热退火对ZnO-SiO_2复合薄膜的微结构及荧光特性的影响

Influence of Annealing Heat on the Microstucture and Fluorescent Characteristic of ZnO-SiO_2 Composite Film

采用脉冲激光沉积技术(PLD)在单晶Si衬底上制备了ZnO-SiO2复合薄膜。分别用SEM、XRD观察了样品在沉积态(300℃)及700℃和900℃下热退火后的形貌和结构。发现经700℃热处理后,样品中有第三相β-Zn2SiO4形成,经900℃热处理后的样品中硅锌矿型Zn2SiO4取代了β-Zn2SiO4成为第三相。研究了热退火处理前后样品的荧光特性变化,结果表明经700℃热处理后,荧光光谱与沉积态相比,紫外区域的发光强度有较大提高,可见光区域的宽带强度变弱;经900℃热处理后,紫外区域荧光强度与700℃处理相比略有减小,可见光发光带消失。

ZnO-SiO2 composite films were grown by pulsed laser deposition. Structures of the thin films were characterized by scanning electron microscope （SEM） and X-ray diffraction （XRD）. The results show that β-Zn2SiO4 particles can be detected in the film annealed at 700℃ and will be substituted by Zn2SiO4 at 900℃. From the PL results, UV intensity of the sample annealed at 700℃ increases highly comparing with that of unannealed, while it decreases slightly at higher annealing temperature （900℃） ; the luminescence of visible area decreases greatly after annealed at 700℃ comparing with that of unanealed, and disappears at 900℃.