Role of the Au/GaAs(111) interface on the wurtzite-structure formation during GaAs nanowire growth by a vapor-liquid-solid mechanism

An ab initio study on the formation of GaAs layers with wurtzite structure during GaAs nanowire growth is performed for Au/GaAs(111) interfaces. The calculations reveal that Au atoms can be incorporated and stabilize the wurtzite structure at the Au/GaAs(111)B interface. The zinc-blende structure, in contrast, is favorable at the Au/GaAs(111)A interface, implying that wurtzite segments such as rotational twins can be formed only when the GaAs(111)B substrate is used to fabricate GaAs nanowires by vapor-solid-liquid (VLS) growth. The stabilization of wurtzite structure originates from the hybridization between incorporated Au and interfacial As atoms which enhances the electrostatic interaction between anions and cations of GaAs layers. The results provide a possible explanation for wurtzite-structure formation in GaAs nanowires by the VLS growth on the GaAs(111)B substrate.