The influence of in situ ozone on structure and transport properties for perovskite stannate La-doped BaSnO3 epitaxial films

Abstract

Here we investigate the influence of in situ ozone treatment on structure and carrier transport in La-doped BaSnO3 BLSO) films. It is found that introducing ozone during the film growth significantly inhibits the formation of oxygen vacancies and the occurrence of Sn2+ ions. The amount of oxygen vacancies decreases consistently with the increase of the ozone content, which further increases the in-plane lattice constant along with the relief of the in-plane compressive strain. More importantly, the reduction of oxygen vacancies gives rise to the augment of the threading dislocation density in the BLSO films, leading to the deterioration of carrier mobility. These findings demonstrate that the existence of Sn2+ ions does not apparently suppress the electron mobility in BLSO films, and the presence of oxygen vacancies is beneficial for reducing the density of threading dislocations, facilitating the mobility enhancement. All these findings would be beneficial for understanding the role of oxygen vacancy in carrier transport properties and for further optimizing the mobility of BLSO films.