlayer slip and the intralayer fracture toughness against cracking. GaSe has been predicted, and experimentally confirmed, to be practically amenable to being rolled to large (three quarters) thickness reduction and length extension by a factor of three. Our findings open a new realm of possibility for alloy selection and design towards processing-friendly group-III chalcogenides for flexible electronic and thermoelectric applications.