Patil Sukanya B, Sankeshwar N S, Mulimani B G
Department of Physics, Karnatak University, Dharwad, Karnataka 580003, India.
J Phys Condens Matter. 2017 Dec 6;29(48):485303. doi: 10.1088/1361-648X/aa91a0.
A theoretical study of the electronic properties, namely, electrical conductivity (EC), electronic thermal conductivity (ETC) and thermoelectric power (TEP) in 2D MoS monolayers (MLs), over a wide range of temperatures (10 < T < 300 K), is presented employing Boltzmann transport formalism. Considering the electrons to be scattered by screened charged impurities and the acoustic, optical and remote phonons, the transport equation is solved using Ritz iterative method. Numerical calculations of EC, ETC and TEP presented for supported and free-standing MLs with high electron concentrations, as a function of temperature, bring out the relative importance of the various scattering mechanisms operative. The role of CIs, with regard to both concentration and separation from the substrate-ML interface, in determining the properties of supported MLs is demonstrated for the first time. Validity of Wiedemann-Franz law and Mott formula are examined for supported and free standing MLs. Calculations are in consonance with recent experimental data on mobility and TEP of exfoliated SiO-supported MoS ML samples. In the case of TEP it is found that though the diffusion contribution is dominant the inclusion of the drag component, incorporating contributions from all relevant phonon scattering mechanisms, is needed to obtain good agreement with the data.
采用玻尔兹曼输运形式，对二维硫化钼单层（MLs）在较宽温度范围（10 < T < 300 K）内的电子性质，即电导率（EC）、电子热导率（ETC）和热电功率（TEP）进行了理论研究。考虑电子被屏蔽带电杂质以及声学、光学和远程声子散射，使用里兹迭代法求解输运方程。给出了具有高电子浓度的支撑和独立MLs的EC、ETC和TEP随温度变化的数值计算结果，揭示了各种起作用的散射机制的相对重要性。首次证明了带电杂质（CIs）在浓度以及与衬底-ML界面间距方面对支撑MLs性质的影响。研究了支撑和独立MLs的维德曼-弗兰兹定律和莫特公式的有效性。计算结果与最近关于剥离的SiO支撑的MoS ML样品迁移率和TEP的实验数据一致。对于TEP，发现虽然扩散贡献占主导，但需要包含拖曳分量（纳入所有相关声子散射机制的贡献）才能与数据取得良好一致。
