Thin films of Sb2S3 doped by Sm3+ ions

Abstract

Pure and Sm3+ doped amorphous thin films of Sb2S3 were prepared by thermal co-evaporation of Sb2S3 and Sm metal. The prepared films contained a slight over-stoichiometric excess of Sb. From transmittance measurement, the absorption edge, index of refraction, n, thickness, d, optical gap, Egopt, relative permittivity, εr, single oscillator energy, Eo, dispersion energy, Ed, and the values of third-order nonlinear susceptibility χ(3) were evaluated. The values of χ(3) increase with Sm doping. Some of above-mentioned values are slightly influenced by exposure of films to a UV lamp. The Raman spectra revealed two main structural units in the films: SbS3 pyramids and Sb–Sb bonds in S2Sb–SbS2 structural units. Three luminescence bands were found. The first one with maximum near 1130 nm can be assigned to 6F9/2→6H5/2 and/or 6F11/2→6H7/2 electron transitions, which are overlapping. The second band can be assigned to the electron transition 6F11/2→6H9/2 or 6F9/2→6H7/2 or 6F7/2→6H5/2. The third luminescence band with maximum near 1500 nm can be probably assigned to the electron transition 6F11/2→6H11/2.