Mobility engineering and a metal-insulator transition in monolayer MoS2
Mobility engineering and a metal-insulator transition in monolayer MoS2
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DOI：
10.1038/nmat3687
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发表时间：
2013-09-01
期刊：
影响因子：
41.2
通讯作者：
Kis, Andras
中科院分区：
文献类型：
--
作者：
Radisavljevic, Branimir;Kis, Andras
二维 (2D) 材料是一类新型材料，具有有趣的物理特性和从纳米电子学到传感和光子学的应用。除了石墨烯（研究最多的二维材料）之外，其他层状材料（例如半导体二硫化物 MoS2 或 WSe2）的单层作为场效应晶体管（FET）的有前途的沟道材料也越来越重要。由于量子力学限制，单层 MoS2 中存在直接带隙，使得室温 FET 的开/关比超过 10(8)。这些器件中高卡伯电介质的存在增强了它们的迁移率，但其机制尚不清楚。在此，我们报告了不同介电配置中 MoS2 FET 的电传输测量结果。迁移率对温度的依赖性清楚地表明，具有顶栅电介质的双栅器件中带电杂质散射受到强烈抑制。同时，声子散射表现出比预期更弱的温度依赖性。双栅器件中实现的高水平掺杂还允许观察单层 MoS2 中由于强电子-电子相互作用而产生的金属-绝缘体转变。我们的工作为进一步提高二维半导体性能开辟了道路，并将 MoS2 作为研究介观系统相关效应的有趣系统。
Two-dimensional (2D) materials are a new class of materials with interesting physical properties and applications ranging from nanoelectronics to sensing and photonics. In addition to graphene, the most studied 2D material, monolayers of other layered materials such as semiconducting dichalcogenides MoS2 or WSe2 are gaining in importance as promising channel materials for field-effect transistors (FETs). The presence of a direct bandgap in monolayer MoS2 due to quantum-mechanical confinement allows room-temperature FETs with an on/off ratio exceeding 10(8). The presence of high-kappa dielectrics in these devices enhanced their mobility, but the mechanisms are not well understood. Here, we report on electrical transport measurements on MoS2 FETs in different dielectric configurations. The dependence of mobility on temperature shows clear evidence of the strong suppression of charged-impurity scattering in dual-gate devices with a top-gate dielectric. At the same time, phonon scattering shows a weaker than expected temperature dependence. High levels of doping achieved in dual-gate devices also allow the observation of a metal-insulator transition in monolayer MoS2 due to strong electron-electron interactions. Our work opens up the way to further improvements in 2D semiconductor performance and introduces MoS2 as an interesting system for studying correlation effects in mesoscopic systems.