Effects of temperature and charged vacancies on electronic and optical properties of β-Ga2O3 after radiation damage

Abstract

β-Ga2O3 as an ultra-wide bandgap material is widely used in space missions and nuclear reactor environments. It is well established that the physical properties of β-Ga2O3 would be affected by radiation damage and temperature in such application scenarios. Defects are inevitably created in β-Ga2O3 upon irradiation and their dynamic evolution is positively correlated with the thermal motion of atoms as temperature increases. This work utilizes first-principles calculations to investigate how temperature influences the electronic and optical properties of β-Ga2O3 after radiation damage. It finds that the effect of p-type defects caused by Ga vacancies on optical absorption diminishes as temperature increases. The high temperature amplifies the effect of oxygen vacancies to β-Ga2O3, however, making n-type defects more pronounced and accompanied by an increase in the absorption peak in the visible band. The self-compensation effect varies when β-Ga2O3 contains both Ga vacancies and O vacancies at different temperatures. Moreover, in the case of Ga3- (O2+) vacancies, the main characters of p(n)-type defects caused by uncharged Ga0 (O0) vacancies disappear. This work aims to understand the evolution of physical properties of β-Ga2O3 under irradiation especially at high temperatures, and help analyze the damage mechanism in β-Ga2O3-based devices.