CaS: Ce, Sm films were fabricated by a sol-gel method, subsequently annealed at 500 οC for 1 hr in N2 atmosphere. The optimum mole ratio of C2H4(OH)2 to Ca2+ is 2 : 1. The XRD results show that CaS: Ce, Sm is face-centered cubic structure and the lattice constant increases 0.07 Å along all directions. Its diffraction peak has a certain broadening and moves to small angel, which is due to the surface effect of the nano particles. The AFM results show that the average grain size of CaS: Ce, Sm films is 30 nm and the grain size distribution is uniform. The strong emission peaking at 626 nm with 420 nm as excitation light corresponds to the 6H5/2→ 4M19/2(6P, 4P)5/2 transition.

Keywords: CaS: Ce, Sm, Sol-gel method, Luminescent spectrum