| Abstract [eng] |
Lanthanum-doped barium stannate (La:BaSnO3 or LBSO) is a promising transparent conductive oxide (TCO) material that has the potential to reduce the reliance on tin-doped indium oxide (ITO). This study focused on depositing thin LBSO films on strontium titanate (STO), lanthanum aluminate (LAO), and magnesium oxide (MgO) substrates using pulsed-injected metalorganic chemical vapor deposition (PI-MOCVD). The objective was to investigate the effect of oxygen partial pressure during deposition on the morphology and electrical properties, such as charge mobility and concentration, of LBSO. The elemental composition, surface morphology, optical properties, and electrical properties of the LBSO thin films were analyzed based on different oxygen partial pressures. The results revealed that the deposited LBSO thin films on the SafC substrate exhibited high transparency, transmitting up to 83% of visible light spectra. X-ray diffraction (XRD) analysis confirmed the formation of a predominantly pure LBSO phase, with a few low-intensity peaks potentially indicating lattice distortion. Increasing the barium content in the lattice structure led to the formation of various crystal orientations that were not textured to the substrate. Oxygen partial pressure had no significant influence on LBSO phase formation. XRD and scanning electron microscopy (SEM) images showed that increasing the tin content resulted in more textured LBSO films, with visible absence of non-textured crystallites. Decreasing the oxygen partial pressure resulted in the coalescence of crystallites, forming a uniform layer that promotes efficient carrier mobility. The electrical measurements in van der Pauw configuration demonstrated that decreasing the oxygen partial pressure generally improved the carrier mobility, reaching 106 cm2V-1s-1 for LBSO||STO(100) films. The carrier concentration tended to increase with decreasing oxygen partial pressure due to the formation of oxygen vacancies, which, when ionized, contributed to the free carrier concentration. In conclusion, the stoichiometry and oxygen partial pressure during the deposition process significantly influence the electrical properties of LBSO. The findings highlight the importance of controlling these factors for optimizing the performance of LBSO thin films in various applications. |
