Exploring the influence of oxygen vacancy on the transport behavior of Ba_1-xLa_xSnO₃ epitaxial films at different doping regimes

La-doped BaSnO3 (BLSO) exhibits promising applications in oxide electronic devices, owing to its high electron mobility and good thermal stability. The introduction of extrinsic La dopants could actively interact with the formation of intrinsic oxygen vacancies in BLSO films, which collectively influence the resulting transport behavior. However, it is not clear which factor plays a dominant role when the La dopant ratio varies. Here, we fabricate BLSO films at lightly doped (0.2%) and heavily doped (7%) regimes and perform a systematic investigation on the oxygen vacancy impact on structure, optical, and transport properties of these BLSO films. It is revealed that the BLSO films grown at an ozone environment show larger strain and lower oxygen vacancy concentrations for all investigated dopant ratios. More importantly, the introduction of ozone decreases the mobility and the carrier concentration of both lightly doped and heavily doped films. This study reveals that the presence of oxygen vacancies enhances the carrier concentration and electron mobility, which is independent of the La dopant ratio, and provides an effective strategy for optimizing the electrical properties of BLSO films.