Band gap modulation in CdS_xSe_1-x nanowires synthesized by a pulsed laser ablation with the Au catalyst

The synthesis of CdS_xSe_1-x (0<x<1) ternary alloy nanowires on an Au-coated Si substrate by a pulsed laser ablation process in a hot-wall-type chamber was studied. The diameter and length of the synthesized alloyed nanowires were 50-100nm and several tens of micrometres, respectively. X-ray diffraction analysis showed that the resulting nanowires have a hexagonal wurtzite crystalline structure. The diffraction peaks were shifted toward the higher value of 2 as the value of x increases, which indicates that the lattice constant and unit cell volume scales linearly with the composition. Based on the photoluminescence analysis, we found that the direct band gap of the nanowires also changes linearly with the composition, which means that the energy band gap could be systematically modulated in the spectral region from 1.74 to 2.45eV.