High field-effect mobility at the (Sr,Ba)SnO₃/BaSnO₃ interface

A perovskite oxide, BaSnO₃, has been classified as one of transparent conducting materials with high electron mobility, and its application for field-effect transistors has been the focus of recent research. Here we report transistor operation in BaSnO₃-based heterostructures with atomically smooth surfaces, fabricated on SrTiO₃ substrates by the (Sr,Ba)SnO₃ buffer technique. Indeed, modulation of band profiles at the channel interfaces with the insertion of wide bandgap (Sr,Ba)SnO₃ as a barrier layer results in a significant improvement of field-effect mobility, implying effective carrier doping at the regulated heterointerface. These results provide an important step towards realization of high-performance BaSnO₃-based field-effect transistors.