Crystal Phase Induced Bandgap Modifications in AlAs Nanowires Probed by Resonant Raman Spectroscopy

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• 作者：Stefan Funk ; Ang Li ; Daniele Ercolani ; Mauro Gemmi ; Lucia Sorba ; Ilaria Zardo
• 刊名：ACS Nano
• 出版年：2013
• 出版时间：February 26, 2013
• 年：2013
• 卷：7
• 期：2
• 页码：1400-1407
• 全文大小：461K
• 年卷期：v.7,no.2(February 26, 2013)
• ISSN：1936-086X

文摘

We report on a major modification of the fundamental electronic band structure of AlAs when grown as a nanoscaled wurtzite crystal. Resonant Raman spectra of individual AlAs鈥揋aAs core鈥搒hell nanowires display a resonance between 1.83 and 2.18 eV for the AlAs E₁(TO) phonon mode. Our findings substantiate the lowest conduction band of wurtzite AlAs to comprise 螕₈ symmetry and a low effective mass in agreement with calculations reported recently. The electronic resonance falls below the X, L, and 螕 valleys known for AlAs in the zincblende phase. This result points toward a direct nature of wurtzite AlAs and is expected to apply more generally to semiconductors that in the bulk phase exhibit L valleys at lower energies than the conduction band at the 螕 point.

Keywords:

AlAs nanowires; wurtzite; electronic band structure; resonant Raman spectroscopy