Shenzhen Key Laboratory of Special Functional Materials, Shenzhen Engineering Laboratory for Advanced Technology of Ceramics, Guangdong Research Centre for Interfacial Engineering of Functional Materials, College of Materials Science and Engineering, Institute of Deep Underground Sciences and Green Energy, Shenzhen University, Shenzhen 518060, P. R. China.
Nanoscale. 2019 Oct 10;11(39):18116-18123. doi: 10.1039/c9nr04176a.
Inspired by the experimental growth of two-dimensional (2D) tellurene (Yixin et al., Nat. Electron, 2018, 1, 228-236) and the recent study of unusually low thermal conductivity of atomically thin 2D tellurium (Jie Ren et al., Nanoscale, 2018, 10, 12997), we carried out systematic calculations for monolayer β-tellurene, focusing on its electrical transport and electronic and thermoelectric properties by means of density functional theory (DFT) combined with deformation potential theory and Boltzmann transport theory. We have found that monolayer β-tellurene exhibits a band gap of 1.5 eV. The carrier transport is highly direction-temperature-dependent, with a high room-temperature transport mobility of 1343 cm2 V-1 s-1 and a relaxation time of 283 fs in the armchair direction for hole transport at room-temperature. It is coincidently favourable in the armchair direction for both the Seebeck coefficient and the electrical conductivity, making the p-type monolayer β-tellurene a highly promising thermoelectric candidate. With a low intrinsic lattice thermal conductivity, the maximum figure of merit (ZT) is 2.9 and 0.84 along the armchair and zigzag directions for p-type doping at 700 K, respectively. The predicted properties demonstrate that monolayer β-tellurene can be a prospective material towards thermoelectric applications.
受二维碲（Yixin 等人，Nat. Electron.，2018，1，228-236）实验生长以及最近关于原子薄二维碲异常低热导率的研究（Jie Ren 等人，Nanoscale，2018，10，12997）的启发，我们通过密度泛函理论（DFT）结合变形势理论和玻尔兹曼输运理论，对单层β-碲烯进行了系统的计算，重点研究了其电输运和电子及热电性质。我们发现，单层β-碲烯具有 1.5 eV 的带隙。载流子输运具有高度的各向异性温度依赖性，室温下空穴在扶手椅方向的迁移率高达 1343 cm2 V-1 s-1，弛豫时间为 283 fs。室温下，在扶手椅方向上，Seebeck 系数和电导率都很有利，使得 p 型单层β-碲烯成为一种很有前途的热电候选材料。由于本征晶格热导率低，在 700 K 时 p 型掺杂时，沿扶手椅和锯齿形方向的最大品质因数（ZT）分别为 2.9 和 0.84。预测的性质表明，单层β-碲烯可能是一种有前途的热电应用材料。
