Room-temperature electron mobilities exceeding 130 cm²V^-1s^-1 in SrSnO₃ films

The discovery and advancement of ultra-wide bandgap (UWBG) semiconductors are of paramount importance for the development of next-generation high-power electronics. This entails the need for a UWBG semiconductor that can effectively accommodate robust doping with tunable carrier concentration and high mobility. Our study showcases the exceptional capabilities of epitaxial thin films consisting of La-doped SrSnO₃ (SSO) in meeting these requirements. Through the use of a heterostructure consisting of SSO/La:SSO/GdScO₃ (110) and the application of electrostatic gating, we have successfully disentangled electrons from their dopant atoms, resulting in a remarkable modulation of carrier density across two orders of magnitude, ranging from approximately 10¹⁸ cm^-3 to 10²⁰ cm^-3, all while maintaining room temperature mobilities between 40 and 140 cm²V^-1s^-1. Our work combines comprehensive experimental investigations and first-principles calculations to elucidate the mechanisms that limit the mobility. This study establishes SSO as a promising candidate for an emerging UWBG semiconductor, with significant potential for applications in power electronics.