Analysis of the core–shell interface between zinc-blende GaP and wurtzite ZnO

Abstract

Core–shell GaP/ZnO nanowires (NWs) were prepared in a two-step process: (1) GaP NWs were grown on GaP substrate by low-pressure metalorganic vapour phase epitaxy using 30nm Au seeds as nucleation centres, (2) the GaP NWs were covered in a thin nanocrystalline Ga-doped ZnO layer by sputtering in a Perkin Elmer planar RF diode system. Electrical contacts were processed to individual GaP/ZnO NWs using electron beam lithography, evaporation and lift-off of metallic layers: Au/Zn (GaP core) and Au/Al (ZnO shell). Electrical and photocurrent measurement of the NWs confirmed that a radial pn heterojunction was formed between the GaP core and ZnO shell.