Sprayed vanadium pentoxide thin films: Influence of substrate temperature and role of HNO3 on the structural, optical, morphological and electrical properties

• DOI: 10.1016/j.apsusc.2017.02.039
• Publication Date: 2017-02-09T09:03:11Z
• Authors: Mudaliar Mahesh M...; S. Mathuri; K. Ramamurthi; R. Ramesh Babu; K. Sethuraman
• Keywords: Pentoxide; Vanadate; Field emission microscopy

Abstract Spray pyrolysis technique was employed to deposit vanadium pentoxide thin films at different substrate temperature of 300 °C, 325 °C, 350 °C, 375 °C and 400 °C from nitric acid added ammonium meta vanadate aqua precursor solution. X-ray diffraction analysis of the deposited films showed the formation of orthorhombic vanadium pentoxide phase with growth along (101) plane. Average crystallite size showed variation from 21 to 42 nm as a function of substrate temperature. The film deposited at 400 °C acquired average visible transmittance of ∼77% in the 500–800 nm range. Direct optical band gap of the vanadium pentoxide thin film was slightly increased from 1.98 to 2.05 eV. Field emission scanning electron microscope and atomic force microscope studies showed that the size and shape of the flakes formed on the surface of the film deposited from the nitric acid added ammonium meta vanadate precursor solution were effectively modified with increase in substrate temperature. The carrier concentration and conductivity of the film deposited at 375 °C respectively is 2.138 × 10 13 cm −3 and 1.0 × 10 −5 Ω −1 cm −1 which are relatively high when compared to other films. Photoluminescence spectra of the vanadium pentoxide films deposited at 375 °C and 400 °C showed intense emission peaks at 475 nm and 552 nm.