Mobility-electron density relation probed via controlled oxygen vacancy doping in epitaxial BaSnO₃

The recently discovered high room temperature mobility in wide band gap semiconducting BaSnO₃ is of exceptional interest for perovskite oxide heterostructures. Critical open issues with epitaxial films include determination of the optimal dopant and understanding the mobility-electron density (μ-n) relation. These are addressed here through a transport study of BaSnO₃(001) films with oxygen vacancy doping controlled via variable temperature vacuum annealing. Room temperature n can be tuned from 5 × 10¹⁹ cm⁻³ to as low as 2 × 10¹⁷ cm⁻³, which is shown to drive a weak- to strong-localization transition, a 10⁴-fold increase in resistivity, and a factor of 28 change in μ. The data reveal μ ∝ n^0.65 scaling over the entire n range probed, important information for understanding mobility-limiting scattering mechanisms.