@article{oai:kitami-it.repo.nii.ac.jp:00006901, author = {Washizu, E. and Yamamoto, A. and Abe, Y. and Kawamura, M. and Sasaki, K.}, issue = {1-4}, journal = {Solid State Ionics}, month = {Dec}, note = {The effects of deposition conditions, including substrate temperature and sputtering gas pressure, on the optical and electrochromic (EC) properties of WO_3 films prepared by RF reactive sputtering were investigated. The maximum optical band gap energy of 3.15 eV was obtained on a room-temperature substrate temperature, and decreased with increasing substrate temperature. However, the maximum refractive index of about 2.5 was obtained at a sputtering gas pressure of 5 mTorr and a substrate temperature of 500°C, and decreased with decreasing substrate temperature and with increasing pressure. The decrease in bandgap energy and refractive index are thought to have been caused by an increase in WO_3 cluster size and a decrease in film density, respectively. Electrochromic (EC) response times of the WO_3 films were measured in an electrolyte of 1N H_2SO_4 aqueous solution. Fast EC responses were obtained for the WO_3 films with wide band gap energies and low refractive indices. The results indicate that the optical properties of WO_3 films are useful indicators of EC response., application/pdf}, pages = {175--180}, title = {Optical and electrochromic properties of RF reactively sputtered WO_3 films}, volume = {165}, year = {2003} }