First-principles study on the magnetism, carrier activity, and carrier lifetime of Ga2O3: Li or Na or K with different valence Ga vacancies and H interstitial

Abstract

A first-principles study is conducted by using the generalized gradient approximation within the framework of density functional theory, with the plane wave ultrasoft pseudopotential + U method. We investigate the effects of formation energy, magnetism, and photocatalytic performance in Ga30MO48 (VGa0/VGa1−/VGa2−/VGa3−, M = Li or Na or K) and Ga30MHiO48 (VGa0/VGa1−/VGa2−/VGa3−) systems. Results indicate that under O-rich conditions, the formation energy (Ef) is lower, making the systems more stable and easily doped. The Ga30MHiO48 (VGa0/VGa1−/VGa2−/VGa3−) system exhibits a relatively lower Ef than Ga30MO48 (VGa0/VGa1−/VGa2−/VGa3−). The magnetic source of the doping systems is primarily contributed by O1− ions near Ga vacancies. The Ga30KHiO48 (VGa1−) system exhibits good carrier activity, the longest electron–hole lifetime, noticeable light absorption, and strong reduction capability, making it a promising photocatalyst for H2 production.