Examining composition-dependent radiation response in AlGaN

TL;DR

This study uses molecular dynamics simulations to explore how the composition of AlGaN alloys affects radiation-induced defect formation, revealing that 25% Al content minimizes damage and informing strategies for radiation-resistant materials.

Contribution

It provides the first detailed atomistic analysis of how alloy composition influences radiation damage mechanisms in AlGaN, bridging simulation and experimental data.

Findings

Defect production decreases with higher Al content from individual recoil events.

Extended interstitial defects become more prevalent at higher doses with increased Al.

25% Al composition results in the least overall radiation damage.

Abstract

Al$_x$Ga$_{1-x}$N materials have become increasingly important for electronics in radiation environments due to their robust properties. In this work, we aim to investigate the atomistic mechanisms of radiation-induced damage in AlGaN compounds, providing insights that bridge the gap between high-length-scale experimental data and detailed atomic-level processes. Through extensive molecular dynamics simulations, we reveal the compositional dependence of radiation-induced defect production in Al$_x$Ga$_{1-x}$N systems with $x$ ranging from 0 to 1. The damage accumulation characteristics observed in our simulations align notably well with available experimental data at temperatures up to room temperature. Our findings indicate that alloy composition significantly influences defect production and microstructural evolution, including the formation of dislocation loops and defect clusters. Specifically, with increasing Al content, defect production from individual recoil events is reduced; however, extended interstitial defects are more likely to form considering cumulative effects, leading to enhanced damage at high doses. Among the compositions studied, we find that 25\% Al content leads to the least overall radiation damage, suggesting an optimal alloying strategy for mitigating radiation effects. These findings underscore the interplay between defect formation, dynamic annealing, and cascade effects, offering insights for optimizing AlGaN materials for radiation resistance in practical applications.