摩擦力显微镜(friction force microscopy,FFM)是一种基于摩擦力信号的原子力显微镜,能够对二维材料晶格进行快速、无损的高分辨成像.然而,由于热漂移、黏附力、表面静电等因素的影响,环境条件下二维材料的高分辨FFM成像仍面临着巨大挑...摩擦力显微镜(friction force microscopy,FFM)是一种基于摩擦力信号的原子力显微镜,能够对二维材料晶格进行快速、无损的高分辨成像.然而,由于热漂移、黏附力、表面静电等因素的影响,环境条件下二维材料的高分辨FFM成像仍面临着巨大挑战.基于以上问题,本文以高定向热解石墨为标准样品,通过对探针在样品表面黏滑行为的分析,系统研究了探针弹性常数、正应力和扫描速度对高分辨FFM成像的影响,并建立了一套可靠的二维材料晶格结构表征方法.该方法能够获得精确的结构信息,所测得的二维材料晶格常数平均误差小于2.3%.此外,该方法还适用于化学气相沉积法和剥离法制备的多种二维材料,展现出较高的普适性.本文的研究结果为环境条件下二维材料晶格结构的精确表征提供了新思路.展开更多
Two-dimensional(2D)semiconductors have attracted great attention to extend Moore’s law,which motivates the quest for fast growth of high-quality materials.However,taking MoS_(2) as an example,current methods yield 2D...Two-dimensional(2D)semiconductors have attracted great attention to extend Moore’s law,which motivates the quest for fast growth of high-quality materials.However,taking MoS_(2) as an example,current methods yield 2D MoS_(2) with a low growth rate and poor quality with vacancy concentrations three to five orders of magnitude higher than silicon and other commercial semiconductors.Here,we develop a strategy of using an intermediate product of iodine as a transport agent to carry metal precursors efficiently for ultrafast growth of high-quality MoS_(2).The grown MoS_(2) has the lowest density of sulfur vacancies(~1.41×10^(12) cm^(−2))reported so far and excellent electrical properties with high on/off current ratios of 108 and carrier mobility of 175 cm^(2) V^(−1) s^(−1).Theoretical calculations show that by incorporating iodine,the nucleation barrier of MoS_(2) growth with sulfur-terminated edges reduces dramatically.The sufficient supply of precursor and low nucleation energy together boost the ultrafast growth of sub-millimeter MoS_(2) domains within seconds.This work provides an effective method for the ultrafast growth of 2D semiconductors with high quality,which will promote their applications.展开更多
CONSPECTUS:Two-dimensional(2D)compound materials are regarded as promising candidates in many applications,including electronics,optoelectronics,sensors,and flexible devices,because they have high carrier mobility,tun...CONSPECTUS:Two-dimensional(2D)compound materials are regarded as promising candidates in many applications,including electronics,optoelectronics,sensors,and flexible devices,because they have high carrier mobility,tunable bandgaps,large specific surface area,atomic-level thickness,and cover lots of other properties.In order to bring 2D compound materials from the laboratory to industrial applications,materials preparation is the first prerequisite.Among all methods to prepare 2D compound materials,chemical vapor deposition(CVD)is one of the promising methods because it can grow a series of 2D compound materials with high quality as well as reasonable cost.So far,many efforts have been made in the CVD growth of 2D compound materials with large domain size,controllable number of layers,fast growth rate,and high-quality features,etc.Therefore,the CVD method has shown much potential for the commercialization of 2D compound materials.However,due to the complicated growth mechanism like sublimation and diffusion processes of multiple precursors,maintaining the controllability,repeatability,and high quality of CVD-grown 2D compound materials is still a big challenge,which prevents their widespread use.In this Account,taking 2D transition metal dichalcogenides(TMDCs)as examples,we review current progress and highlight some promising growth strategies for the CVD growth of 2D compound materials.In detail,the key technology parameters that affect the CVD process,including non-metal precursor,metal precursor,substrate engineering,temperature,and gas flow,are systematically discussed.In addition,we introduce some emerging methods in improving the quality of CVD-grown 2D compound materials(e.g.,repairing the sulfur vacancies by thiol chemistry).Then the current understanding of the CVD growth mechanism is summarized and discussed.In the end,we conclude the current challenges and propose the potential opportunities in this field in terms of the growth of novel 2D compound materials(e.g.,p-type materials,2D materials with high carrier mobility,2D materials with wide bandgaps in the ultraviolet regime or narrow bandgaps in the infrared regime,and 2D nonlayered materials),the post-treatment of CVD-grown samples to obtain new 2D materials and heterostructures,and the exploration of the exotic 2D physics and their promising applications.Overall,we believe this review will guide the future design of controllable CVD systems for the growth of 2D compound materials with good controllability and high quality,laying the foundations for their potential applications.展开更多
文摘摩擦力显微镜(friction force microscopy,FFM)是一种基于摩擦力信号的原子力显微镜,能够对二维材料晶格进行快速、无损的高分辨成像.然而,由于热漂移、黏附力、表面静电等因素的影响,环境条件下二维材料的高分辨FFM成像仍面临着巨大挑战.基于以上问题,本文以高定向热解石墨为标准样品,通过对探针在样品表面黏滑行为的分析,系统研究了探针弹性常数、正应力和扫描速度对高分辨FFM成像的影响,并建立了一套可靠的二维材料晶格结构表征方法.该方法能够获得精确的结构信息,所测得的二维材料晶格常数平均误差小于2.3%.此外,该方法还适用于化学气相沉积法和剥离法制备的多种二维材料,展现出较高的普适性.本文的研究结果为环境条件下二维材料晶格结构的精确表征提供了新思路.
基金This work was supported by the National Key R&D Program(2018YFA0307300)the National Natural Science Foundation of China(51991343,51991340,52188101 and 51920105002)+3 种基金the China Postdoctoral Science Foundation(2021M701948)the National Science Fund for Distinguished Young Scholars(52125309)Guangdong Innovative and Entrepreneurial Research Team Program(2017ZT07C341)Shenzhen Basic Research Project(JCYJ20200109144616617 and JCYJ20220818101014029).
文摘Two-dimensional(2D)semiconductors have attracted great attention to extend Moore’s law,which motivates the quest for fast growth of high-quality materials.However,taking MoS_(2) as an example,current methods yield 2D MoS_(2) with a low growth rate and poor quality with vacancy concentrations three to five orders of magnitude higher than silicon and other commercial semiconductors.Here,we develop a strategy of using an intermediate product of iodine as a transport agent to carry metal precursors efficiently for ultrafast growth of high-quality MoS_(2).The grown MoS_(2) has the lowest density of sulfur vacancies(~1.41×10^(12) cm^(−2))reported so far and excellent electrical properties with high on/off current ratios of 108 and carrier mobility of 175 cm^(2) V^(−1) s^(−1).Theoretical calculations show that by incorporating iodine,the nucleation barrier of MoS_(2) growth with sulfur-terminated edges reduces dramatically.The sufficient supply of precursor and low nucleation energy together boost the ultrafast growth of sub-millimeter MoS_(2) domains within seconds.This work provides an effective method for the ultrafast growth of 2D semiconductors with high quality,which will promote their applications.
基金supported by the National Science Fund for Distinguished Young Scholars(52125309)the National Natural Science Foundation of China(51991343,51920105002,51991340,52188101,and 11974156)+3 种基金Guangdong Innovative and Entrepreneurial Research Team Program(2017ZT07C341 and 2019ZT08C044)the Bureau of Industry and Information Technology of Shenzhen for the “2017 Graphene Manufacturing Innovation Center Project”(201901171523)Shenzhen Basic Research Project(JCYJ20200109144616617 and JCYJ20190809180605522)Shenzhen Science and Technology Program(KQTD20190929173815000 and 20200925161102001)。
基金We acknowledge support from the National Natural Science Foundation of China(Nos.51722206,51991340,51991343,and 51920105002)the Youth 1000-Talent Program of China,the National Key R&D Program(2018YFA0307200)+1 种基金Guangdong Innovative and Entrepreneurial Research Team Program(No.2017ZT07C341)the Bureau of Industry and Information Technology of Shenzhen for the“2017 Graphene Manufacturing Innovation Center Project”(No.201901171523).
文摘CONSPECTUS:Two-dimensional(2D)compound materials are regarded as promising candidates in many applications,including electronics,optoelectronics,sensors,and flexible devices,because they have high carrier mobility,tunable bandgaps,large specific surface area,atomic-level thickness,and cover lots of other properties.In order to bring 2D compound materials from the laboratory to industrial applications,materials preparation is the first prerequisite.Among all methods to prepare 2D compound materials,chemical vapor deposition(CVD)is one of the promising methods because it can grow a series of 2D compound materials with high quality as well as reasonable cost.So far,many efforts have been made in the CVD growth of 2D compound materials with large domain size,controllable number of layers,fast growth rate,and high-quality features,etc.Therefore,the CVD method has shown much potential for the commercialization of 2D compound materials.However,due to the complicated growth mechanism like sublimation and diffusion processes of multiple precursors,maintaining the controllability,repeatability,and high quality of CVD-grown 2D compound materials is still a big challenge,which prevents their widespread use.In this Account,taking 2D transition metal dichalcogenides(TMDCs)as examples,we review current progress and highlight some promising growth strategies for the CVD growth of 2D compound materials.In detail,the key technology parameters that affect the CVD process,including non-metal precursor,metal precursor,substrate engineering,temperature,and gas flow,are systematically discussed.In addition,we introduce some emerging methods in improving the quality of CVD-grown 2D compound materials(e.g.,repairing the sulfur vacancies by thiol chemistry).Then the current understanding of the CVD growth mechanism is summarized and discussed.In the end,we conclude the current challenges and propose the potential opportunities in this field in terms of the growth of novel 2D compound materials(e.g.,p-type materials,2D materials with high carrier mobility,2D materials with wide bandgaps in the ultraviolet regime or narrow bandgaps in the infrared regime,and 2D nonlayered materials),the post-treatment of CVD-grown samples to obtain new 2D materials and heterostructures,and the exploration of the exotic 2D physics and their promising applications.Overall,we believe this review will guide the future design of controllable CVD systems for the growth of 2D compound materials with good controllability and high quality,laying the foundations for their potential applications.
