Vertically Oriented Growth of GaN Nanorods on Si Using Graphene as an Atomically Thin Buffer Layer

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• 作者：Martin Heilmann ; A. Mazid Munshi ; George Sarau ; Manuela Göbelt ; Christian Tessarek ; Vidar T. Fauske ; Antonius T. J. van Helvoort ; Jianfeng Yang ; Michael Latzel ; Björn Hoffmann ; Gavin Conibeer ; Helge Weman ; Silke Christiansen
• 刊名：Nano Letters
• 出版年：2016
• 出版时间：June 8, 2016
• 年：2016
• 卷：16
• 期：6
• 页码：3524-3532
• 全文大小：703K
• 年卷期：0
• ISSN：1530-6992

文摘

The monolithic integration of wurtzite GaN on Si via metal–organic vapor phase epitaxy is strongly hampered by lattice and thermal mismatch as well as meltback etching. This study presents single-layer graphene as an atomically thin buffer layer for c-axis-oriented growth of vertically aligned GaN nanorods mediated by nanometer-sized AlGaN nucleation islands. Nanostructures of similar morphology are demonstrated on graphene-covered Si(111) as well as Si(100). High crystal and optical quality of the nanorods are evidenced through scanning transmission electron microscopy, micro-Raman, and cathodoluminescence measurements supported by finite-difference time-domain simulations. Current–voltage characteristics revealed high vertical conduction of the as-grown GaN nanorods through the Si substrates. These findings are substantial to advance the integration of GaN-based devices on any substrates of choice that sustains the GaN growth temperatures, thereby permitting novel designs of GaN-based heterojunction device concepts.