硅量子点的形状及其弯曲表面效应  

Shape and curved surface effect on silicon quantum dots

作　　者：黄伟其[1] 周年杰[1] 尹君[1] 苗信建[1] 黄忠梅[1] 陈汉琼[1] 苏琴[1] 刘世荣[2] 秦朝建[2] 

机构地区：[1]贵州大学纳米光子物理研究所,光电子技术与应用省重点实验室,贵阳550025 [2]中国科学院地球化学研究所,矿床地球化学国家重点实验室,贵阳550003

出　　处：《物理学报》2013年第8期174-179,共6页Acta Physica Sinica

基　　金：国家自然科学基金批准号资助的课题~~

摘　　要：硅量子点的弯曲表面引起系统的对称性破缺,致使某些表面键合在能带的带隙中形成局域电子态.计算结果表明:硅量子点的表面曲率不同形成的表面键合结合能和电子态分布明显不同.例如,Si—O—Si桥键在曲率较大的表面键合能够在带隙中形成局域能级,而在硅量子点曲率较小的近平台表面上键合不会形成任何局域态,但此时的键合结合能较低.用弯曲表面效应(CS)可以解释较小硅量子点的光致荧光光谱的红移现象.CS效应揭示了纳米物理中又一奇妙的特性.实验证实,CS效应在带隙中形成的局域能级可以激活硅量子点发光.Curviform surface breaks the symmetrical shape of silicon quantum dots on which some bonds can produce localized electronic states in band gap. The calculation results show that the bonding energy and electronic states of silicon quantum dots are different on various curved surfaces, for example, an Si-O-Si bridge bond on curved surface provides the localized levels in band gap and its bonding energy is shallower than that on facet. The red-shifting of PL spectrum on smaller silicon quantum dots can be explained by curved surface effect. Experiments demonstrate that silicon quantum dots are activated for emission due to the localized levels formed in the band gap.

关 键 词：硅量子点 弯曲表面效应 表面键合 局域能级 

分 类 号：O471.1[理学—半导体物理]