Influence of Molecular Beam Epitaxy (MBE) Parameters on Catalyst-Free Growth of InAs Nanowires on Silicon (111) Substrate

The effect of molecular beam epitaxy parameters on catalyst-free growth of InAs nanowires using oxide templates on Si (111) substrate has been studied. Two different approaches, i.e., thermal and plasma-enhanced chemical vapor deposition, were used to prepare the oxide templates. The length, diameter, density, and quality of the nanowires depended strongly on the substrate temperature, As/In beam equivalent pressure ratio, and growth rate, whereas the type, thickness, and uniformity of the oxide were found to affect only the density of the nanowires. Nanowires could be grown effectively in only a very narrow range of these growth parameters. The surface morphological, structural, and optical properties of the nanowires were assessed using various techniques including field-emission scanning electron microscopy, high-resolution x-ray diffraction analysis, transmission electron microscopy, and Raman spectroscopy.