衬底温度对ZnMgO薄膜结构和光致发光性能的影响

Effect of Substrate Temperature on Structure and Photoluminescence of ZnMgO Films

利用超声喷雾热解方法以不同的沉积温度(450～550℃)在石英衬底上制备出一系列ZnMgO薄膜。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和光致发光谱(PL)表征了样品的晶体结构、表面形貌和光学性能。结果表明衬底温度对薄膜结构性能和光学特性影响显著。所有薄膜都呈六角纤锌矿多晶结构,其中在530℃条件下制备的样品C轴择优最明显,晶粒尺寸均匀,表面形貌平整,结晶质量最好。薄膜的光致发光谱显示随着温度的升高深能级跃迁范围逐渐减小,近紫外带边发光峰逐步出现。衬底温度为530℃时在374.5nm处出现了明显的近紫外发光峰,且几乎没有明显的深能级跃迁出现。

ZnMgO films were deposited on quartz glass substrates by the ultrasonic spray pyrolysis at different substrate temperatures（450～550℃）.The structural,surface morphological and optical properties of the samples were investigated by X-ray diffraction（XRD）,scanning electron microscope（SEM）and photoluminescence（PL）spectroscopy.The results demonstrate that the substrate temperature has important effect on structural and optical characteristics.All the films have hexagonal wurtzite polycrystalline structures and the c-axis preferential orientation has an optimum temperature of 530℃.The sample prepared at this temperature owns uniform grain size,smooth surface morphology and better crystalline quality.The width of deep-level emission decreases and the near band edge（NBE）ultraviolet emission peak appears with the increase in temperature by the PL spectrum.When the temperature arrives to 530℃,a distinct NBE emission peak can be observed at 374.5nm,while the deeplevel emission is almost undetectable.