Structure, optical and electronic structure studies of Ti:ZnO thin films

Abstract

Ti doped ZnO (TZO) thin films are stabilized by means of sputtering on quartz substrates and their structural, optical and electronic structure studies are carried out. The effect of different substrate temperature during growth and post deposition annealing effect is emphasized in TZO films. Structural characterization reveals that the TZO films have a wurzite phase with (0001) preferred orientation and lattice strain tends to relax at higher growth temperature and lower growth rate. Crystallite size, lattice strain and the band gap demonstrate dependency on deposition parameters. Moreover, these are strongly influenced by post deposition annealing treatment. The changes induced in the electronic structure of TZO films due to varying deposition parameters and post annealing treatment are understood through X-ray absorption spectroscopy and X-ray absorption near-edge structure measurements. The secondary ion mass spectrometry predicts that concentration of Ti in TZO film is laterally homogeneous but is vertically modulated upon post annealing while the Zn and O have followed stable concentration profile.