Lasing in ZnS nanowires grown on anodic aluminum oxide templates

High-density and uniform-sized gold particle arrays have been prepared electrochemically on anodic aluminum oxide (AAO) templates. The gold particles were used as catalysts to synthesize $\mathrm{ZnS}$ nanowires. The as-grown nanowires had a wurtzite single-crystal structure and were aligned perpendicularly to the AAO template. Under high-power density optical excitation $\left(266\mathrm{nm}\right)$ , the nanowire array showed an intense, narrow [full width at half maximum (FWHM) of $2.2\mathrm{nm}$ ] photoluminescent peak at $338\mathrm{nm}$ composed of a superposition of optical resonant modes (FWHM $\sim 0.3\mathrm{nm}$ ) resulting from the collective emission of a large number of nanowires. These results indicate that the $\mathrm{ZnS}$ nanowires act as optical waveguide resonators.