Etude Des Propriétés Optiques, Structurales Et Vibrationnelles En Infrarouge Des Matériaux Semi-conducteurs En Vue D’application Photovoltaïque

Résumé: In this manuscript, we have studied the structural, elastic, electronic, optical, vibrational and thermodynamic properties under the effect of hydrostatic pressure of chalcopyrite materials of ternary compounds CdXP2 (X = Ge, Si), LiXTe2 (X = Ga, Al) and quaternary Cu2CdGeSe4. The structural optimization and vibrational properties were obtained using the Vienna Ab-initio Simulation Package (VASP) code within the framework of functional density theory (DFT). All calculations were performed under the generalized gradient approximation (GGA) with the Perdew-Burke-Ernzernhof exchange correlation function, the local density approximation (LDA), the gradient approximation generalized improved (GGA-PBESol) and the GGA approximation plus Hubbard's correction (GGA + U). During our study, different structural phases were examined. The structural parameters at the ground state were calculated and compared with the available results. All mesh parameters were estimated for the compounds studied. The elastic constants of these compounds were calculated and used in the study of mechanical stability. An analysis of the dispersion spectra and state densities of the phonons was done in order to verify their dynamic stabilities and understand the contribution of phonons in thermal transport in these materials. In addition, a study on the electronic and optical properties was carried out by calculating the band structures, the charge densities, ... The thermodynamic properties of the materials studied, such as the free energy of Helmholtz F, the internal energy E, entropy S and heat capacity CV, the grünstein parameters were predicted using the quasi-harmonic approximation.

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