Gas sensing properties of SnO2 thin films grown by MBE

A comparative study of the gas sensing properties between mono- and poly-crystalline tin dioxide thin films has been carried out. SnO2 films of thickness range 30-100nm were deposited on r-axis sapphire substrate in temperature range 260-550°C using the molecular beam epitaxy (MBE) technique. The crystalline structure of the resulting films was examined by using in situ high energy electron diffraction (RHEED), X-ray diffraction (XRD) and atomic force microscopy (AFM). The electrical properties of the films were characterized by using a Hall effect measurement system. Sensitivity towards different gases was tested and a comparison between mono- and poly-crystalline films is presented. Monocrystalline films were found to exhibit greater potential for continuous gas detection.