Au-catalyst-free epitaxy of InAs nanowires

Semiconducting nanowires have been intensively studied in order to exploit unique optical and electrical properties that develop at the nano-scale. Commonly, nanowires are produced using Au nanoparticles (∼50 nm diameter) as seed particles on the surface applied prior to epitaxy. The Au particle acts as a preferred nucleation site for nanowire growth. This report demonstrates InAs nanowire epitaxy on GaAs(1 0 0) and GaAs(1 1 1) substrates without the use of Au nanoparticles. InAs nanowires are formed by using in-situ generated metallic droplets via decomposition of the metalorganic source during OMVPE. The InAs nanowires grow preferentially in the [1 1 1] direction, although evidence of [1 0 0] growth is observed. InAs nanowires in excess of 0.5 μm in length have been observed on GaAs(1 0 0) substrates. The effect of OMVPE conditions such as substrate orientation, V/III ratio, and growth temperature on the InAs nanowire structure is described.