Quantum Confinement, Surface Roughness, and the Conduction Band Structure of Ultrathin Silicon Membranes

被引：37

作者：

Chen, Feng ^{[1
,2
]}

Ramayya, Edwin B. ^{[1
]}

Euaruksakul, Chanan ^{[1
]}

Himpsel, Franz J. ^{[1
]}

Celler, George K. ^{[3
]}

Ding, Bingjun ^{[2
]}

Knezevic, Irena ^{[1
]}

Lagally, Max G. ^{[1
]}

机构：

[1] Univ Wisconsin, Madison, WI 53706 USA

[2] Xi An Jiao Tong Univ, Xian 710049, Peoples R China

[3] Soitec USA, Peabody, MA 01960 USA

来源：

ACS NANO | 2010年 / 4卷 / 04期

关键词：

silicon nanomembrane; quantum confinement; surface roughness; thermoelectric; valley splitting; THERMOELECTRIC FIGURE; SI NANOCRYSTALS; MOBILITY; PERFORMANCE; SPECTROSCOPY; SCATTERING; TRANSPORT; STRAIN;

D O I：

10.1021/nn100275z

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

We report direct measurements of changes in the conduction-band structure of ultrathin silicon nanomembranes with quantum confinement. Confinement lifts the 6-fold-degeneracy of the bulk-silicon conduction-band minimum (CBM), Delta, and two inequivalent sub-band ladders, Delta(2) and Delta(4), form. We show that even very small surface roughness smears the nominally steplike features in the density of states (DOS) due to these sub-bands. We obtain the energy splitting between Delta(2) and Delta(4) and their shift with respect to the bulk value directly from the 2p(3/2)->Delta transition in X-ray absorption. The measured dependence of the sub-band splitting and the shift of their weighted average on degree of confinement is in excellent agreement with theory, for both Si(001) and Si(110).

引用

页码：2466 / 2474

页数：9

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