Growth of Mo-doped ZnO (MZO) Films by Chemical Spray Process

The present study report on the growth of Mo-doped ZnO (MZO) films by chemical spray process and the results on film characterization. Using the spray pyrolysis method, molybdenum (Mo)-doped zinc oxide (ZnO) thin films were produced on corning 7059 glass substrates. The layers were deposited with the Mo-doping constant set at 2 at. % for a range of solution concentrations from 0.01M to 0.2M. The change in properties of the films by varying Zn molarity was studied. X-ray diffraction studies showed polycrystalline nature of the films with (002) preferred orientation and exhibited wurtzite structure. The layers formed at 0.1M molar concentration exhibited better crystallinity compared to other layers. Raman studies are in good agreement with XRD. Surface morphology varied significantly with Zn-molar concentration. An average transmittance of the layers was 80% in the visible region and the band gap varied from 3.31 eV to 3.5 eV. The detailed analysis of the results including photoluminescence are reported and discussed. The optical results identified that films with 0.1M concentration showed optical transmittance of 80% in the visible region and the energy band gap varied between 3.31eV to 3.5eV. The photoluminescence data supported the change in band gap with solution concentration. These crystalline, single phase and transmissive Mo-doped ZnO layers could be used as window layers in solar cells.