Control of growth orientation for epitaxially grown ZnSe nanowires

ZnSe nanowires (NWs) were grown on (111) (100), and (110)-oriented GaAs substrates by molecular-beam epitaxy via the vapor-liquid-solid reaction. The size dependence of NW growth orientation was studied by varying the Au catalyst size. Through detailed transmission electron microscopy studies, it was found that <111> orientation is the growth direction for NWs with size ≥30 nm, while NWs with size around 10 nm prefer to grow along the <110> direction, with a small portion along the <112> direction. These observations have led to the realization of vertical ZnSe NWs with size around 10 nm grown on a GaAs(110) substrate