Photoresponse and H2 gas sensing properties of highly oriented Al and Al/Sb doped ZnO thin films

ZnO:Al and ZnO:Al/Sb thin films have been prepared and investigated. The thin films were deposited on Si substrates by the sol–gel method. The structural, optical and electrical properties of ZnO films have been investigated by spectrophotometry, ellipsometry, X-ray diffraction and current–voltage characterizations. It is found that the films exhibit wurtzite structure with a highly c-axis orientation perpendicular to the surface of the substrate, a high reflectivity in the infrared region and a response to illumination. Furthermore, it has been found that Si/(ZnO:Al/Sb)/Al photodiode is promising in photoconduction device while Si/(ZnO:Al)/Al can be used as gas sensor responding to the low H2 concentrations.