Metal-Insulator Transition and Weak Localization in Oxygen Vacancy Doped BaSnO$_{\mathrm{\mathbf{3-\delta }}} Thin Films

We present detailed temperature-dependent electronic transport in oxygen vacancy doped BaSnO$_{\mathrm{3}}$ films grown on MgO(001), LaAlO$_{\mathrm{3}}$(001), and GdScO$_{\mathrm{3}}$(110) using high pressure oxygen sputter deposition. Various modes of high-resolution X-ray diffraction and scanning transmission electron microscopy confirm phase-pure, close to stoichiometric, smooth, epitaxial BaSnO$_{\mathrm{3}}$(001). [1] As-grown films are insulating, but can be made conductive with $n$-type carriers \textit{via }vacuum annealing, resulting in 300 K Hall mobilities up to 35 cm$^{\mathrm{2}}$V$^{\mathrm{-1}}$s$^{\mathrm{-1\thinspace }}$at 5\texttimes 10$^{\mathrm{19}}$ carriers per cm$^{\mathrm{3}}$. [1] Film thickness, reduction temperature, and substrate ($i.e$. lattice mismatch) have been systematically varied, enabling study of the insulator-metal transition, and, in particular, 2D weak localization at low temperatures. The results provide significant insight into the active transport mechanisms in BaSnO$_{\mathrm{3}}$ films. [1] Ganguly \textit{et al}. APL Materials 3, 062509 (2015).