Effect of solution concentration on the structural, optical and conductive properties of ZnO thin films prepared by sol–gel method
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ZnO thin films with different solution concentrations (0.1–0.9 mol/L) were prepared by a simple sol–gel dip-coating technique. X-ray diffraction, ultraviolet–visible spectroscopy, Hall effect measurements and photoluminescence (PL) spectroscopy were employed to investigate the effect of solution concentration on the structural,optical and electrical conductive properties of the ZnO thin films. The results showed that the ZnO thin films preferentially oriented along the (002) direction at higher solution concentration. The careful study of the optical and electrical conductive properties showed that the resistivity decreased monotonously, while the transmittance increased first and then decreased when solution concentrations changed from 0.1 to 0.9 mol/L. Photoluminescence spectra indicated that the defect-related blue emission was increased with the enhancement of solution concentration. The mechanism of the blue emission, and the reasons why high solution concentration was favorable for forming high c-axis oriented ZnO thin films and obtaining low resistivity were also discussed in detail.
KeywordsSolution Concentration Hall Mobility Blue Emission High Solution Concentration Electrical Conductive Property
This work is financially supported by National Natural Science Foundation of China (Grant No. 51172186), Specialized Research Fund for the Doctoral Program of Higher Education (Grant No. 20106102120051), NPU Foundation for Fundamental Research (NPU-FFR-JC201017, JC20100236).