Effect of source material on the transparent conducting properties of sprayed ZnO:Al thin films for solar cell applications

Two sets of aluminum doped zinc oxide films were deposited onto glass substrates using spray pyrolysis technique from starting solutions having two different host precursors zinc chloride and zinc acetate separately. The optical transparency in the visible range is better for films prepared from zinc acetate whereas electrical resistivity is better for their zinc chloride counterparts. But a third set of films prepared from the starting solutions having both the precursors in equal proportions, is found to possess good optical as well as electrical properties. The figure of merit of the latter is better (3.48 x 10(-3) (Omega/square)(-1)) than that of their single precursor counterparts (0.41 x 10(-3) and 0.32 x 10(-3) (Omega/square)(-1)). The x-ray diffraction studies showed that the preferential orientation is along the (002) plane for all the three sets, eventhough the degree of crystallinity is different in each case. Similarly three sets of undoped ZnO thin films were also fabricated in order to compare their properties with that their Al-doped ZnO counterparts. (C) 2013 Elsevier Ltd. All rights reserved.