High-throughput determination of threshold displacement energies in AlGaN alloys

Abstract

Background Aluminum gallium nitride wide-bandgap semiconductors are increasing in popularity for radiation-tolerant electronic devices. Previous work determined that further research into the behavior of radiation-induced defects should be conducted to better understand the radiation damage mechanisms and improve radiation-hardening for these devices. Methods Here, molecular dynamics was combined with a first-principles-based machine learning interatomic potential and a classical Stillinger–Weber potential to systematically evaluate how the AlGaN alloy composition affects the direction-dependent threshold displacement energies. Validation was completed by performing displacements along well-researched directions. Results As aluminum concentration increases, the minimum threshold displacement energies for each type of primary knock-on atom generally rise, reaching a peak at either 50% or 75% aluminum content before declining or plateauing at higher aluminum content. The minimum threshold displacement energies range from 17–20 eV for aluminum, 16–23 eV for gallium, and 12–16 eV for nitrogen. Threshold displacement energies are dependent on the local environment surrounding the primary knock-on atom, with deviations ranging from 1.8–11.4 eV observed across sampled directions, primary knock-on atom selection, and composition. Conclusion These results provide useful insights into low-energy displacement events in AlGaN alloys. Regions of minimum threshold displacement energies were consistent for cation and nitrogen displacements across composition and between the interatomic potentials used, suggesting similar radiation-induced defect generation mechanisms. These similarities, in addition to the identified trends in threshold displacement energy values, can inform material design for radiation-hardened electronic devices.