Zhang Xiankun, Liao Qingliang, Kang Zhuo, Liu Baishan, Liu Xiaozhi, Ou Yang, Xiao Jiankun, Du Junli, Liu Yihe, Gao Li, Gu Lin, Hong Mengyu, Yu Huihui, Zhang Zheng, Duan Xiangfeng, Zhang Yue
Beijing Advanced Innovation Center for Materials Genome Engineering, Beijing Key Laboratory for Advanced Energy Materials and Technologies, University of Science and Technology Beijing, Beijing, 100083, P. R. China.
State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China.
Adv Mater. 2021 Feb;33(7):e2007051. doi: 10.1002/adma.202007051. Epub 2021 Jan 14.
Monolayer 2D semiconductors (e.g., MoS ) are of considerable interest for atomically thin transistors but generally limited by insufficient carrier mobility or driving current. Minimizing the lattice defects in 2D semiconductors represents a common strategy to improve their electronic properties, but has met with limited success to date. Herein, a hidden benefit of the atomic vacancies in monolayer 2D semiconductors to push their performance limit is reported. By purposely tailoring the sulfur vacancies (SVs) to an optimum density of 4.7% in monolayer MoS , an unusual mobility enhancement is obtained and a record-high carrier mobility (>115 cm V s ) is achieved, realizing monolayer MoS transistors with an exceptional current density (>0.60 mA µm ) and a record-high on/off ratio >10 , and enabling a logic inverter with an ultrahigh voltage gain >100. The systematic transport studies reveal that the counterintuitive vacancy-enhanced transport originates from a nearest-neighbor hopping conduction model, in which an optimum SV density is essential for maximizing the charge hopping probability. Lastly, the vacancy benefit into other monolayer 2D semiconductors is further generalized; thus, a general strategy for tailoring the charge transport properties of monolayer materials is defined.
单层二维半导体（例如，二硫化钼）对于原子级薄的晶体管具有相当大的吸引力，但通常受到载流子迁移率不足或驱动电流的限制。最小化二维半导体中的晶格缺陷是提高其电子性能的常见策略，但迄今为止成效有限。在此，报道了单层二维半导体中原子空位的一个潜在好处，即推动其性能极限。通过在单层二硫化钼中将硫空位（SVs）特意调整到4.7%的最佳密度，获得了异常的迁移率增强，并实现了创纪录的高载流子迁移率（>115 cm² V⁻¹ s⁻¹），实现了具有出色电流密度（>0.60 mA µm⁻¹）和创纪录高的开/关比>10⁵的单层二硫化钼晶体管，并实现了具有超高电压增益>100的逻辑反相器。系统的输运研究表明，这种违反直觉的空位增强输运源于最近邻跳跃传导模型，其中最佳的硫空位密度对于最大化电荷跳跃概率至关重要。最后，将空位的好处进一步推广到其他单层二维半导体；因此，定义了一种调整单层材料电荷输运特性的通用策略。
