Control over the Number Density and Diameter of GaAs Nanowires on Si(111) Mediated by Droplet Epitaxy

Nano Letters (Impact Factor: 13.59). 07/2013; 13(8). DOI: 10.1021/nl401404w
Source: PubMed


We present a novel approach for the growth of GaAs nanowires (NWs) with controllable number density and diameter, which consists of the combination between droplet epitaxy (DE) and self-assisted NW growth. In our method, GaAs islands are initially formed on Si(111) by DE and subsequently, GaAs NWs are selectively grown on their top facet, which acts as nucleation site. By DE we can successfully tailor number density and diameter of the template of initial GaAs islands and the same degree of control is transferred to the final GaAs NWs. We show how, by a suitable choice of V/III flux ratio, a single NW can be accommodated on top of each GaAs base island. By transmission electron microscopy, as well as cathodo- and photo-luminescence spectroscopy we confirmed the high structural and optical quality of GaAs NWs grown by our method. We believe that this combined approach can be more generally applied to the fabrication of different homo- or hetero-epitaxial NWs, nucleated on the top of predefined islands obtained by DE.

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    • "Quantum dots have then been demonstrated around the nanoholes [5]. Also, metallic droplets have been successfully utilized in the fabrications of various quantum- and nanostructures such as quantum rings [6-9], quantum dots [10-12], and nanowires (NWs) [13] through ‘droplet epitaxy’ following the successful fabrication of homo-epitaxial GaAs nanocrystals on a GaAs substrate [14]. In addition, Au droplets have been adapted as catalysts for the fabrication of diverse NWs via various epitaxial approaches and have attracted extensive interest due to their unique properties such as surface plasmonic resonance, biosensing, quantum size effect, and biology [15-18]. "
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