Abstract

CuS nanocrystals in hexagonal structure have been synthesized by mechanical alloying the elemental Cu and S powders. CuS compound was formed through the reaction of Cu + S → CuS, which was initiated only 100 seconds after the mechanical alloying process started. XRD pattern suggests that pure CuS nanocrystals in hexagonal structure were obtained after mechanical alloying process was carried out for 40 hours. The as-milled CuS nanocrystals were subsequently capped with organic-inorganic compsite ligand of trioctylphosphine oxide / trioctylphosphine / nitric acid (TOPO/TOP/NA). The morphology of the as-milled and capped CuS nanocrystals has been studied by transmission electron microscope (TEM). The size of capped CuS nanocrystals ranges from 2 nm to 10 nm. The capped CuS nanocrystals show similar optical properties to the CuS nanocrystals prepared by wet chemical process, the absorption peaks for capped CuS nanocrystals locate within the wavelength range of 656 to 665 nm.

Keywords: CuS nanocrystals, Mechanical alloying, Optical properties, Microstructure