Gallium loading of gold seed for high yield of patterned GaAs nanowires

A method is presented for maximizing the yield and crystal phase purity of vertically aligned Au-assisted GaAs nanowires grown with an SiOx selective area epitaxy mask on GaAs (111)B substrates. The nanowires were grown by the vapor-liquid-solid (VLS) method in a gas source molecular beam epitaxy system. During annealing, Au VLS seeds will alloy with the underlying GaAs substrate and collect beneath the SiOx mask layer. This behavior is detrimental to obtaining vertically aligned, epitaxial nanowire growth. To circumvent this issue, Au droplets were pre-filled with Ga assuring vertical yields in excess of 99%.