玻璃中CdSeS纳米晶体的室温光致发光谱  

Photoluminescence of CdSeS Nanocrystals at Room Temperature

作　　者：王引书[1] 郑东[2] 孙萍[1] 王一红[1] 刘惠民[1] 桑丽华[1] 王若桢[1] 

机构地区：[1]北京师范大学物理系,北京100875 [2]北京师范大学测试中心,北京100875

出　　处：《发光学报》2003年第2期139-143,共5页Chinese Journal of Luminescence

基　　金：国家自然科学基金(29890217);北京师范大学青年基金资助项目

摘　　要：对掺有过饱和的镉、硒和少量硫的玻璃在500～800℃分别退火4h,生长了不同尺寸的CdSe1-xSx纳米晶体。测量了纳米晶体的室温吸收光谱和光致发光(PL)光谱,550℃生长的样品在300～800nm的范围没有观察到吸收和发光峰,表明温度低于550℃玻璃中不能形成纳米晶体。生长温度在600～650℃,纳米晶体的PL光谱主要为两个宽的发光带,即带边激子发光带和通过表面态复合的发光带。随着生长温度的升高,带边复合发光的蓝移减小,通过表面态的发光逐渐消失,并出现了叠加于宽发光带上的一系列明显的弱发射峰。不同温度生长的样品中,叠加峰的能量相同。同一样品中叠加峰的能量不随激发光波长的变化而变化。CdSe1-xSx nanocrystals were grown by annealing silica glass wit h supersaturate Cd,Se and S at 500～800℃ for 4h, respectively. The absorption and p hotolumines cence (PL) of the nanocrystals excited with light of different wavelength were m easu red at room temperature. The PL spectra were discussed. In the sample annealed a t 550℃, no absorption and emission were observed in the range of 300～ 800nm. This suggested that no CdSe1-xSx nanocrystals formed. The a bsorption of 1S3/21Se shifted toward to red with the rising of growth temperatures from 600～800℃ due to the weakening of quantum confinement with the increase of nanocrystal sizes. Ma inly broadened peaks named H and L bands, H band corresponding to rec ombination at the band edge and L band corresponds to radiative recombination as sociated with deep traps, were observed in the grown at 600～650℃ . As the growth temperature was raised higher, L bands disappeared gr adually and only H bands were observed. This indicated that deep trap density de creased with the increase of growth temperature and the deep traps mainly were s urface states. H bands shifted red with the increase of nanocrystal growth tempe ratures. This was due to quantum size effects because nanocrystal mean size incr eased with the increase of growth temperature. In the nanocrystals grown at 650 ～ 800℃, a series of obvious small peaks superposed on the broadened bands were al so observed. The peak energy for nanocrystals grown at different temperatures wa s similar and only new peaks were observed in samples grown at lower temperature s. The superposed peaks could be divided into two groups. Within each group, the peaks distributed periodically with energy separation of 120meV. There was 50me V energy separation between the two groups. The energy separation was much hig her than that of LO phonon. Sizeselective PL spectra of nanocrystals collected using excitation wavelength between 488～650nm in

关 键 词：纳米晶体 PL光谱 精细结构 CdSeS 玻璃 室温 光致发光谱 镉硒硫三元化合物 

分 类 号：O471.4[理学—半导体物理] TB383[理学—物理]