衬底温度对PLD法生长的Mg_(0·05)Zn_(0·95)O薄膜结构和发光特性的影响

Influence of substrate temperature on the structure and photoluminescence of Mg_(0.05)Zn_(0.95)O thin films grown by pulsed laser deposition

用脉冲激光沉积(PLD)法在不同温度的Si(111)衬底上成功制备了c轴择优取向的Mg0·05Zn0·95O薄膜.通过X射线衍射(XRD)和光致发光谱(PL)研究了衬底温度对Mg0·05Zn0·95O薄膜结构和发光特性的影响,探讨了薄膜的结晶质量与发光特性之间的关系.结果表明,在衬底温度为450℃时生长的Mg0·05Zn0·95O薄膜具有很好的c轴取向和较强的光致发光峰.室温下分别用激发波长为240,300和325nm的氙灯作为激发光源得到不同样品的PL谱,分析表明紫外发光峰和紫峰来源于自由激子的复合辐射且发光强度与薄膜的结晶质量密切相关,蓝绿发光峰与氧空位有关.此外,探讨了衬底温度影响紫外光致发光峰红移和蓝移的可能机理.

Highly c-axis oriented Mg0.05Zn0.95O thin films were fabricated on Si（111） substrates at different temperature by pulsed laser deposition. The influence of the substrate temperature on the structure and luminescent properties of Mg0.05Zn0.95O thin films were studied by XRD and photoluminescence （PL） spectra and the relationship between the crystalline quality and PL properties of thin films was discussed. The results indicate that the Mg0.05Zn0.95O thin films grown at substrate temperature of 450℃ show good c-axis orientation and strong PL peaks. Different PL spectra are acquired at room temperature using xenon lamps as excitation light sources,with excitation wavelengths of 240, 300 and 325 nm, respectively. The UV peaks and violet peaks were found to originate from free excition radiation recombination and the PL intensity was related to crystalline quality, and the blue-green peaks may be related to the oxygen vacancies. We also discuss the physical mechanism throngh which the substrate temperature affects the red shift and blue shift of UV PL peaks.