Multicolored ZnO Nanowire Architectures on Trenched Silicon Substrates

Well-tailored three-dimensional (3D) ZnO nanowire architectures have been successfully grown on Si microtrenches fabricated using nanoimprinting lithography by a low-temperature hydrothermal approach. Au nanoparticles or ZnO nanofilms were used as templates to tailor the orientation ordered nanowire growth normal to the microtrench surface. Au produced sparse nanowire growth, while ZnO seeds created densely packed growth. Optically, other than displaying a primary color when viewed from one incident angle, the 3D nanowire architecture periodically displayed multiple primary color domains covering all microtrenches and the local orientation ordered nanowire arrays. A pre-growth annealing of ZnO nanoseeds resulted in nonuniformity and non-periodic distribution of the grown nanoarchitectures and thus reduced the multicolor effect.