Effect of temperature and film thickness on structural and mechanical properties of c-axis oriented Zn0.95Mg0.05O thin films

Zn0.95Mg0.05O solutions were synthesized by the sol-gel technique using Zn and Mg-based alkoxide. The structure, microstructure, and mechanical properties of the c-axis oriented Zn0.95Mg0.05O thin films were investigated as a function of film thickness and temperature. Zn0.95Mg0.05O thin films were grown on a glass substrate using the sol-gel dip-coating method. Then, the thin films were annealed at various temperature values (500-600 degrees C for 30 min) under air. X-ray diffraction of the Zn0.95Mg0.05O thin films results indicated that all samples had a ZnO wurtzite structure and (002) orientation. The photoluminescence (PL) measurements revealed the near-band emission (NBE), the Zn, related emission, and the excess oxygen interstitials and their complexes with zinc vacancies. The surface morphologies and microstructure of all samples were characterized by using Scanning Electron Microscope (SEM). It was observed that surface morphologies of Zn0.95Mg0.05O thin film were dense, uniform, crack free and without pinhole. Effects of film thickness and temperature on stress in Zn0.95Mg0.05O thin films were analyzed theoretically to see whether there was any crack inside of the thin films and substrate or not. It was found that the stress component values of thin films were compressive; however, for glass substrate they were tension.