Toughening beta-Ga2O3 via mechanically seeded dislocations

TL;DR

This paper demonstrates that introducing mechanically seeded dislocations in beta-Ga2O3 via surface scratching enhances its damage tolerance by reducing crack formation and promoting plastic deformation, addressing its intrinsic brittleness.

Contribution

The study presents a novel surface scratching method to generate dislocations in beta-Ga2O3, significantly improving its toughness and potential for flexible electronics.

Findings

Dislocations mitigate crack formation during indentation.

Surface scratching effectively introduces beneficial dislocations.

Enhanced plastic deformation reduces brittleness.

Abstract

\b{eta}-Ga2O3 is a promising candidate for next-generation semiconductors, but is limited by its intrinsic brittleness, which hinders its application in flexible electronics and high-precision devices. This study explores a new approach to improving the damage tolerance of (001)-oriented \b{eta}-Ga2O3 by introducing mechanically seeded dislocations via surface scratching. By applying a Brinell indenter to scratch the surface along the [100] direction, we effectively generate edge-type dislocations belonging to the (011)[01-1] and/or (0-11)[011] slip systems within a mesoscale wear track. Through a combination of nanoindentation tests, surface morphology analysis, and microstructural characterization using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), we reveal that the introduction of dislocations significantly mitigates the formation of cleavage cracks during indentation, in contrast to that observed in as-received \b{eta}-Ga2O3. The mechanically seeded dislocations in the subsurface layers play an important role in preventing brittle fracture by facilitating stable plastic deformation.