Metalorganic chemical vapor deposition and investigation of nonstoichiometry of undoped BaSnO3 and La-doped BaSnO3 thin films

Wide bandgap (similar to 3 eV) perovskite transparent conductive oxide material exhibiting superior electric properties is highly desired in today's optoelectronics. Just recently La-doped barium stannate (LBSO) bulk n-type semiconductor with outstanding carrier mobility (similar to 320 cm(2) V-1 s(-1)) at high carrier density (1020 cm(-3)) has been discovered. Highly conductive thin LBSO film synthesis has been challenging due to large lattice mismatch and nonstoichiometry as being the least investigated. Therefore, in this work, the Pulsed injection metalorganic chemical vapor deposition method was used for the growth of undoped BaSnO3 (BSO) and La-doped BaSnO3 thin films. Film depositions were carried out on monocrystalline LaAlO3, SrTiO3, Al2O3 substrates in wide stoichiometric range. Deviation from stoichiometric composition in BSO (Sn/Ba) and LBSO (Sn/(Ba + La)) had a significant impact on microstructure, optical, and electric properties while maintaining cubic symmetry. Near-stoichiometric films even grown at a high rate of similar to 10 nm/min showed sufficient electric properties.