Insights into optoelectronic, thermodynamic, and thermoelectric properties of novel GePtCh (Ch = S, Se, Te) semiconductors: first-principles perspective

Abstract

Ternary chalcogenides are often studied for their remarkable heat resistance and flexible optical properties. We used the well-known density functional theory and examine the complicated connections between the various physical features of the exclusive GePtCh (Ch = S, Se, and Te) ternary chalcogenides. The valence band is formed by the hybridization of the Ge-s/p/d, Pt-s/p/d, and s-p, se-p, and Te-p orbitals in the energy range of -6.0 eV to 0 eV. The materials under consideration are confirmed as indirect bandgap materials with estimated energy gaps of 1.3 eV, 0.8 eV, and 0.2 eV, respectively. By substituting Se and Te for S reduced the bandgap in these materials. The complex dielectric function's components, absorption coefficients, real optical conductivity, energy loss functions, refractive index, reflectivity, and extinction coefficient, are studied and examined to identify their potential use in optoelectronic applications. The thermodynamic parameters of these ternary systems are calculated by employing the quasi-harmonic Debye model. The materials are suitable for thermoelectric applications, as evidenced by their considerable and outstanding thermoelectric properties. Among the materials, GePtTe possessed the highest absorption, indicating that it is a suitable material for the use in optoelectronic applications.