氧化锌纳米晶体的光谱分析

采用沉淀法并通过控制前驱体的煅烧温度来制备粒径不同的氧化锌(ZnO)纳米晶体，对粒子的透射电镜照片进行分析，结果表明，制备出的纳米粒子分散性好、形貌一致、粒径分布集中。样品的X射线衍射光谱分析表明，随着前驱体煅烧温度增加，晶体粒径增大、结晶度提高;样品的紫外-可见吸收光谱的峰位随粒径减小而发生蓝移，这一实验结果表明ZnO纳米晶体呈现出较明显的量子限域效应;红外吸收光谱测量结果表明，用沉淀法制备的ZnO纳米晶体的表面会吸附一小部分残余的离子，对红外吸收光谱中的ZnO特征振动峰随粒径减小发生宽化和红移的现象进行了理论分析;光致发光光谱测量结果表明，ZnO纳米晶体在紫外区(360 nm)存在一较弱的发光峰，而在可见区(468 nm)存在一较强的发光峰，与理论计算结果进行比较后，认为锌空位点缺陷是导致ZnO纳米晶体可见区发光的主要原因。

Spectral Analysis of ZnO Nanocrystals

ZnO nanocrystals with different size were prepared with deposition method at different annealing temperatures.The images of transmission electron microscopy show that the nanocrystals have a good dispersion characteristic,uniform shape, and centralized distribution.The X-ray diffraction spectra of samples show that the size and the crystallization of the nanocrystals increase as the annealing temperature grows.The peak positions of ultraviolet and visible spectra exhibit a blueshift as the crystal size decreases,which demonstrates the quantum confinement effect of ZnO nanocrystals.The infrared spectra present that there are a few residual ions adhering to the surface of ZnO nanocrystals.In addition,it was observed in the infrared spectra that the peaks at about 430 cm~(-1) shift to the red and become broader with the decrease in particle size.Two emission bands were clearly observed from the photoluminescence spectra of the samples.One is a relatively narrow emission band in the ultraviolet region(360 nm),while the other is a broad emission band in the visible region(468 nm).Compared with the theoretical calculation it is suggested that the latter originates from the zinc vacancies.