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

Tristan K Truttmann,I-Te Lu,Thomas E Mates,Jin-Jian Zhou,Marco Bernardi,Anil Kumar Rajapitamahuni,Fengdeng Liu,Bharat Jalan

doi:10.1038/s42005-021-00742-w

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 NdxSr1−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.

Highlights

The discovery and development of ultra-wide bandgap (UWBG) semiconductors is crucial to accelerate the adoption of renewable power sources
In the example of blue lightemitting diodes (LEDs), GaN lacked lattice-matched substrates and failed to show p-type conductivity upon early doping attempts[1]. These challenges deterred the vast majority of LED researchers, who instead opted to study II–VI semiconductors which—despite obvious degradation problems—were attractive because they could be grown with high structural quality, achieve ambipolar doping, and be made into working devices—albeit short-lived ones[2]
Of the SSO films grown by pulsed laser deposition (PLD), the best dopant activation reported was 70% of the La dopants which was only possible after post-growth annealing[6]

Summary

Introduction

The discovery and development of ultra-wide bandgap (UWBG) semiconductors is crucial to accelerate the adoption of renewable power sources. This work explores the mobility-limiting mechanisms in one such under-investigated UWBG semiconductor, SrSnO3 (SSO), by combining experiments and computation.

Results

Conclusion