Wide bandgap semiconductor La-doped BaSnO3 (LBSO) has attracted increasing attention due to its outstanding electron mobility reaching 320 cm2V-1s-1 at room temperature [1]. Many researchers have developed LBSO epitaxial films. However, the obtainable carrier mobility is much lower in thin films compared to single crystals. Worse electrical performance has been attributed to the formation of the structural defects and nonstoichiometry. Thin film electrical properties (mainly carrier mobility) were demonstrated to depend on film morphology, structure and lattice mismatch between the substrate and the film. The composition-dependent properties to-date are not fully investigated. Therefore, in this work thin La-doped BaSnO3 films were deposited using pulsed injection metal organic chemical vapor deposition (PI-MOCVD) method on different substrates using different stoichiometric ratios of Sn/Ba. This method allowed easy compositional control of thin films and to investigate composition-dependent thin LBSO film properties.
Thin films were characterized using investigated using X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. La-doped film carrier mobility and carrier concentration were determined using Hall measurements. Surface morphology, microstructure and electrical properties of LBSO films were highly dependent on the selected substrate and film composition. Here we report thin film electron mobility, surface morphology and elemental core-shell electron spectroscopy dependence on thin film nonstoichiometry and successful optimization of the deposition process to achieve highly desirable electrical and structural properties.