Aging effect on the structure and optical properties of nano Cu2S films

Abstract

The amorphous nature is the dominant state of the as deposited Cu2S films. Films were aged for 3, 6 and 12 months. The aged films of 12 months are poly crystalline within nano scale. (1 0 2), (1 1 0), (1 0 3) and (1 1 2) were the preferred orientations of 12 months of aging. The calculated crystallite sizes were 13, 29, 33 and 54 nm respectively. The optical gap is direct; it increases with the increasing of aging time as well as oscillation energy and constant A. Refractive index, the infinity dielectric constant, the lattice dielectric constant the real and the imaginary part of the dielectric constant, the ratio of carrier concentration to the effective mass, the dispersion energy are decreasing with the increasing of aging time. Optical conductivity and energy loss function were studied; both decrease by the increasing of aging time.