Electronic structure, optical and thermoelectric properties of Ge2SeS monolayer via first-principles study

Abstract The electronic, optical and thermoelectric properties of the Ge 2SeS monolayer were detailed using the first-principle calculations. The dynamic stability of the Ge2SeS structure monolayer has been confirmed by the phonon dispersion curve. Our electronic calculations indicate that the Ge2 SeS monolayer is a semiconductor at equilibrium state with an indirect bandgap lower/larger than that of the GeS/GeSe monolayer calculated by generalized gradient approximation (GGA) of Perdew Burke Ernzerhof (PBE) functional. The optical properties such as dielectric constant, reflectivity , extinction coefficient, and absorption coefficient versus the energy were investigated. In addition, the thermoelectric properties are obtained using the semi-classical Boltzmann transport theory. The results show a large Seebeck coefficient of 2470 μV/K at 300K, the electronic figure of merit ( ZTe) is 0.91 in Ge2SeS monolayer at 300 K. The predicted optical and thermoelectric properties could make the Ge2SeS monolayer a potential candidate for applications in optoelectronic and energy conversion technologies at room temperature.