Combined experimental-theoretical study of electron mobility-limiting mechanisms in SrSnO3

Abstract

The discovery and development of ultra-wide bandgap (UWBG) semiconductors is crucial to accelerate the adoption of renewable power sources. This necessitates an UWBG semiconductor that exhibits robust doping with high carrier mobility over a wide range of carrier concentrations. Here we demonstrate that epitaxial thin films of the perovskite oxide Nd_xSr_1−xSnO₃ (SSO) do exactly this. Nd is used as a donor to successfully modulate the carrier concentration over nearly two orders of magnitude, from 3.7 × 10¹⁸ cm⁻³ to 2.0 × 10²⁰ cm⁻³. Despite being grown on lattice-mismatched substrates and thus having relatively high structural disorder, SSO films exhibited the highest room-temperature mobility, ~70 cm² V⁻¹ s⁻¹, among all known UWBG semiconductors in the range of carrier concentrations studied. The phonon-limited mobility is calculated from first principles and supplemented with a model to treat ionized impurity and Kondo scattering. This produces excellent agreement with experiment over a wide range of temperatures and carrier concentrations, and predicts the room-temperature phonon-limited mobility to be 76–99 cm² V⁻¹ s⁻¹ depending on carrier concentration. This work establishes a perovskite oxide as an emerging UWBG semiconductor candidate with potential for applications in power electronics.

Semiconductor research is undergoing transformative changes thanks to the discovery and development of novel materials. The authors disclose the role of electron-phonon interaction and impurity scattering in a novel ultrawide bandgap perovskite oxide, paving the way for new applications in high-power electronics.