Gas sensing properties of p-type semiconducting Cr-doped TiO2 thin films

• Published in: Sensors and actuators. B, Chemical Chemical, 2002-03, Vol.83 (1-3), p.160-163
• Main Authors: Li, Yongxiang, Wlodarski, Wojtek, Galatsis, Kosmas, Moslih, Sayed Hassib, Cole, Jared, Russo, Salvy, Rockelmann, Natasha
• Format: Article
• Language: English
• Subjects: Cr-doped TiO2; Gas sensing; p-type semiconductor; Sol–gel process
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/S0925-4005(01)01031-0

Cr2O3–TiO2 thin films were prepared from the sol–gel process. Titanium butoxide was used as the precursor material. The solution was mixed with a chromium compound then spun onto sapphire and silicon substrates at 2500rpm for 30s. The films were annealied at temperatures of between 400 and 700°C for 1h. The X-ray diffraction (XRD), scanning electronic microscope (SEM), Rutherford backscatter spectrometry (RBS) and X-ray photoelectron spectroscopy (XPS) techniques were employed for microstructural characterazations. The responses to both NO2 and O2 gases confirmed that the films are of a p-type behaviour at operating temperatures between 350 and 400°C. The films showed a good response to oxygen, in the range from 100ppm to 10% of O2 at an operating temperature of 370°C. The response is also fast and stable. The p-type Cr-doped TiO2 thin films have potential for development of a novel gas sensors.