Self-assembly of CdS: from nanoparticles to nanorods and arrayed nanorod bundles

The CdS nanoparticles have been assembled into CdS nanorods and arrayed nanorod bundles by a thioglycolic acid (TGA) assisted hydrothermal processes using sodium sulfide (Na2S) and thiourea ((NH2)2CS) as the sulfur source, respectively. High-resolution transmission electron microscopy (HRTEM) shows that the CdS nanorods are single crystalline and the arrayed nanorod bundles are polycrystalline in nature. It is believed that the CdS nanorods were formed through the cluster-to-cluster oriented attachment mechanism, while the CdS nanorods bundles were formed through the particle-to-particle oriented attachment mechanism. In addition, the optical properties of CdS nanostructures were characterized by photoluminescence spectra (PL) and Raman spectroscopy.