Core-Shell Germanium/Germanium–Tin Nanowires Exhibiting Room-Temperature Direct- and Indirect-Gap Photoluminescence

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• 作者：Andrew C. Meng ; Colleen S. Fenrich ; Michael R. Braun ; James P. McVittie ; Ann F. Marshall ; James S. Harris ; Paul C. McIntyre
• 刊名：Nano Letters
• 出版年：2016
• 出版时间：December 14, 2016
• 年：2016
• 卷：16
• 期：12
• 页码：7521-7529
• 全文大小：719K
• ISSN：1530-6992

文摘

Germanium–tin alloy nanowires hold promise as silicon-compatible optoelectronic elements with the potential to achieve a direct band gap transition required for efficient light emission. In contrast to Ge_1–xSn_x epitaxial thin films, free-standing nanowires deposited on misfitting germanium or silicon substrates can avoid compressive, elastic strains that inhibit formation of a direct gap. We demonstrate strong room temperature photoluminescence, consistent with band edge emission from both Ge core nanowires, elastically strained in tension, and the almost unstrained Ge_1–xSn_x shells grown around them. Low-temperature chemical vapor deposition of these core-shell structures was achieved using standard precursors, resulting in Sn incorporation that significantly exceeds the bulk solubility limit in germanium.