Investigation of layer-dependent electronic, optical and thermoelectric transport properties of α-In2Se3 based on first principles calculations

Abstract

Here, the electronic, optical and thermoelectric transport properties are studied using DFT for the bulk and the monolayer α-In₂Se₃. The electronic bandgap is observed to be 1.36 eV for the monolayer and 1.25 eV for the bulk α-In₂Se₃ using HSE06 hybrid functional. The optical properties such as the dielectric constant, absorption coefficient, refractive index, birefringence, reflectivity, energy loss functions and optical conductivity were also studied for the bulk and the monolayer of α-In₂Se₃. It was also observed that bulk α-In₂Se₃ exhibits a Seebeck coefficient of 850 μV/K and 1056 μV/K for monolayer α-In₂Se₃ at 300 K indicating it as a potential room temperature layered thermoelectric material. Further, the electronic part of figure of merit, ZT_e found to reach 103 for monolayer α-In₂Se₃ and 104 for bulk α-In₂Se₃ at 300 K. Further, the total figure of merit, ZT was found to be 1.64 for the n-type monolayer α-In₂Se₃ at 300 K. The present work highlights the promising application of α-In₂Se₃ in next generation sub-nm scale optoelectronic and thermoelectric devices.