Growth and characterization of single crystal InAs nanowire arrays and their application to plasmonics

Abstract

The growth of single crystal InAs nanowire arrays on crystalline and amorphous substrates is described. This method is quite simple and fast, and uses only a bare InAs substrate as a source and a gold colloid on the growth substrate. High quality InAs nanowires can be produced by this technique, with the nanowire diameter controllable by the gold colloid size and the nanowire length controlled by the growth time and growth temperature. By a proper choice of substrate, parallel, non-interacting nanowire arrays can be formed, as well as arrays exhibiting a cross-over geometry.These geometries can have a significant impact on the plasmonic properties, specifically on surface enhanced Raman (SERS). Results indicate a significantly enhanced SERS signal for nanowire arrays which contain wire crossings, which is explained in terms of electric field "hot" spots.

Morphology and Microstructure of InAs Nanowires on GaAs Substrates Grown by Molecular Beam Epitaxy

“…The dominance of ⟨111⟩ orientation on different GaAs substrates is in accordance with previous literature about InAs NWs grown on InAs substrates. [5,10,12,21] Although Fortuna et al [22] mentioned that lattice mismatch between the substrate and NWs can play an important role in determining the tendency of NWs to grow along ⟨111⟩ direction, here we do not observe such effect caused by the large lattice mismatch (6.9%) between InAs NWs and GaAs substrates. In addition, we also find that some nanowires stick to each other, as can be seen from Fig.…”

“…1(a), we can clearly see the Au seed particle located on the top of the nanowire. Although the growth temperature adopted here is relatively low compared to the research work by other groups, some researchers [12,21] also prove that Au catalysts can still stay in a liquid state when the actual growth temperature is lower than the eutectic temperature shown in Au-In phase diagram. More in-depth investigations are needed before a complete picture can be drawn for NW growth processes.…”