Prospects for high carrier mobility in the cubic germanates

Abstract

High-mobility wide-band-gap oxides are essential materials for device applications in high-frequency and power electronics. We use first-principles calculations to evaluate the potential of two cubic perovskite germanates, SrGeO3 and BaGeO3, for these applications. We find their effective masses to be small, both for electrons and holes. The prospect of p-type conductivity renders the germanates attractive for complementary metal-oxide-semiconductor technology. We calculate the electron drift mobility in SrGeO3 to lie between 400 and 500 cm2V−1s−1 for a range of accessible carrier concentrations; this mobility is as much as 50% larger than in BaSnO3, which has the highest room-temperature electron mobility among perovskite oxides. Our results suggest that the germanates hold promise for high-mobility electronic applications.