GaAs nanowhiskers grown by molecular beam epitaxy on GaAs(111)B surface activated by Au: theory and experiment

GaAs nanowhiskers are grown by molecular beam epitaxy (MBE) on the GaAs(111)B surface activated by Au at different conditions (Au layer thickness, GaAs flux, substrate temperature, effective thickness of deposited GaAs) and characterized by scanning electron microscopy technique. The dependence of the nanowhisker height on the size of Au- GaAs alloy drops is investigated. A kinetic model of nanowhiskers formation in the vapor-liquid-solid growth mechanism is proposed. In particular, the nanowhiskers growth rate is found as a function of the drop size, system energetics, and MBE growth conditions. The predictions of a theoretical model are compared to the results of experimental observations. It is demonstrated that the MBE method enables one to fabricate nanowhiskers ensembles with tunable structural properties (height, lateral size distribution, surface density) by changing the Au layer thickness, the amount of deposited GaAs, and MBE growth conditions.