Thermoelectric Properties Of Two-dimensional Gallium Telluride

Thermoelectric materials can realize the conversion of thermal energy to electrical energy,and have always had a strong interest and demand in the energy industry.Research in recent years has shown that two-dimensional thermoelectric materials usually have a significant improvement/change in performance compared to corresponding bulk materials.In terms of experiments,high-performance thermoelectric materials can be used in two-dimensional photodetectors to improve their characteristics.Through stress modulation of two-dimensional thermoelectric materials,it also shows good application prospects such as flexible electronics and photoelectric dimmable detectors.The research content of this paper includes:(1)Phonon,electronic and thermoelectric transport properties of two-dimensional(2D)GaTe with hexagonal structure and monoclinic structure are investigated in this article.Stability of these structures are confirmed by phonon dispersion calculations.The hexagonal structure shows better thermoelectric properties because of its lower thermal conductivity,higher electrical conductivities and Seebeck coefficients.The maximum value of the figure of merit(ZT)for GaTe reaches 0.85 for hexagonal structure when T=1100 K.(2)The stress modulation mechanism of two-dimensional GaTe is studied.We apply uniaxial and biaxial strains(from-10%to 10%)to 2D GaTe,the changes in the two-dimensional GaTe band gap,total energy and bond length under uniaxial and biaxial stress are analyzed.Based on the changes in the energy band diagram and the band gap under different stress conditions,the stresses applied to the machine along different directions are summarized.Influence of properties and electronic properties,the Young's modulus of the single-layer GaTe along the x-direction is 12.2 GPa,and the Young's modulus along the y-direction is 20.7 GPa.We also calculated that the Poisson's ratios of the axial strains applied in the x and y directions were 0.93 and 0.3,respectively.These all explain the anisotropy of GaTe.GaTe's band structure exhibits direct-indirect band gap and semiconductor-metal transitions when 12%compressive stress is added to the x-axis and 10%compressive stress is added to the biaxial.