纳米氧化锌的水热法生长及其光学特性研究

利用水热法成功制备了纤锌矿结构的ZnO纳米小刺球结构．小刺球结构是由多片ZnO纳米晶在生长过程中自组装而成．随着反应溶液中S_2-的含量的增加，小刺球结构的尺寸逐渐变小．这是由S_2-在ZnO样品中引入的缺陷增多造成的，表明大量的缺陷会对形成小刺球结构的片状ZnO的有序生长机制造成影响．缺陷的增多对带边发光一直起到削弱的效果；但在一定程度上会增强ZnO可见光的发光强度，但更多的缺陷会导致非辐射复合中心的大量增加，在荧光光谱中表现为可见光发光强度随着反应溶液中S_2-的含量的增加而先变强再变弱．合理调整反应溶液中S_2-的浓度可以生长出合适紫外、可见光强度比的ZnO材料，这在半导体白光发光器件中具有潜在的应用价值．

THE HYDROTHERMAL SYNTHESIS AND OPTICAL CHARACTERIZATION OF ZnO NANOSTRUCTURES

This paper synthesized the nano- size thorn - ball structure of wurtzite ZnO by using hydrothermal method. The thorn - ball structure is composed of self - assembled ZnO multi - sheets during the sample growth process. With the increase of S_2- concentration in reaction solutions, the size of thorn - ball structure ZnO is reduced, which is caused by the increase of defects in samples. This result shows that large quantity of defects can affect the growth mechanism of ordered thorn - ball ZnO. The increase of defects must weaken the near band edge emissions. But for the visible range emissions, the increase of defects can enhance the visible luminescence. The nonradiative recombination rate will be increased with the more increase of defects. By changing the concentration of S_2- in reaction solution, the ZnO nanostructures with suitable intensity ratio of visible emission can be obtained, which has a potential application in white light emitting devices.