摘要： Amorphous tungsten oxide film under different oxygen flow rates were deposited by direct current sputtering. The deposition process was monitored by the Langmuir probe and optical emission spectrometer. From the voltage change at target and all plasma parameters, the deposited films under low oxygen flow rate (5 sccm) are metal-rich tungsten oxides. The films were completely oxidized under higher oxygen flow rate (10–20 sccm). The color of films is also changed from dark blue to transparent accordingly. We analyzed the deposited films by XRD, SEM, EDS and XPS confirmed that the compositions change of deposited films. More interestingly, the XPS reveals the existence of inter-valance state W5+ in all sample films besides the commonly recognized W6+ and W4+ states. This may be accredited to the incomplete bonding between tungsten and oxygen due to the amorphous structures of films. The color change of deposited films examined by the UV–Vis–NIR spectroscopy indicates that the optical band gap is widened and absorbance reduced for films deposited under high oxygen flow rate. These results together indicate that WO3 films with compositions between metal-rich and full oxide are easier for chemical insertion of electrons and ions to achieve better electrochromic functions. •Amorphous WO3 films are deposited by DC sputtering under different O2 flow rates.•The deposition is monitored by the Langmuir probe, optical emission spectrometer.•Low oxygen flow rate (5 sccm) creates dark blue metal-rich tungsten oxides films.•Oxygen flow rate at 10–20 sccm assures the deposition of amorphous WO3 films.•The metal-rich films are suitable for cation insertion to be electrochromic. 出版者： Elsevier Ltd 出版日期： 2015-08-01 出處： Vacuum, 2015-08, Vol.118, p.125-132 版權： 2015 Elsevier Ltd 識別號： ISSN: 0042-207X 識別號： EISSN: 1879-2715 識別號： DOI: 10.1016/j.vacuum.2015.01.020
