Wide Bandgap Perovskite Oxides with High Room-Temperature Electron Mobility

Perovskite oxides are ABO₃-type compounds with a crystal structure capable of accommodating a large number of elements at A- and B-sites. Owing to their flexible structure and complex chemistry, they exhibit a wide range of functionalities as well as novel ground states at the interface. However, in comparison with conventional semiconductors such as silicon, they possess orders of magnitude lower room-temperature electron mobilities limiting their room-temperature electronic applications. For example, in a prototypical doped SrTiO₃, the room-temperature electron mobility remains below 10 cm² V⁻¹ s⁻¹ regardless of the defect minimization. Discovery of high room-temperature mobility in alkaline-earth stannates such as BaSnO₃ and SrSnO₃ constitutes a significant advancement toward all-perovskite electronic and spintronic devices. Alkaline-earth stannates also possess wide-to-ultra wide bandgaps that make them potentially suitable candidate for transparent conductors, power electronic devices, and high electron mobility transistors. This article provides an overview of the recent progress made to these materials' electrical properties with particular emphasis on the advancements in the molecular beam epitaxy approaches for their synthesis, and defect control.