Investigation of the optical and structural properties of WO3thin films with different sputtering power supplies

Abstract

The purpose of this research was to investigate the optical and structural properties of tungsten oxide (WO 3 ) thin films deposited with three different sputtering power supplies: direct current (DC), DC pulse and radio frequency (RF). These WO 3 thin films were deposited on ITO glass and silicon substrate with different gas ratios of oxygen and argon (O 2 /Ar ratio). WO 3 thin film is the role of the electrochromic window was resulted from the advantages of large variation in optical density, high response efficiency, no toxicity and low cost. The experimental results showed that optical intensity increased with the increasing of O 2 /Ar ratio and all films have the 950cm -1 peak which the bonding of W +6 =O in Raman spectra. Hence, the O 2 /Ar ratio was changed from 0.4 to 0.8 to study the ability of coloring and bleaching for the three different power supplies. Anyways, the WO 3 thin films had the best electrochromic property at the O 2 /Ar ratio of 0.7, 0.6 and 0.6 for DC, DC pulse, and RF, respectively. The transmittances could be over 75% for all films at as-deposited and the deposition rates were between 0.8 and 0.1 As -1 . Simultaneously, the transmittance variations (ΔT) were 51%, 57% and 53% for DC, DC pulse, and RF power sources at wavelength of 550 nm, respectively. The coloration ability of WO 3 thin film deposition with power supply of DC pulse was better than that of the DC and RF.