Characterization of electrochromic WO₃ thin films fabricated by an RF sputtering method

WO₃ thin films were fabricated by RF sputtering deposition. The as-deposited thin films showed uniformity and good adhesion to an ITO layer. The deposition rate increased as the applied power was increased during the RF sputtering deposition. While the as-deposited WO₃ thin films deposited in argon gas alone had very low stoichiometry showing a degradation phenomenon during the transmittance measurement, the WO₃ thin film deposited in a mixture of argon and oxygen gases exhibited better cyclability and afaster response time. The WO₃ thin film prepared at 800 W in the gas mixture showed the best performance with a coloration efficiency of 30.2 cm².C^-1 and a coloring response time of 7 s.