ZnO纳米线自组装可控生长的研究

【作者】 程和；

【导师】 李燕； 邓宏；

【作者基本信息】 电子科技大学 ， 材料学， 2006， 硕士

【摘要】 本实验采用催化辅助化学气相沉积技术制备了ZnO纳米线阵列体系,研究了工艺条件对ZnO纳米线阵列的生长的影响,并讨论了ZnO纳米线阵列的生长机理。探讨了ZnO纳米线阵列的紫外敏感特性及光谱响应。运用X射线衍射谱(XRD)、电子扫描显微镜(SEM)、原子力显微镜(AFM)、光响应测试系统等测试手段对样品的结构和光电性能进行了表征。结果表明:ZnO源控制在1350℃能够达到最理想的分解速度;通过控制催化剂的大小和分布状况实现了ZnO纳米线的直径和生长区域的控制;调节不同的生长温度得到不同尺度、形貌的纳米线,最终综合考虑催化剂,传输气体的流量,蒸发源的温度,背景真空等因素实现了对ZnO纳米线的可控生长。实验证明ZnO纳米线的生长是基于VLS生长机理,但和传统的VLS生长机理有所不同。在使用Au作为催化剂时,遵循VLS生长机理的顶部生长模式。使用Ag作为催化剂时,一般催化剂出现在纳米线的底部,我们认为是因为Ag和Si形成了Ag-Si合金的缘故。据此我们提出了在使用两种不同催化剂时ZnO纳米线生长的模型。ZnO纳米线光电特性研究表明:a-b取向的ZnO纳米线阵列具有很强的紫外光敏感特性,而且光响应速度很快(小于50ms)。最后本文探讨了氧气氛对ZnO纳米线阵列的光响应速度的影响,结果表明:光电流随着氧压的下降而增大,电流恢复变慢。更多还原

【Abstract】 ZnO nanowires have been grown on metal coated substrates by Chemical Vapor deposition and catalytic technology and studied the factors which effect the growth of ZnO nanowires. The growth mechanism of ZnO nanowires was also discussed. This paper reports the UV sensitive characteristic and spectral responsibility of ZnO nanowires.The structure, morphology and photoelectric properties of ZnO nanowires have been studied by X-ray diffraction (XRD), scanning electron microscope (SEM) and atom force microscope (AFM). We found that ZnO powder can be optimally decomposed in 1350℃. The diameter and growth area of ZnO nanowires strongly depended the size and distribution of catalyst. We can get different dimension in the different growth temperature. Then the ZnO nanowires arrays with the optimum properties were obtained by improving the process conditions. Experiment proved the growth of ZnO nanowires is based VLS mechanism, but have some different with traditional VLS mechanism. While using Ag as the catalyst, the catalyst appers in the bottom of the nanowires, we think it is because Ag and Si have formed Ag-Si alloy. We have proposed the growth model of ZnO nanowires wile using two kinds of catalyst.The photoelectric characteristic research of ZnO nanowires shows that a-b orientation ZnO nanowires arrays has very strong UV sensitive characteristic, and it is very fast response (smaller than 50mS). Finally, we discussion the impact on response speed of light of ZnO nanowires in the different oxygen atmosphere, the result shows that the photocurrent increases with decline that oxygen presses, but electric current resumes become slow.更多还原