Strain-Enhanced Thermoelectric Performance in GeS2 Monolayer

Abstract

Strain engineering has attracted extensive attention as a valid method to tune the physical and chemical properties of two-dimensional (2D) materials. Here, based on first-principles calculations and by solving the semi-classical Boltzmann transport equation, we reveal that the tensile strain can efficiently enhance the thermoelectric properties of the GeS2 monolayer. It is highlighted that the GeS2 monolayer has a suitable band gap of 1.50 eV to overcome the bipolar conduction effects in materials and can even maintain high stability under a 6% tensile strain. Interestingly, the band degeneracy in the GeS2 monolayer can be effectually regulated through strain, thus improving the power factor. Moreover, the lattice thermal conductivity can be reduced from 3.89 to 0.48 W/mK at room temperature under 6% strain. More importantly, the optimal ZT value for the GeS2 monolayer under 6% strain can reach 0.74 at room temperature and 0.92 at 700 K, which is twice its strain-free form. Our findings provide an exciting insight into regulating the thermoelectric performance of the GeS2 monolayer by strain engineering.

Electrical contact properties of 2D metal-semiconductor heterojunctions composed of different phases of NbS₂ and GeS₂

“…Gao 等人研究了 Pd 修饰 GeS 2 单层的吸附 行为及电子、光学和气敏特性 [25]. Ruan 等人研究发现拉伸应变可提高单层 GeS 2 的热电性能 [26] . Mao 等人研究了双层 GeS 2 在外加电场和应变下对其结构、电子和光学性质的影响 [27] .…”

Tensile strain and finite size modulation of low lattice thermal conductivity in monolayer TMDCs (HfSe2 and ZrS2) from first-principles: a comparative study

“…10,11 In addition to the application environments of devices, strain engineering, as the simplest adjustment method, has been widely used in the regulation of the thermoelectric properties of two-dimensional materials. [12][13][14] In particular, recent studies have shown that for monolayer HfSe 2 , the optimal thermoelectric figure of merit ZT max can be increased from 0.16 to 2.41 under p-type doping and 0.53 to 1.91 under n-type doping by strain engineering. 15 The good tunability of the thermoelectric properties of monolayer HfSe 2 indicates that it has great application potential in the field of thermoelectricity.…”