衬底温度对ZnO薄膜结构和光学特性的影响

采用射频磁控溅射的方法在不同温度下Si(111)衬底上制备出了具有高c轴择优取向的ZnO薄膜,利用X射线衍射(XRD),原子力显微镜(AFM),光致发光(PL)谱等分析手段研究了衬底温度对ZnO薄膜微观结构及发光特性的影响.通过XRD和AFM分析发现随着衬底温度的升高,制备样品的X射线衍射半高宽(FWHM)减小,晶粒尺寸增大,在300 ℃时晶粒尺寸达到最大,但随温度的进一步升高(至400 ℃)晶粒尺寸减小,缺陷增多.薄膜样品PL谱均在520nm处出现绿光发射峰,本文认为这是由于氧空位(V_O)和氧替位(O_(Zn))共同作用的结果,绿光发射峰强度与其结晶质量密切相关,结晶质量越好,杂质和缺陷态就越少,发光峰越弱.

Influence of Substrate Temperature on Structure and Optical Properties of ZnO Thin Films

ZnO thin films with a strong c-axis orientation have been successfully deposited on Si(111) substrate at different temperatures by using magnetron sputtering system.The effect of substrate temperature on structure and optical properties of the ZnO thin films were investigated by means of XRD,AFM and PL.Through the analysis of the XRD and AFM,we found that as the substrate temperature changed from the room temperature to 300 ℃, the full width at half maximum(FWHM) of the diffraction peaks become narrower which indicated that the grain size increased .The sample grown at 300 ℃ has the largest grain size.But with the temperature further increasing,the grain size decreased .The PL results showed that a green photoluminescence peak at 520 nm appeared in all samples,we think the green emission is mainly attributed to oxygen vacancy defects(V_O) and antisite defects(O_(zn)),and it is found that the peak intensity of the PL is strongly related to the crystal quality,with the improvement of the crystal quality, the intensity of the green peak become weaker.