Hybrid Molecular Beam Epitaxy and Electronic Transport of Alkaline Earth Stannates

Perovskite oxides have been the subject of intense ongoing study due to the diverse assortment of available properties and phenomena that they and their derivatives exhibit. However, until recently, there has been an unfilled gap for perovskite oxides that exhibit a high carrier mobility at room temperature. This gap was filled with the discovery of BaSnO₃ single crystals exhibiting room-temperature electron mobilities as high as 320 cm²V^-1s^-1. Here we present the growth of epitaxial thin-films of BaSnO₃ and its noncubic analogs through the A-site substitution of Ba with smaller Sr and Ca. This includes a systematic doping study of SrSnO₃ over a wide range of carrier concentrations with record room-temperature electron mobilities exceeding 70 cm²V^-1s^-1, and the first ever growth of CaSnO₃ by molecular beam epitaxy, whose ultrawide bandgap make it an encouraging ultra-wide bandgap material for applications in high-power devices and novel heterostructure-based transistors combining other functional perovskite oxides.