Effect of Annealing Temperature on Structural, Morphological, Optical and Electrical Properties of Spray Deposited V2O5 Thin Films

Abstract

Nanostructured vanadium pentoxide (V2O5) thin films have been deposited by a simple and cost-effective spray pyrolysis technique (SPT) at substrate temperature 300 °C and post annealed at atmospheric conditions in the temperature range from 300 °C to 500 °C at a constant rate of heating. The influence of post annealing heat treatment on the crystallization of V2O5 has been investigated. Films were characterized structurally by X-ray diffraction, morphologically by Scanning electron microscopy, optically using UV-Vis spectrophotometer, electrical characterization using Hall probe and Raman spectroscopy has been carried out for phase confirmation. X-ray diffraction analysis (XRD) revealed that, as deposited films were orthorhombic structures with a preferential orientation along (0 0 1) direction. Moreover, it was observed that crystallite size increases from 22 nm to 56 nm with increase in annealing temperature. Optical properties of these samples were studied in the wavelength range 300-1000 nm. Raman spectrum confirms the layered structure of V2O5 thin films. Hall Effect measurements indicate that the change in carrier concentration with increase in annealing temperature.

Thermally Induced Phase Transition and Defect‐Assisted Nonlinear Absorption and Optical Limiting in Nanorod Morphology V2O5 Thin Films

“…Increased annealing temperature resulted in a decrease in transmittance of the thin films due to the coalescence of the nanorods. [ 60 ] Moreover, a slight increase in film thicknesses, as discussed earlier, could also be responsible for the decreased film transmittance.…”

Multichromic Vanadium Pentoxide Thin Films Through Ultrasonic Spray Deposition

“…38 Moreover, annealing temperature dependent increase in film thickness and grain size can also lead to a decrease in the transmittance of the films. [73][74][75] The optical band gap values of V 2 O 5 films were determined via UV-vis spectroscopy measurements using Tauc's relation,…”

Electrochromic Behavior of Vanadium Pentoxide Thin Films Prepared by a Sol–Gel Spin Coating Process

“…Similar trend was reported by Yelsani et al, where they have obtained the decrease in E g values from 2.40 to 2.14 eV, after postannealing treatment on V 2 O 5 films deposited by spray pyrolysis method. [ 38 ] In addition, Madhuri et al have observed the substrate temperature‐induced decrease in bandgap values (from 2.57 to 2.40 eV) of electron beam evaporated V 2 O 5 films. [ 18 ] The decrease in optical energy bandgap with increasing annealing temperature may be due to the higher average crystallite size and lower strain values.…”

“…Extrapolating the linear region of Tauc plot (Figure 4) to zero absorption coefficient gives the E g of the films. [38] In addition, Madhuri et al have observed the substrate temperature-induced decrease in bandgap values (from 2.57 to 2.40 eV) of electron beam evaporated V 2 O 5 films. [18] The decrease in optical energy bandgap with increasing annealing temperature may be due to the higher average crystallite size and lower strain values.…”

“…The Raman spectra clearly show that as annealing temperatures are increased, the obtained peaks become broader, which could be due to the structural reorganization of V 2 O 5 thin films. [38] At 450 C, the Raman peak is slightly decreasing, which may be due to the increase in grain size [39] or distortion occurred in V 2 O 5 crystal structure and also due to the oxygen vacancies observed in the prepared films. [40]…”