Thermoelectric properties of two-dimensional GaTe bilayer

Abstract

Investigation of thermoelectric (TE) properties on two-dimensional (2D) materials attracts intensive research efforts due to its potential environment-friendly applications. We explore the TE properties of 2D bilayer GaTe. The GaTe bilayer has an indirect bandgap of 1.35 eV. The maximum Seebeck coefficient is 1550 µV/K regardless of the direction and doping type. The relaxation time has anisotropic behavior. In the n-type system, the armchair direction relaxation time is longer than the zig-zag direction. The p-type relaxation time has no directional dependency and shorter than that of n-type. Also, the n-type relaxation time is longer than that of the p-type. This anisotropic relaxation time in n-type system generates larger electrical conductivity and electronic thermal conductivity in the n-type armchair direction. The lattice thermal conductivity has no directional dependency and is larger than the electronic thermal conductivity. Overall, we obtain the maximum figure of merit (ZT) of ~ 0.82 in the n-type at 700 K.