Formation and Characterization of Cd2S3 Polycrystalline Films onto Glass and Lanthanum Substrates

In this article, the structural, optical and dielectric properties of the rarely investigated Cd2S3 thin films are reported. Particularly, Cd2S3 thin films prepared by the thermal evaporation technique onto glass, and 150-nm-thick lanthanum transparent substrate studied by means of energy-dispersive structural analysis have shown that the Cd2S3 thin films are of polycrystalline nature. The hexagonal unit cell parameters, which slightly differ from that of CdS, increased upon replacement of glass with lanthanum. All the other structural parameters including the grain size, strain and defect density are accordingly affected. While the optical band gap increased when La replaces glass, the high-frequency dielectric constant decreased. On the other hand, the Drude–Lorentz modeling of the dielectric spectra has shown that the La/Cd2S3 thin films are promising materials for production of thin film transistors as they exhibit drift mobility values of  13.3 cm2/Vs. The response of the glass/ Cd2S3 and La/Cd2S3 interfaces to the incident electromagnetic light is associated with hole-plasmon interactions that are limited by plasmon frequency values in the range of 0.4–8.1 GHz. Such property makes this material attractive as microwave band pass/reject filters.