Investigation of structural, optical and photoluminescence properties of nanostructured BaxSn1-xO2 thin films: An effect of Ba doping

Abstract

In this work, alkaline Ba doped SnO2, BaxSn1-xO2 (0.00 ≤ x ≤ 0.05), thin films have been synthesized by a cost-effective nebulizer spray pyrolysis method. X-ray diffraction analysis reveals that undoped and Ba doped SnO2 films are polycrystalline with tetragonal rutile structure. Field emission scanning electron microscopy analysis shows a morphological transformation of the crystallite grains from pyramidal-shaped to cubic-shaped. 3% Ba doped SnO2 sample exhibits excellence properties such as minimum resistivity (3.10 × 10−3 Ω cm), high mobility (21.47 cm2 V−1s−1) and maximum visible transmittance (86% at 550 nm). The optical band gap is estimated to be 4.04, 3.92, 3.89 and 4.10 eV for the samples prepared with Ba contents of 0, 1, 3 and 5%. In the photoluminescence investigation, a dominant blue emission band at ~ 474 nm is observed in the SnO2, whereas Ba doped SnO2 samples exhibit a strong violet emission band at ~ 430 nm. These emission bands can be attributed to the presence of defect-related states inside the band gap of SnO2.