退火对ZnO:Al薄膜光致发光性能的影响

 采用溶胶-凝胶工艺在石英衬底上制备ZnO:Al（AZO）薄膜，通过不同温度的退火处理，研究了退火对AZO薄膜结构和光致发光特性的影响。XRD图谱表明：所制备的薄膜具有c轴高度择优取向，随着退火温度的升高，(002)峰的强度逐渐增强，同时(002)峰的半高宽逐渐减小,表明晶粒在不断增大。未退火样品的光致发光（PL）谱由361 nm附近的紫外带边发射峰和500 nm附近的深能级发射峰组成。样品经退火后，以500 nm为中心的绿带发射逐渐减弱，而带边发射强度有所增强,并且逐渐红移到366 nm附近，与吸收边移动的测试结果相吻合。对经过不同时间退火的样品分析表明，AZO薄膜的发光特性与退火时间也有很大关系，时间过短可见波段的发射较强，但时间过长会使晶粒发生团聚，导致紫外发射峰强度减弱。

Effect of annealing on photoluminescence of ZnO:Al thin films prepared by sol-gel method

Al doped ZnO thin films were fabricated on quartz substrates by sol-gel method.An X-ray diffraction(XRD) was used to analyse the structural properties of the thin films.All the thin films have a preferential c-axis orientation,which enhances in the annealing process.From the spectrometer transmittance data,the optical absorption of AZO films was found to have a redshift with an increase in annealing temperature.From the PL measurement the near band edge(NBE) emission and deep-level(DL) emission are observed in unannealed AZO thin films.However,after annealing at high temperature,the DL emissions of the thin films are depressed.As the annealing temperature increases,the peak of NBE emission has a shift to region of lower photon energy,which is coincident with the results from the transmittance data.Results also show that the PL spectrum depends not only on the processing temperature but also on the processing time.