Figure 1. (a) Bird's eye view scanning electron micrograph of a GaN nanowire ensemble prepared on an epitaxial multilayer graphene (MLG) film synthesized on SiC. (b) High-resolution cross-sectional transmission electron micrograph revealing the presence of a continuous multilayer graphene film between the GaN nanowires and the SiC substrate.
In this work, we demonstrate an all-epitaxial and scalable growth approach to fabricate single-crystalline GaN nanowires on graphene by plasma-assisted molecular beam epitaxy. As substrate, we explore several types of epitaxial graphene layer structures synthesized on SiC. The different structures differ mainly in their total number of graphene layers. Because graphene is found to be etched under active N exposure, the direct growth of GaN nanowires on graphene is only achieved on multilayer graphene films. The analysis of the nanowire ensembles prepared on multilayer graphene by Raman spectroscopy and transmission electron microscopy reveals the presence of graphene underneath as well as in between nanowires, as desired for the use of this material as contact layer in nanowire-based devices. The nanowires nucleate preferentially at step edges, are vertical, well aligned, epitaxial, and of comparable structural quality as similar structures fabricated on conventional substrates.
1 | Author | S. Fernández-Garrido , M. Ramsteiner , G. Gao , L. A. Galves , Bharat Sharma , P. Corfdir , G. Calabrese , Z. de Souza Schiaber , C. Pfüller , A. Trampert , J. M. J. Lopes , O. Brandt , L. Geelhaar |
Title |
Molecular Beam Epitaxy of GaN Nanowires on Epitaxial Graphene |
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Source | Nano Lett. , 17 , 5213 ( 2017 ) | |
DOI : 10.1021/acs.nanolett.7b01196 | Cite : Bibtex RIS |