Structural and Photoluminescence Properties of ZnO Thin Films Deposited by Ultrasonic Spray Pyrolysis

Abstract

The ZnO thin films on Si (111) substrate have been grown using ultrasonic spray pyrolisis (USP) at 450oC with different Zn concentration. The XRD patterns that the ZnO thin films have polycrystalline hexagonal wurtzite structure. The (002) and (101) peaks intensity change by different Zn molarities. Furthemore, according to the Scherer’s equation and Stokes-Wilson equation the crystallite size and internal strain of ZnO thin films in (002) and (101) peaks change with Zn concentration. Optically, PL spectra indicates that the ratio UV/GB emission of ZnO thin films is highest at Zn concentration 0.02 mol/ml. It’s predicted that by increasing Zn concentration, nonradiative transitions become dominant which originated from the defects such as lattice and surface defect. As conclusions the ZnO thin films with Zn concentration 0.02 mol/ml has better crystalline and optical quality.