Light emission from ZnSe nanowires

Arrays of free-standing ZnSe nanowires of length 8-10 μm and diameter 60-150 nm were fabricated by Au-catalyzed vapor-liquid-solid growth. Electron microscopy showed that these were high quality single crystal nanowires. Photoluminescence (PL) measurements of the as-grown nanowires were characterized by weak near band edge emission and strong defect-related emission. The effect of post-growth annealing on the PL spectra under both Zn-rich and Se-rich conditions were studied. Annealing under a Zn-rich atmosphere was found to significantly enhance the near band edge emission and suppress deep-level emission, resulting in spectra dominated by the near band edge emission. On the other hand, annealing in a Se-rich atmosphere had the reverse effect, resulting in spectra dominated by deep level emission.