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

Abstract

Cr2O3-TiO2 thin films have been prepared by 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 2500 rpm for 30 s. The films were annealled at temperatures of between 400 and 700°C for 1hr. The X-Ray Diffraction (XRD), Scanning Electronic Microscope (SEM), Rutherford Backscatter Spectrometry (RBS) and X-ray Photoelectron Spectroscopy (XPS) techniques were employed for microstructural characterizations. The response to both NO2 and O2 gas confirmed that the films are of a p-type behaviour between 350 and 400°C. The films showed a good response to oxygen, in the range from 1..