Position controlled nanowire growth through Au nanoparticles synthesized by galvanic reaction

Semiconductor nanowires have emerged as promising materials for fundamental studies in quantum-confined systems and applications in nanophotonics and electronics, but major challenges remain in controlling nanowire properties, including their position and size. Here, we report a simple and efficient electrochemical process that combines galvanic reaction and electron-beam lithography to selectively synthesize gold nanoparticles that are consequently used for the growth of ordered GaAs nanowire arrays with pre-defined diameter and position. Size and density control of gold nanoparticles is achieved on non-patterned GaAs substrates by changing the reaction time and concentration of Au(3+) ions during the galvanic reaction. Spontaneous formation of localized etch pits is observed when the galvanic reaction is constrained to lithography-defined substrate regions, which confines small-diameter Au nanoparticles during the high temperature growth of GaAs nanowire arrays and enables epitaxial growth of well-ordered nanowire structures.