First-principles investigation of InAgASe4 (A = Ge, Sn) quaternary chalcogenides: Unveiling electronic, optical, and thermoelectric features

Direct band gap quaternary semiconductors possess exclusive characteristics, such as tunable optoelectronic qualities and decent thermal stability. Employing the recognized density functional theory, we investigated the complex interaction between the electronic, optical, and thermoelectric properties of quaternary InAgASe4 (A = Ge, Sn) semiconductors. The involvement of various energy states is explained by density of state calculations. The In-s/p, Sn-s/p, Ge-s/p, and Se-p orbitals constitute the conduction band area near the Gamma-point. To know about the probable usage in optoelectronic applications, the significant optical parameters are calculated and analyzed. The materials display an isotropic crystal structure, which suggests that all crystallographic directions exhibit the same physical attributes, it also possesses an isotropic optical response. The studied systems are appropriate for thermoelectric applications, as demonstrated by noteworthy and remarkable thermoelectric properties. In both materials, the carrier concentration and power factor are constant within a certain temperature range of 50 K to 300 K. The studied materials also display an increase in the power factor just after 300 K.