Effect of the Substrate Movement on the Optical Properties of ZnO Thin Films Deposited by Ultrasonic Spray Pyrolysis

[摘要] Using a modified ultrasonic spray pyrolysis (USP) system, ZnO thin films were deposited on the substrate moved back and forth (ZO1) and rotated (ZO3) as well as fixed (ZO2) in the conventional USP technique. Prepared thin films are pure ZnO with a preferred crystalline orientation of (0 0 2) in the hexagonal wurtzite structure. Diffraction angle shift implies a decrease lattice parameter alongc-axis anda-axis 0.2% and 0.3%, respectively. Maximum strain has been found for ZO1 which is about (−) 0.17%. These strain values show that presence of compressive strain due to moving substrates as depositing ZnO films. The film deposition process on the rotated quartz substrate isprovided to obtain the thinner film. The grain size and root-mean- square value of roughness increase with thickness. Strong UV emission was observed at~390 nm assigned to the band gap transition from photoluminescence measurements. Energy shifted about 39 meV for ZO3 sample with respect to that of ZO2 film deposited in conventional USP system. This behaviour is confirmed with (002) diffraction peak shifting. So, the compressed lattice will provide a wider band gap for these films.E2phonon frequency values have not given a considerable shifting.

[学科分类] 材料工程