Synthesis and lasing properties of highly ordered CdS nanowire arrays

Highly ordered large-area arrays of wurtzite CdS nanowires are synthesized on Cd-foil substrates via a simple liquid reaction route using thiosemicarbazide and Cd foil as the starting materials. The CdS nanowires are single crystals growing along the [001] direction and are perpendicular to the surface of the substrate. The characteristic Raman peaks of CdS are red-shifted and show asymmetric broadening, which is ascribed to phonon confinement effects arising from the nanoscale dimensions of the nanowires, Significantly, the uniform CdS nanowire arrays can act as laser cavities in the visible-light range, leading to bandgap lasing at ca. 515 nm with obvious modes. The high density of nuclei and the preferential growth direction induce the formation of aligned CdS nanowires on the metal substrate.