NOVEL CdS NANOBELTS FORMED BY NANOPARTICLES: SYNTHESIS, CHARACTERIZATION AND OPTICAL PROPERTIES

In this paper, we report a novel CdS nanobelt formed by nanoparticles and prepared by an accurately designed thermal-evaporating method. The CdS nanobelts present single-crystalline characteristic and their zone axis was along $[2\bar{1}\bar{1}0]$ crystal direction. Based on TEM images, a proper growth mechanism of CdS nanobelts is proposed. The growth of CdS nanobelts follows three steps: (a) CdS nanoparticles with the diameter of ~ 3 nm were formed by reaction of Cd and S atoms at high temperature, (b) nanoparticles aggregated along several specific crystal directions ($[2\bar{1}\bar{1}0]$, $[01\bar{1}0]$ and [0001]) and nanobelt with planar surfaces were formed by an oriented attachment growth, (c) nanoparticles were continuously grown on the surface of nanobelt via a homo-epitaxial route. Two Raman peaks (at 299.0 cm-1 and 603.5 cm-1) of the CdS nanobelts shift toward lower frequency compared with the reported works. A symmetrical intensive peak centered at 2.43 eV was observed in PL spectrum of CdS n...