Influence of substrate temperature on structural and optical properties of ZnO thin films prepared by cost-effective chemical spray pyrolysis technique

•Cost effective spray pyrolysis unit is constructed.•Influence of substrate temperature on the structural, optical, morphological properties are studied.•Spray prepared ZnO thin films exhibits Rice-like grain morphology.

Over the past few decades semiconductor metal oxides have stimulated research interests owing to their important role in fundamental research and future applications in the field of energy conversion and sensors. So the present research work has been focused on the synthesis, growth mechanisms and physical properties of ZnO thin films prepared by cost-effective chemical spray pyrolysis technique. Desirable properties of thin films can be easily tailored by chemical spray pyrolysis technique by optimising the spray parameters. ZnO thin films were deposited on glass substrates with various substrate temperatures ranging from 573 K to 723 K. The influence of substrate temperature on structural, morphological and optical properties have been analyzed via XRD, SEM, UV–VIS–NIR spectroscopy, PL studies respectively. The Structural study reveals that all the spray deposited ZnO thin films have polycrystalline nature with preferential orientation along (100) plane. Optical studies show that the direct band gap values increases from 3.14 to 3.20 eV. PL studies shows that the intensity of emission peaks differ according to the substrate temperature. Smooth and uniform morphology obtained from SEM analysis. The optical transmittance observed in the visible region is more than 85% for all films other than 573 K as substrate temperature.