纳米ZnO薄膜的热蒸发法制备及其光电特性研究

Fabrication and Photoelectrical Properties of ZnO Thin Films Prepared by Thermal Evaporation Process

以醋酸锌为原料、O/Ar的混合气体为携载气体,在500℃的温度下应用热蒸发法在p型Si基片上生长纳米ZnO薄膜,并研究了其形貌、结构和光电特性。X-射线(XRD)衍射结果显示所制备ZnO纳米晶体呈六角纤锌矿结构;扫描电子显微镜(SEM)观察发现生长的ZnO薄膜平整均匀,纳米晶体颗粒平均尺寸为25nm。应用紫外-可见光吸收谱分析了其吸收特性,发现该ZnO薄膜在紫外波段具有很强的吸收,其吸收边位于320nm处。由于量子限制效应,与体材料相比,该吸收边存在明显的蓝移。应用光致发光谱(PL)研究了其发光特性,发现该ZnO薄膜在近紫外以及蓝-绿光波段具有强烈的受激发射。最后,还研究了ZnO薄膜的电容-电压(C-V)特性。

ZnO nanocrystals thin films were prepared on Si substrate by thermal evaporation process at 500oC temperature,using zinc acetate dihydrate as the source materials and O/Ar mixture as the carrying gas.The morphology,structure,and the photoelectrical properties of the as grown ZnO thin film are studied.The results of X-ray Diffraction（XRD）shows that ZnO nanocrystals are characterized by the wurtzite structure.Observations by a Scanning Electron Microscopy（SEM）show that the ZnO nanocrystals thin film is flat and uniform,and the nanoparticles are of an average size of 25nm.In the absorption spectrum the ZnO films take a strong violet absorption with an absorption edge of 320nm,which takes a blue shift compared with the bulk ZnO.Correspondingly,it gives a remarkable UV emission and a blue-green emission in the Photoluminescence（PL）spectra.The capacitance-voltage（C-V）properties of the films are investigated.