退火对电弧离子镀制备的ZnO薄膜的影响

Influence of Annealing on ZnO Thin Films Prepared by Cathodic Vacuum Arc Deposition

采用阴极电弧离子镀在Si、Al2O3以及玻璃衬底上制备出具有择优取向的ZnO薄膜,并对其进行退火处理。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、光致发光光谱(PL)、紫外-可见光光谱仪对ZnO薄膜的结构、表面形貌和光学性能进行分析。XRD结果表明,所制备的ZnO薄膜具有很好的ZnO(002)择优取向,退火使ZnO(002)衍射峰向高角度方向偏移。SEM结果表明,随着退火温度升高,表面晶粒由隆起的山脉或塔状变为平面状,晶粒002面呈六边状。PL谱结果表明,随着退火温度的升高,紫外发光峰强度逐渐增强,可见光发光峰强度逐渐相对减弱。紫外可见光透过谱结果表明,退火使可见光透过率增高,光学带隙发生红移。

By using cathodic vacuum arc deposition, uniform and compacted ZnO thin films with preferred orientation were successfully deposited on the silicon, Al2O3 and glass substrates. Thus the ZnO thin films were annealed in air to optimize the property. The structures, morphologies, and the optical properties of ZnO thin films were investigated by X-ray diffraction （XRD）, scan electron microscopy （SEM）, UV-visible spectrophotometer and photoluminescence （PL） at room temperature. The XRD patterns show that all ZnO thin films annealed in air have preferred orientation of ZnO （002）, and the diffraction peaks shift to the higher angle with the upward annealing temperatures. SEM images show that grain-morphologies change from tower or mountain shape to plane shape with six-side with raising temperature. Both PL and transparency spectra indicate that impurities were reduced by annealing, and the transparency of ZnO thin films annealed at 550℃ increase to 85% in visible range, and the corresponding optical band gaps decreasing.