Effect of indium doping on microstructural, optical and fluorescence properties of ZnO thin films

The Undoped and 1-5 at.% In doped ZnO thin films were deposited on glass substrates by chemical spray pyrolysis technique. The samples were subjected to investigation for variation of their structural, morphological, optical transmittance and fluorescence properties with Indium doping concentration. The most intense three characteristic diffraction peaks , and for zincite phase reveals the formation of polycrystalline nanoparticulate ZnO thin films. The increase of peak intensity with Indium doping shows a tendency towards c-axis orientation of the ZnO crystallites. The crystal reorientation may be attributed to the oxygen deficiency in ZnO lattice. This also leads to decrease in crystallite size as well as nanoparticle size. The photoemission peaks at 450 nm and 480 nm has been attributed to intrinsic defect states like Oi, Zni and VZn, whereas the peak at 467 nm has been linked to defects caused by lattice deformations upon In doping.