Room temperature sensitivity of Ta doped nanocrystalline ZnO films to NH3 exposure

Undoped (ZnO) and doped with Ta (ZnO:Ta) films have been deposited by magnetron sputtering of a ZnO target and co-sputtering of the target with Ta chips on its surface respectively. The structural and optical properties of the films have been performed by X-ray Diffraction Spectroscopy (XRD), optical transmittance and reflectance measurements. The sensitivity of the undoped ZnO thin films and those doped with Ta (ZnO:Ta) to exposure to NH3 was measured by the ratio of the resistivity in air to that in the presence of the target gas. A higher sensitivity was observed in the Ta doped ZnO film.. It is shown that ZnO thin films doped with Ta have a potential application as room temperature sensors.