Oxygen vacancy engineering in pulsed laser deposited BaSnO3 thin films on SrTiO3

We demonstrate the tunability of the oxygen content in pulsed laser deposition-grown barium stannate thin films (BaSn O3, BSO) by precisely controlling the background oxygen pressure over a broad range from 0.0004 to 0.13 mbar. The introduction of oxygen vacancies (OV) significantly alters the structural properties of BSO films, inducing a monotonic expansion of the out-of-plane lattice parameter and cell volume as the vacancy concentration increases. The progressive formation of OV was spectroscopically tracked using x-ray photoelectron spectroscopy, providing direct insight into the vacancy evolution. Furthermore, we show that the oxygen stoichiometry in BSO plays a critical role in modulating the sheet resistance of BSO/LaScO3 heterostructures, enabling interface metallic electron conduction. This oxygen content control offers a robust strategy to tailor the electronic properties at the interface, highlighting its potential for oxide electronics and functional interface engineering.