Vertically aligned ZnO/amorphous-Si core–shell heterostructured nanowire arrays

We report the synthesis of vertically aligned ZnO/a-Si core–shell nanowire arrays (ZnO nanowires coated with amorphous silicon) through chemical vapor deposition. The core–shell heterostructured nanowires possessed uniform morphology and the thickness of the amorphous silicon shells could be controlled easily by tuning the deposition duration and temperature. The core–shell heterostructured nanowires exhibited enhanced antireflection and absorption performance as well as tunable PL properties. Because the individual ZnO/a-Si nanowires showed p-type characteristics and the ZnO cores were n-type semiconductors, the core–shell nanowires formed p–n junctions naturally.