1D nanostructures grown on GaAs and InP substrates

Abstract

Nowadays nanoelectronics is a very promising and dramatically developing field for physics basic research and R&D activities. The most common material for nanoelectronic components are the semiconductor nanowires, carbon nanotubes and metal nanowhiskers. There are still many questions about the growth and synthesis of these 1D nanostructures and the true nature of the growth mechanisms is yet undiscovered. There are some growth theories but neither of them can describe the whole growth process without leaving unanswered questions. Nanowires can easily be grown on III-V semiconductor substrates. The key is the presence of some catalyst particles. According to one of the growth theories the particles (atoms, molecules) diffuse into the catalyst particle which is a gold seed with the approximate diameter of 100nm in our experiments. A crystallization phenomenon occurs after reaching the critical concentration in the gold seed. Consequently a cylinder-shaped nanowire will grow under the gold particle (Tip-type growth). We show a 3D FEM (Finite Element Method) time-dependent model of the gas-gold-substrate system from which we can determine the concentration of dissolved matter in the gold particle vs. time. This model is an extended version of previous solid-state diffusion (SSD) models. The FEM modelling was performed based on earlier results of TEM (Transmission Electron Microscopy), SEM (Scanning Electron Microscopy) experiments and EDS (Energy-Dispersive Spectroscopy) analysis.