A core/shell mechanism for stacking-fault generation in GaAs nanowires

Generation of stacking faults (SFs) during the growth of nanowires (NWs) is a major concern for the efficiency of NW-based devices such as solar cells. Here, molecular-dynamics simulation of a [111]-oriented gallium arsenide NW reveals an atomistic mechanism of SF generation. Spatial distribution of the adatom energy on the (111)B top surface exhibits a core/shell structure due to the contraction of atomic bonds at the sidewall surfaces, where SFs are preferentially nucleated in the shell. A nucleation growth model incorporating the core/shell mechanism suggests a size and growth-condition controlled approach for SF-free growth of NWs. VC 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3703765]