作　　者： ; ; ; ;

机构地区： 华南理工大学材料科学与工程学院

出　　处： 《光谱学与光谱分析》 2009年第11期2881-2884,共4页

摘　　要： 研究了不同粒径ZnO纳米颗粒样品(17～300nm)的时间光谱,通过对各粒径样品时间积分光谱的谱带结构进行高斯拟合解迭,发现光子能量位于ZnO谱带低能侧的高斯拟合成份Xc3的荧光中心波长随粒径的减小而红移,同时发光带的寿命也随之缩短。基于ZnO谱带低能侧的高斯拟合峰发光带强烈依赖于ZnO样品粒径的谱带特性,提出了与ZnO禁带内的表面态能级有关,同时研究表明,表面态在尺寸降到一定程度的纳米体系中起着重要的作用。 The size-dependence of photoluminescence （PL） of ZnO nanoparticles with diameter from 17 to 300 nm was demonstrated by time resolved laser spectroscopy. Broad PL spectra were obtained and found to consist of three Gaussian components. The authors found that the PL peak position and relative amplitude depend on the size of nanoparticles for the Gaussian PL band inside the energy band-gap. The Gaussian band Xc3 is believed to be associated with the transitions between surface states. It is well known that as the dimensions of a semiconductor are reduced to the nanometer scale,one of the key features is the large surface-to-volume ratio. The larger surface-to-volume ratio in nanostructures means the larger bulk density of dangling bonds. The existence of dangling bond in a crystal surface is likely to change a state localized by splitting the state out of the border of the energy gap. The Gaussian peak Xc3 lying inside the band gap of ZnO indicates the existence of such initial states in the forbidden bulk band gap. Furthermore,we found that with the decrease in particle size,the Gaussian curve Xc3 shifts to the lower energy. With the particle size increaseing,the comparative amplitude of PL band Xc3 descends rapidly and so does the corresponding relative PL intensity. The sensitive correlation between the particle size and the optical properties of the below gap broadband shows a key role of the surface states recombination in PL of nanosized particles. Furthermore,our exploration indicates that the surface states recombination plays a dominant role in PL of nanostructures with particle sizes down to a certain degree.

关 键 词： 纳米颗粒 时间分辨 表面态发射

领　　域： [理学] [理学]