Electronic regulation of two-dimensional(2 D)transition metal dichalcogenides(TMDCs)is a crucial step towards next-generation optoelectronics and electronics.Here,we demonstrate controllable and selective-area defect ...Electronic regulation of two-dimensional(2 D)transition metal dichalcogenides(TMDCs)is a crucial step towards next-generation optoelectronics and electronics.Here,we demonstrate controllable and selective-area defect engineering in 2D molybdenum disulfide(MoS_(2))using a focused ion beam with a low-energy gallium ion(Ga^(+))source.We find that the surface defects of MoS_(2)can be tuned by the precise control of ion energy and dose.Furthermore,the fieldeffect transistors based on the monolayer MoS_(2)show a significant threshold voltage modulation over 70 V after Ga+irradiation.First-principles calculations reveal that the Ga impurities in the monolayer MoS_(2)introduce a defect state near the Fermi level,leading to a shallow acceptor level of 0.25 eV above the valence band maximum.This defect engineering strategy enables direct writing of complex pattern at the atomic length scale in a controlled and facile manner,tailoring the electronic properties of 2D TMDCs for novel devices.展开更多
Two-dimensional(2D)materials possess unique thickness-and lateral-size-dependent properties.Many efforts have been devoted to obtaining 2D materials with narrow structure heterogeneity while it is still challenging to...Two-dimensional(2D)materials possess unique thickness-and lateral-size-dependent properties.Many efforts have been devoted to obtaining 2D materials with narrow structure heterogeneity while it is still challenging to independently control their thickness and lateral size,limiting their widespread applications.Here,we develop a three-step method which achieves independent thickness and lateral size sorting of 2D materials.Taking 2D h-BN flakes as an example,their thickness and lateral size are independently sorted to different fractions with thicknesses smaller than 6 nm.In addition,the 2D h-BN flakes possess narrow distributions of both thickness and lateral size.We further develop a force field extraction method and achieve scalable size sorting of 2D h-BN,which is universal for sorting other 2D materials including MoS2 and graphene oxide.This work reports an effective method to produce structure homogenous 2D materials and will help fundamental studies and applications of 2D materials where thickness and lateral size are of concern.展开更多
基金supported by Fujian Minjiang Distinguished Scholar Programthe Department of Science and Technology of Fujian Province(2020J01704 and 2019L3008)the Scientific Research Foundation from Jimei University(ZP2020066 and ZP2020065)。
文摘Electronic regulation of two-dimensional(2 D)transition metal dichalcogenides(TMDCs)is a crucial step towards next-generation optoelectronics and electronics.Here,we demonstrate controllable and selective-area defect engineering in 2D molybdenum disulfide(MoS_(2))using a focused ion beam with a low-energy gallium ion(Ga^(+))source.We find that the surface defects of MoS_(2)can be tuned by the precise control of ion energy and dose.Furthermore,the fieldeffect transistors based on the monolayer MoS_(2)show a significant threshold voltage modulation over 70 V after Ga+irradiation.First-principles calculations reveal that the Ga impurities in the monolayer MoS_(2)introduce a defect state near the Fermi level,leading to a shallow acceptor level of 0.25 eV above the valence band maximum.This defect engineering strategy enables direct writing of complex pattern at the atomic length scale in a controlled and facile manner,tailoring the electronic properties of 2D TMDCs for novel devices.
基金the National Natural Science Foundation of China(51920105002,51991340,and 51991343)Guangdong Innovative and Entrepreneurial Research Team Program(2017ZT07C341)+2 种基金the Bureau of Industry and Information Technology of Shenzhen for the“2017 Graphene Manufacturing Innovation Center Project”(201901171523)Shenzhen Basic Research Project(JCYJ20190809180605522,JCYJ20200109144620815 and JCYJ20200109144616617)China Postdoctoral Science Foundation(2020M680540)。
文摘Two-dimensional(2D)materials possess unique thickness-and lateral-size-dependent properties.Many efforts have been devoted to obtaining 2D materials with narrow structure heterogeneity while it is still challenging to independently control their thickness and lateral size,limiting their widespread applications.Here,we develop a three-step method which achieves independent thickness and lateral size sorting of 2D materials.Taking 2D h-BN flakes as an example,their thickness and lateral size are independently sorted to different fractions with thicknesses smaller than 6 nm.In addition,the 2D h-BN flakes possess narrow distributions of both thickness and lateral size.We further develop a force field extraction method and achieve scalable size sorting of 2D h-BN,which is universal for sorting other 2D materials including MoS2 and graphene oxide.This work reports an effective method to produce structure homogenous 2D materials and will help fundamental studies and applications of 2D materials where thickness and lateral size are of concern.
