Demonstration of Hexagonal Phase Silicon Carbide Nanowire Arrays with Vertical Alignment

SiC nanowire based electronics hold promise for data collection in harsh environments wherein conventional semiconductor platforms would fail. However, the full adaptation of SiC nanowires as a material platform necessitates strict control of nanowire crystal structure and orientation for reliable performance. Toward such efforts, we report the growth of hexagonal phase SiC nanowire arrays grown with vertical alignment on commercially available single crystalline SiC substrates. The nanowire hexagonality, confirmed with Raman spectroscopy and atomic resolution microscopy, displays a polytypic distribution of predominantly 2H and 4H. Employing a theoretical growth model, the polytypic distribution of hexagonal phase nanowires is accurately predicted in the regime of high supersaturation. Additionally, the reduction of disorder-induced phonon density of states is achieved while maintaining nanowire morphology through a postgrowth anneal. The results of this work expand the repertoire of SiC nanowires by implementing a low-temperature method that promotes polytypes outside the well-studied cubic phase and introduces uniform, vertical alignment on industry standard SiC substrates.