Fabrication and characterization of Sn:CdS films for optical-nonlinear-limiting applications

Herein, we are focusing on to inveterate physical properties of spray pyrolysis fabricated CdS films with diverse Sn doping contents (0.0, 0.5, 1.0, 2.5, 5.0 wt%) named as Sn:CdS. Hexagonal mono-phase of CdS at every content of Sn was detected by structural and vibrational analyses. The mean size of crystallites (L-ave), density of dislocations, strain, number of unit cells and texture coefficient were estimated and the values of L-ave are observed in 20-24 nm range. To confirm the presence of Sn and its homogeneity in films the EDX/SEM mapping was carried out. Fine nanostructured and pin hole/crack free films fabrication was suggested by SEM images. The grown Sn:CdS films are showing the transparency in 50-70% range in visible to INR range. The refractive index values were calculated in 1.6-2.9 range, over 500-2500 nm wavelength region. The estimated values of E-g are noticed in 2.43-2.45 eV range. At two excitation wavelengths the PL emission was recorded at both 350 and 450 nm excitation wavelength and possesses an emission at similar to 531 +/- 20 and 530 +/- 15 nm (green), correspondingly. The values of optical dielectric constant, conductivity, linear, third order- nonlinear susceptibilities and index of nonlinear refraction were estimated. Using a 650 nm wavelength laser the optical limiting was recorded and noticed to be strongly affected by Sn doping.