Nanorods and nanocones for advanced sensor applications

Abstract

Zinc-doped gallium phosphide (GaP) nanowires and nanocones were grown by metal organic vapour phase epitaxy (MOVPE) on GaP〈1 1 1〉B substrates by a VLS technique using 30 nm colloidal gold particles as seeds. The growth was performed in an AIX 200 MOVPE low-pressure reactor between 500 and 690 °C. As the growth temperature Tg was increased, GaP nanocrystals changed their shape from rod-like nanowires at 500 °C through tapered nanocones at between 610 and 660 °C and finally to biconical shape at 690 °C. The nanocones had hexagonal cross-sections at their bases following the orientation of the substrate. GaP substrates were nanostructured with nanowires or nanocones with the aim to create experimental platforms for further exploration namely for (1) the deposition of Ag nanoballs that should facilitate surface enhanced Raman scattering, and (2) the synthesis of a thin molybdenum disulphide (MoS2) layer that would be suitable for solar cell and water disinfection applications.