The electronic, thermoelectric and optical properties of Janus In2STe monolayer: A first-principles investigation

Abstract

In this present work, comprehensive investigations of the electronic structure, thermoelectric and optical properties of the Janus In2STe monolayer have been performed using density functional theory combined with the semi-classical Boltzmann transport theory. A direct bandgap semiconductor has been predicted for Janus In2STe monolayer. Compared to the InS and InTe monolayers, it is observed that the electrical conductivity was enhanced for the Janus In2STe monolayer, reaching 10.81×1019(Ω−1m−1s−1) with small p-type doping. At room temperature, our calculations predicted high Seebeck coefficients and electronic figure of merit for InS, InTe and Janus In2STe monolayers. Of interest, the Janus In2STe monolayer exhibited the highest Seebeck coefficient value of around 1110 μV/K, with an electronic figure of merit of 0.97, indicating its high potential for thermoelectric applications. Moreover, we have addressed the optical properties such as dielectric constant, refractive index, reflectivity, extinction coefficient, and absorption coefficient, versus the energy for InS, InTe, and Janus In2STe monolayers. The predicted absorption coefficient in the visible region was found to be high with a value of 107 cm−1, showing the future potential applications of InS, InTe, and Janus In2STe monolayers in optoelectronic and optical devices.