Synthesis and structural, electrochromic characterization of pulsed laser deposited vanadium oxide thin films

Abstract

Vanadium oxide thin films with different stoichiometry have been deposited on In2O3:SnO2 (ITO) glass and Si wafer by pulsed laser deposition technique at different substrate heating or annealing temperatures and oxygen pressure. The structural properties of as-deposited and annealed VOx thin films were analyzed by using a scanning accessory of transmission electron microscope, x-ray diffraction, Fourier transform infrared spectrum, and Raman spectrum. The as-deposited thin film on the Si(111) wafer showed lower orientation with polycrystalline structure but those annealed at 300 °C above showed highly c-axis oriented growth. Highly c-axis oriented growth nanocrystalline V2O5 thin films with orthorhombic polycrystalline structure were successfully synthesized on ITO glass by using the scanning laser ablation technique at deposition temperature as low as 200 °C. Cyclic voltammograms at sweep rate of 50 mV/s shows that the no-long-term degradation was noticed at least up to 1000 cycles, and durability was verified to 8000 cycles in the voltage range between −1.2 and 1.4 V. It is demonstrated that these c-axis oriented V2O5 thin films on ITO are good candidates for cathode thin films for rechargeable batteries and electrochromic devices.