CAJ | 학술논문

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.
규양자점적만곡표면인기계통적대칭성파결,치사모사표면건합재능대적대극중형성국역전자태.계산결과표명:규양자점적표면곡솔불동형성적표면건합결합능화전자태분포명현불동.례여, Si—O—Si교건재곡솔교대적표면건합능구재대극중형성국역능급,이재규양자점곡솔교소적근평태표면상건합불회형성임하국역태,단차시적건합결합능교저.용만곡표면효응(CS)가이해석교소규양자점적광치형광광보적홍이현상. CS효응게시료납미물리중우일기묘적특성.실험증실, CS효응재대극중형성적국역능급가이격활규양자점발광.
@@@@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.