Synthesis and characterization of CuAlS2 nanoparticles by mechanical milling

Abstract

CuAlS2 chalcopyrite nanocrystalline was successfully synthesized by high energy mechanical milling followed by a homogenization annealing at argon atmosphere. The stoichiometric mixture of elemental Cu, Al, and S powders was mechanically alloyed under argon atmosphere using a high energy ball milling device. The X-ray diffraction patterns indicated that the CuS phase with a hexagonal crystal lattice and interconnected plane morphology forms in the early stage of milling. The Main phase begins at 1 h. With increasing milling time, crystallite size decreased and microstrain increased. The X-ray diffraction patterns of annealed powder at different times and temperatures show increased crystallite size and c/a, and decreased microstrain. The optical direct bandgap values of CuAlS2 nanoparticles were calculated to be about 3.1–3.4 eV. The positive Seebeck coefficient indicates that the dominant carrier holes. The maximum Seebeck coefficient 11.5 μV/K was obtained at 377 ℃.