Oscillatory Band Gap Behavior in Small Diameter Si-Clathrate Nanowires

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• 作者：Inna Ponomareva ; Ernst Richter ; Antonis N. Andriotis ; Madhu Menon
• 刊名：Nano Letters
• 出版年：2007
• 出版时间：November 2007
• 年：2007
• 卷：7
• 期：11
• 页码：3424 - 3428
• 全文大小：409K
• 年卷期：v.7,no.11(November 2007)
• ISSN：1530-6992

文摘

Electronic structure analysis of small cagelike silicon nanowires is carried out and reveals many surprising features. The band gap values forall the nanowires are found to be smaller than their bulk counterparts. The most intriguing aspect appears to be the alternating sequence ofdirect and indirect band gaps as the diameter changes. This is attributed to the type of surface geometry. We illustrate this with two well-known clathrate forms as well as a new hexagonal clathrate structure with a direct band gap in the optical region.