Template-directed selective growth of ordered ZnO nanostructures on GaN by the hydrothermal method

Ordered ZnO nanostructures are synthesized through nanolithographically patterned templates on GaN by using the hydrothermal method. Due to the confined nucleation sites, ZnO nanostructures are selectively grown and replicate the geometry and dimension of the nanopatterns. The as-grown ZnO nanostructures have doughnut-like profiles, indicating preferred nucleation at the nanopattern edges driven by the surface energy minimization. Variation of ZnO nanostructure morphologies with varying nanopattern sizes is observed, and the growth mechanism is discussed. Room-temperature photoluminescence spectra show strong near band-edge emission at 381 nm. This method can be used to fabricate ordered ZnO nanostructures with tunable shape, size and morphology.