Gas sensing performance of Al doped ZnO thin film for H2S detection

In the present work, Al doped ZnO films have been deposited by using simple chemical Spray Pyrolysis Technique. The films were deposited at temperature 400 degrees C. The structural, optical, surface and electrical properties have been investigated after and before incorporation of Al. The crystalline structure of the samples was analyzed by X-ray diffraction technique (XRD). All the XRD patterns of the films showed a well-defined polycrystalline phase, fitting well with the wurtzite phase of ZnO crystal structure. The preferential growth is found to be along (002) plane i.e. c-axis. The optical properties of the ZnO and AlZnO films were studied using UVeVisible absorption spectroscopy. Increase in band gap is observed with the increase in doping concentration of Al. The flake like morphology for undoped and Al doped ZnO thin films were analyzed from scanning electron microscopy (SEM). The sensor response was estimated by the change in the electrical resistance of the film in the presence and absence of H2S gas. The sensor response is found to be increased with the increase in doping concentration of Al. The sensor response in relation to operating temperature and the gas concentration has been systematically studied. (C) 2018 Elsevier B.V. All rights reserved.