Li Shijie, Tian Shidai, Yao Yuan, He Meng, Chen Li, Zhang Yan, Zhai Junyi
Center on Nanoenergy Research, School of Physical Science and Technology, Guangxi University, Nanning 530004, China.
CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Micro-Nano Energy and Sensor, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing 100083, China.
Nanomaterials (Basel). 2021 Mar 18;11(3):769. doi: 10.3390/nano11030769.
Rare earth (RE) element-doped two-dimensional (2D) transition metal dichalcogenides (TMDCs) with applications in luminescence and magnetics have received considerable attention in recent years. To date, the effect of RE element doping on the electronic properties of monolayer 2D-TMDCs remains unanswered due to challenges including the difficulty of achieving valid monolayer doping and introducing RE elements with distinct valence and atomic configurations. Herein, we report a unique strategy to grow the Sm-doped monolayer MoS film by using an atmospheric pressure chemical vapor deposition method with the substrate face down on top of the growth source. A stable monolayer triangular Sm-doped MoS was achieved. The threshold voltage of an Sm-doped MoS-based field effect transistor (FET) moved from -12 to 0 V due to the p-type character impurity state introduced by Sm ions in monolayer MoS. Additionally, the electrical performance of the monolayer MoS-based FET was improved by RE element Sm doping, including a 500% increase of the on/off current ratio and a 40% increase of the FET's mobility. The electronic property enhancement resulted from Sm doping MoS, which led internal lattice strain and changes in Fermi energy levels. These findings provide a general approach to synthesize RE element-doped monolayer 2D-TMDCs and to enrich their applications in electrical devices.
近年来，稀土（RE）元素掺杂的二维（2D）过渡金属二硫属化物（TMDCs）在发光和磁性方面的应用受到了广泛关注。迄今为止，由于存在诸如难以实现有效的单层掺杂以及引入具有不同价态和原子构型的稀土元素等挑战，稀土元素掺杂对单层二维过渡金属二硫属化物电子性质的影响仍未得到解答。在此，我们报道了一种独特的策略，即通过使用大气压化学气相沉积法，将衬底面朝下放置在生长源上方来生长掺钐单层MoS薄膜。实现了稳定的单层三角形掺钐MoS。由于单层MoS中Sm离子引入的p型特征杂质态，掺Sm的基于MoS的场效应晶体管（FET）的阈值电压从-12 V移至0 V。此外，通过稀土元素Sm掺杂提高了基于单层MoS的FET的电学性能，包括开/关电流比增加500%以及FET迁移率提高40%。电子性质的增强源于Sm掺杂MoS，这导致了内部晶格应变和费米能级的变化。这些发现为合成稀土元素掺杂的单层二维过渡金属二硫属化物并丰富其在电子器件中的应用提供了一种通用方法。
