采用阴极还原方法,在透明导电玻璃(ITO)上制备了高c轴择优取向的ZnO薄膜.通过X射线衍射、扫描电子显微镜等表征技术,研究了沉积电流对ZnO薄膜的结构、应力状态及表面形貌的影响;利用光致荧光光谱及透射光谱等分析方法,探讨了沉积电流变化对ZnO薄膜的光学性能的影响.研究结果显示:各沉积电流下均可制得高c轴取向的ZnO薄膜;薄膜表面形貌受电流的影响较大;从透射谱可以看出,薄膜在可见光波段有较高透射率,且薄膜厚度随沉积电流的增大而增大.光致荧光测量表明,电化学沉积的ZnO薄膜具有明显的带隙展宽.而且,随着沉积电流的增加,带隙发光强度逐渐减弱,缺陷发光逐渐增强.
ZnO thin films were electrodeposited on glasses coated with a transparent-conductive film (InSnO) with different deposition currents. We have studied the dependence of microstructure, morphology and photoluminescence (PL) on the deposition current by X-ray diffraction, scanning electron microscopy and PL measurement at room temperature. We found that all the films show highly c-axis textured structure and the surface morphology is strongly current-dependent. The transmission spectra show that the films have a transmittance higher than 80% in the visible range. The films have an increase in thickness withthe deposition current. The PL spectra exhibit two emission bands, an ultraviolet (UV) one from the exciton transition and a visible light one that might emerge from the defects in the films. The UV emission band has an obvious blueshift, which is found to be due to in doping during the deposition. With the increase of deposition current, the UV emission decreases while the visible light emission goes up.