Effect of solution molarity on the characteristics of vanadium pentoxide thin film

摘要

Vanadium pentoxide (V2O5) thin films have been prepared by spray pyrolysis technique. The influence of solution molarity on the characteristics of the V2O5 has been investigated. X-ray diffraction analysis (XRD) showed that, the films deposited at >= 0.1 M were orthorhombic structure with a preferential orientation along < 0 0 1 > direction. Moreover, the crystallinity was improved by increasing solution molarity. The microstructure parameters have been evaluated by using a single order Voigt profile method. The optical band gaps, determined by using Tauc plot, have been found to be 2.50 +/- 0.02 and 2.33 +/- 0.02 eV for the direct and indirect allowed transition, respectively. Also the complex optical constants for the wavelength range 300-2500 nm are reported. At room temperature, the dark conductivity as a function of solution molarity showed the range of 5.74 x 10(-2) +/- 0.03 to 3.36 x 10(-1) +/- 0.02 Omega(-1) cm(-1). While at high temperature, the behaviour of electrical conductivity dominated by grain boundaries. The values of activation energy and potential barrier height were 0.156 +/- 0.011 and 0.263 +/- 0.012 eV, respectively. (c) 2005 Elsevier B.V. All rights reserved.