Studies on Structural, Optical and Electrical Properties of ZnO Thin Films Prepared by the Spray Pyrolysis Method

Zinc oxide transparent thin films have been deposited on glass substrates by a pneumatic spray pyrolysis technique. Surface investigations such as AFM, SEM and XRD patterns of the films were investigated for as-deposited and annealed in air atmosphere. The morphology of the films is strongly related to the annealing temperature. By XRD, the amorphous phase is identified for as-deposited films and it changes to polycrystalline with the (1 0 0) and (1 0 1) as preferential crystallographic orientation for annealed samples. The as-deposited films exhibited highest optical transmittance and the direct band gap energy was found to vary from 3.23 to 3.07 eV with annealing temperatures. The electrical parameters of the samples were obtained by applying the dc four-probe technique. The effects of annealing environment on the luminescence characteristics of ZnO thin films were investigated by PL films are described here.