使用水热法在石英衬底上制备了掺铝氧化锌(AZO)薄膜,采用X射线衍射仪、扫描电子显微镜和低温光致发光谱技术对薄膜的微结构和发光性能进行了表征。结果表明,薄膜由氧化锌纳米锥构成,纳米锥直径大部分都在100 nm以下,且具有明显的沿c轴择优生长的特征。此种方法制备的AZO薄膜在室温下存在两个较宽的发光峰,即紫外-紫光发光峰和绿光-红光发光峰。铝掺杂强烈地影响两个发光峰的相对强度。随着掺杂量的增大,(1)紫外-紫光发光峰的相对强度和绝对强度都迅速增大,并在铝掺杂量达到10%时达到最大值,(2)绿光-红光发光峰中,各子发光峰的相对强度也发生一定变化,主要表现为长波子发光峰的发光强度的相对增大。铝掺杂还导致薄膜的发光谱中出现一个极少见的位于355 nm处的发光峰,该发光峰随铝掺杂量的增大而增强。薄膜的低温光致发光谱表明,随着薄膜温度由10 K升高到267 K,薄膜的紫外-紫光发光峰变化不明显,但绿光-红光发光峰的强度则随着温度的增加而快速单调减小,呈现荧光热猝灭现象。由发光中心的多声子发射造成的非辐射激子复合应该是造成这种热猝灭的主要原因。
The Al-doped ZnO( AZO) films were synthesized in hydrothermal method on quartz substrates. The films,grown under the optimized conditions,were characterized with X-ray diffraction,scanning electron microscopy,and photoluminescence( PL) spectroscopy. Two wide peaks of the PL spectrum were observed,one is the ultraviolet( UV)-violet peak,the other is the green-red peaks. The results show that the Al-doping and temperature strongly affect the PL spectra of the films,consisting of the hexagonal,c-axis preferentially orientated,ZnO nano-rod with conical ending. For example,the intensity of UV and violet peaks rose up with an increase of the Al-content,maximizing at Al 10. 0%( wt). As the temperature increased from 10 to 267 K,the UV and violet peaks remained almost unchanged,but the green-red emission peaks quenched. Possible mechanisms responsible for the quenching were tentatively discussed.