Optical and structural properties of Sr-doped ZnO thin films

ZnO thin film is a widely studied optoelectronic material at present. Doping is an important method to adjust its structural, optical, electrical and magnetic properties. A lot of doped ZnO thin films especially those doped with Al, Ga, Co have been extensively investigated. However, the Sr-doped ZnO thin films are still few reported up to now. In this work, the Sr-doped ZnO thin films have been deposited by sol-gel method. Their structural and optical properties have been analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible spectrophotometry and photoluminescence (PL), respectively. The results show that the appropriate Sr-doping levels can improve the crystalline quality and ultraviolet emission performance of ZnO thin films and suppress their visible emissions. This probably results from the decrease of point defects such as oxygen vacancy etc. due to the Sr-doping. What is more, it is also found that there exists a saturation value of Sr-doping concentration in ZnO thin films deposited using our prepared sol system, which is because the dopant Strontium chloride is slightly soluble in ethanol. (C) 2014 Elsevier B.V. All rights reserved.