title: Using Pt Dopant and Sol Gel Technology for Sensitivity Enhancement of TiO<inf>2</inf>/SnO<inf>2</inf>Humidity Sensors.
abstract: The sensitivity of the humidity sensor based on hybrid thin films of nanostructure TiO<inf>2</inf>/SnO<inf>2</inf>with Pt dopant was successfully increased. The humidity-sensitive materials, TiO<inf>2</inf>/SnO<inf>3</inf>, were prepared by sol gel technology. The microstructure of the sensing film after calcination was investigated by the Field Emission gun Scanning Electron Microscopy (FESEM) and revealed that the metal oxide hybrid had about 10 nm grain size. For studying the effect of Pt dopant on the humidity-sensitive responses, 1 ml to 10 ml of Pt standard solution was added into the colloidal solution. To compare the humidity sensor of Pt dopant with that of no Pt dopant, operational frequencies and electrode spacing were set under the relative humidity from 30 % to 95 % at the ambient temperature of 22 &#176;C. We demonstrated that adding Pt dopant remarkably enhanced the sensitivity of TiO<inf>2</inf>/SnO<inf>2</inf>humidity sensor, and further decreased the TiO2/SnO2 resistance, which was 3.3 times lower than that without Pt dopant at the high humidity.
authors.affiliation: Department of Engineering Science, National Cheng Kung University, 1 University Road, Tainan 701, Taiwan; Electronics Research & Service Organization, Industrial Technology Research Institute, Taiwan.
authors.forename: Wen-Yang
authors.initials: WY
authors.lastname: Chang
authors.forename: Wen-Wang
authors.initials: WW
authors.lastname: Ke
authors.forename: Yu-Sheng
authors.initials: YS
authors.lastname: Hsieh
authors.forename: Nai-Hao
authors.initials: NH
authors.lastname: Kuo
authors.forename: Yu-Cheng
authors.initials: YC
authors.lastname: Lin