Two-Dimensional Buckled Tetragonal cadmium chalcogenides, including CdS, CdSe, and CdTe Monolayers as Photo-catalysts for Water Splitting

Pure hydrogen production via water splitting is an ideal strategy for producing clean and sustainable energy. The two-dimensional (2D) cadmium chalcogenides single-layers with a tetragonal crystal structure, namely Tetra-CdX (X=S,...

Simulation the spectral dependence of the transmittance for semiconductor thin films

The spectral dependence of the transmittance as a function of the film thickness, the refractive index of the substrate, bandgap and the Cauchy parameters (α and β) of the semiconductor material was determined from condition of interference extremes. The absorption coefficient was simulated for the structure – thin film/substrate. Cadmium chalcogenides (CdTe, CdSe, and CdS) deposited on quartz substrates was selected as model samples. Experimental behavior of substrate transmittance was used to determine its refractive index. The theoretical results are compared with the experimental data and shows good agreement.

Optical Properties of Materials for Solar Energy Based on Cadmium Chalcogenides Thin Films

The optical constants and thickness of cadmium chalcogenides (CdX, X= S, Se and Te) thin films prepared by quasi close-space sublimation and high-frequency magnetron sputtering method are determined. The optical constants and the band gap of the films under study have been determined. Optical properties (refractive index n(λ), extinction coefficient k(λ) and dielectric functions ε(λ)) of thin films and thickness d can be determined from the transmission spectrum. The dispersion of the refractive index was explained using a single oscillator model. Single oscillator energy and dispersion energy are obtained from fitting. The material optical parameter such as normalized integrated transmission, zero and high-frequency dielectric constant, density of state effective mass ratio was also calculated.

DFT study of optoelectronic spectra of barium cadmium chalcogenides (Ba2CdX3, X = S, Se and Te)

DFT analyses of electronic and optical spectra of barium cadmium chalcogenides (Ba2CdX3, X = S, Se, Te) have been carried out. The study of electronic spectra has been made in terms of band structure and density of states using full potential linear augmented plane wave plus local orbital method. Band structure calculations have been carried out under the approximations PBE-GGA, PBE-Sol, LDA and TB-mBJ. Band structures of these materials show that Ba2CdS3, Ba2CdSe3 and Ba2CdTe3 crystals possess a band gap less than 1 eV, underestimated relative to the experimental/theoretical literature values. Optical spectra of these chalcogenides have been analyzed in terms of real and imaginary parts of dielectric function, reflectivity, refractive index, extinction coefficient, absorption coefficient, optical conductivity and electron energy loss. Optical results show large anisotropy along different directions. These results provide a physical basis of barium cadmium chalcogenides for potential application in optoelectronic devices.