低温下二硫化钼电子迁移率研究

二硫化钼(MoS₂)是已知的二维半导体材料中光电性能最优秀的材料之一. 单原子层厚的MoS₂是禁带宽度为1.8 eV 的二维直接带隙半导体材料, 可以用来发展新型的纳米电子器件和光电功能器件. 本论文利用玻尔兹曼平衡方程输运理论研究低温时MoS₂系统的电输运性质, 计算得到了MoS₂电子迁移率的解析表达式. 研究发现, 低温时MoS₂ 的迁移率与衬底材料的介电常数的平方成正比; 与系统的电子浓度对带电杂质的浓度的比率n_e/n_i 成线性关系. 因此, 选用介电常数高的衬底材料, 适当提高MoS₂系统的载流子浓度, 同时降低杂质的浓度, 可以有效提高MoS₂系统的迁移率. 研究结果为探索以MoS₂为基础的新型纳米光电器件的研究和实际应用提供了理论依据. 关键词： 二硫化钼 迁移率 电输运 平衡方程

Investigation on mobility of single-layer MoS2 at low temperature

The two-dimensional, single-layer MoS₂ with a direct band-gap of 1.8 eV, which makes it very suitable for nanoelectronic applications, such as field-effect transistors, has aroused great interest because of its distinctive electronic, optical, and catalytic properties. In this paper, we present a detailed theoretical study of the electronic transport property of single-layer MoS₂ on the basis of the usual momentum-balance equation. We obtain the analytical electric mobility at low temperature. It shows that the electric mobility of MoS₂ is linear with respect to substrate dielectric constant squared and the rate between the electron density and charged impurity density at low temperature. It is found that by using relatively high dielectric constant materials as substrates, reducing impurity densities and increasing carrier densities high mobilities in MoS₂-substrate wafer systems can be achieved.
Keywords： 2')" href="#">MoS₂ mobility electronic transport balance-equation