Kim Taesoo, Fan Sidi, Lee Sanghyub, Joo Min-Kyu, Lee Young Hee
Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Sungkyunkwan University, Suwon, 16419, Republic of Korea.
Department of Energy Science, Department of Physics, Sungkyunkwan University, Suwon, 16419, Republic of Korea.
Sci Rep. 2020 Aug 4;10(1):13101. doi: 10.1038/s41598-020-70038-6.
Monolayer molybdenum disulfide (MoS) possesses a desirable direct bandgap with moderate carrier mobility, whereas graphene (Gr) exhibits a zero bandgap and excellent carrier mobility. Numerous approaches have been suggested for concomitantly realizing high on/off current ratio and high carrier mobility in field-effect transistors, but little is known to date about the effect of two-dimensional layered materials. Herein, we propose a Gr/MoS heterojunction platform, i.e., junction field-effect transistor (JFET), that enhances the carrier mobility by a factor of ~ 10 (~ 100 cm V s) compared to that of monolayer MoS, while retaining a high on/off current ratio of ~ 10 at room temperature. The Fermi level of Gr can be tuned by the wide back-gate bias (V) to modulate the effective Schottky barrier height (SBH) at the Gr/MoS heterointerface from 528 meV (n-MoS/p-Gr) to 116 meV (n-MoS/n-Gr), consequently enhancing the carrier mobility. The double humps in the transconductance derivative profile clearly reveal the carrier transport mechanism of Gr/MoS, where the barrier height is controlled by electrostatic doping.
单层二硫化钼（MoS）具有理想的直接带隙和适中的载流子迁移率，而石墨烯（Gr）则呈现零带隙和优异的载流子迁移率。为了在场效应晶体管中同时实现高开/关电流比和高载流子迁移率，人们已经提出了许多方法，但迄今为止，关于二维层状材料的影响却知之甚少。在此，我们提出了一种Gr/MoS异质结平台，即结型场效应晶体管（JFET），与单层MoS相比，其载流子迁移率提高了约10倍（约100 cm² V⁻¹ s⁻¹），同时在室温下保持约10的高开/关电流比。Gr的费米能级可通过宽背栅偏压（V）进行调节，以调制Gr/MoS异质界面处的有效肖特基势垒高度（SBH），从528 meV（n-MoS/p-Gr）调至116 meV（n-MoS/n-Gr），从而提高载流子迁移率。跨导导数曲线中的双峰清楚地揭示了Gr/MoS的载流子传输机制，其中势垒高度由静电掺杂控制。
