| AVS 58th Annual International Symposium and Exhibition | |
| Surface Science Division | Tuesday Sessions |
| Session SS-TuP |
| Session: | Surface Science Poster Session |
| Presenter: | Hiromu Suzuki, Kogakuin University, Japan |
| Authors: | H. Suzuki, Kogakuin University, Japan H. Shukur, Kogakuin University, Japan S. Ibrahim, Kogakuin University, Japan I. Takano, Kogakuin University, Japan |
| Correspondent: | Click to Email |
WO3 is known as the material with an n-type semiconductor characteristic showing electrochromism (EC). The amorphous WO3 thin film especially is used for a display device or a high-speed reaction sensor using electrochromism. WO3 thin films for electrochromism have been fabricated by various film formation methods such as reactive sputtering and vacuum evaporation. The relationship between Ar gas and O2 gas introduced during the film formation is the important condition for the structure of WO3 thin film. The structure decides the electrochromic characteristic of the WO3 thin film. In the reactive sputtering method Ar/O2 gas flow rate especially induces the structure change of WO3 thin film and the surface morphology.
In this study, WO3 thin films were deposited by reactive magnetron sputtering with a W target in the condition of changing an Ar/O2 gas flow rate. In the condition the WO3 thin films with various crystal structures were fabricated. The relationship between the crystal structure and the electrochromic property were investigated with the great interest.
The WO3 thin films were deposited by the multi process system with the helicon sputtering source on an Indium-tin oxide (ITO) coated glass and stainless steel (304SS) used as a substrate. The formation conditions of the WO 3 thin film were changed from 5 to 10 sccm in Ar gas flow rate and from 10 to 20 sccm in O2 gas flow rate under a constant DC source power. The substrate temperature was kept at 473 K using an infrared lamp. The crystal s tructure and electrochromic property were investigated by X-ray diffraction (XRD) and UV-VIS spectrometer respectively. The crystal structure turned from the WO3 thin film with the peak (112) to the WO3 thin film with the peak (002), (112) and (022) with increasing Ar gas flow rate, while increase of O2 gas flow rate gradually turned up the main peak (112). The maximum efficiency of electrochromic property was obtained at 7.5 sccm in Ar gas flow rate and 15 sccm in O2 gas flow rate.