Work

Multiscale Explanation of the Missing Gallium Vacancy in Gallium Arsenide

Year: 2025

Type: article

Abstract: Irradiation of gallium arsenide (GaAs) produces immobile vacancies and mobile interstitials. Yet, after decades of experimental investigation, the immobile Ga vacancy continues to evade detection, raising the question: where is the Ga vacancy? Static first-principles calculations predict a Ga vacancy should be readily observed. We find that short-time dynamical evolution of primary defects is the key to explaining this conundrum. Using a dynamical multiscale atomistically informed device engineering (AIDE) method, we discover that during the initial displacement damage, the Ga vacancy (3-/2-) defect level pins the Fermi level near the midgap, producing oppositely charged vacancies and interstitials. Driven by Coulomb attraction, fast As interstitials preferentially annihilate Ga vacancies. The Ga vacancy population plummets below detectable limits-and the now unpinned Fermi level recovers-before being experimentally observed. This dynamical model solves the mystery of the missing Ga vacancy and reveals the importance of a multiscale approach to explore the dynamical chemical behavior in experimentally inaccessible short-time regimes.

Source: Physical Review Letters

DOI: 10.1103/scn4-2wmv

Authors: Leopoldo Diaz, Harold P. Hjalmarson, Jesse J. Lutz, Peter A. Schultz

Institutions: Sandia National Laboratories California, Sandia National Laboratories

Language: English

Topic: Semiconductor materials and interfaces

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,750

Funders: U.S. Department of Energy, Honeywell, Laboratory Directed Research and Development