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Mechanical buckling induced periodic kinking/stripe microstructures in mechanically peeled graphite fla es from HOPG 被引量:1
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作者 Manrui Ren Ze Liu +1 位作者 Quan-shui Zheng Jefferson Zhe Liu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2015年第4期494-499,共6页
Mechanical exfoliation is a widely used method to isolate high quality graphene layers from bulk graphite. In our recent experiments, some ordered microstructures, consisting of a periodic alternation of kinks and str... Mechanical exfoliation is a widely used method to isolate high quality graphene layers from bulk graphite. In our recent experiments, some ordered microstructures, consisting of a periodic alternation of kinks and stripes, were observed in thin graphite flakes that were mechanically peeled from highly oriented pyrolytic graphite. In this paper, a theoretical model is presented to attribute the formation of such ordered structures to the alternation of two mechanical processes during the exfoliation: (1) peeling of a graphite flake and (2) mechanical buckling of the flake being sub- jected to bending. In this model, the width of the stripes L is determined by thickness h of the flakes, surface energy Y, and critical buckling strain ecr. Using some appropriate values of y and ecr that are within the ranges determined by other inde- pendent experiments and simulations, the predicted relations between the stripe width and the flake thickness agree reason- ably well with our experimental measurements. Conversely, measuring the L-h relations of the periodic microstructures in thin graphite flakes could help determine the critical mechan- ical buckling strain εcr and the interface energy γ. 展开更多
关键词 HOPG mechanical exfoliation Periodic microstructures KINKING mechanical buckling
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Friction characteristics of mechanically exfoliated and CVD-grown single-layer MoS_2 被引量:11
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作者 Dinh Le Cao KY Bien-Cuong TRAN KHAC +2 位作者 Chinh Tam LE Yong Soo KIM Koo-Hyun CHUNG 《Friction》 SCIE CSCD 2018年第4期395-406,共12页
In this work, the friction characteristics of single-layer MoS2 prepared with chemical vapor deposition (CVD) at three different temperatures were quantitatively investigated and compared to those of single-layer Mo... In this work, the friction characteristics of single-layer MoS2 prepared with chemical vapor deposition (CVD) at three different temperatures were quantitatively investigated and compared to those of single-layer MoS2 prepared using mechanical exfoliation. The surface and crystalline qualities of the MoS2 specimens were characterized using an optical microscope, atomic force microscope (AFM), and Raman spectroscopy. The surfaces of the MoS2 specimens were generally flat and smooth. However, the Raman data showed that the crystalline qualities of CVD-grown single-layer MoS2 at 800 ℃ and 850 ℃ were relatively similar to those of mechanically exfoliated MoS2 whereas the crystalline quality of the CVD-grown single-layer MoS2 at 900 ℃ was lower. The CVD-grown single-layer MoS2 exhibited higher friction than mechanically exfoliated single-layer MoS2, which might be related to the crystalline imperfections in the CVD-grown MoS2. In addition, the friction of CVD-grown single-layer MoS2 increased as the CVD growth temperature increased. In terms of tribological properties, 800 ℃ was the optimal temperature for the CVD process used in this work. Furthermore, it was observed that the friction at the grain boundary was significantly larger than that at the grain, potentially due to defects at the grain boundary. This result indicates that the temperature used during CVD should be optimized considering the grain size to achieve low friction characteristics. The outcomes of this work will be useful for understanding the intrinsic friction characteristics of single-layer MoS2 and elucidating the feasibility of single-layer MoS2 as protective or lubricant layers for micro- and nano-devices. 展开更多
关键词 atomic force microscope chemical vapor deposition grain boundary FRICTION mechanical exfoliation MoS2
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Antistatic PVC-graphene Composite through Plasticizer-mediated Exfoliation of Graphite 被引量:7
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作者 Zi-Bo Wei Yang Zhao +3 位作者 Chao Wang Shigenori Kuga Yong Huang Min Wu 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2018年第12期1361-1367,共7页
Multilayer graphene was prepared by mechanical exfoliation of natural graphite with dioctyl phthalate (DOP) as milling medium without solvent. The obtained mixture could be directly mixed with poly(vinyl chloride)... Multilayer graphene was prepared by mechanical exfoliation of natural graphite with dioctyl phthalate (DOP) as milling medium without solvent. The obtained mixture could be directly mixed with poly(vinyl chloride) (PVC) for melt-forming, with DOP acting as plasticizer and graphene acting as conductive filler for antistatic performance. The composite showed surface resistance of 2.5 ×10 6 Ω/ at 1 wt% carbon additive, significantly lower than approx. 7 wt% of raw graphite required for achieving the same level. This value is low enough for practical antistatic criterion of 3 × 10 8 Ω/ . The effect of filler addition on mechanical performance was minimal, or even beneficial for the milled carbon in contrast to the case of raw graphite. 展开更多
关键词 Antistatic composite Poly(vinyl chloride) GRAPHENE mechanical exfoliation Electrical property
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Exfoliation of 2D van der Waals crystals in ultrahigh vacuum for interface engineering
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作者 Zhenyu Sun Xu Han +11 位作者 Zhihao Cai Shaosheng Yue Daiyu Geng Dongke Rong Lin Zhao Yi-Qi Zhang Peng Cheng Lan Chen Xingjiang Zhou Yuan Huang Kehui Wu Baojie Feng 《Science Bulletin》 SCIE EI CSCD 2022年第13期1345-1351,M0004,共8页
Two-dimensional(2D)materials and their heterostructures have been intensively studied in recent years due to their potential applications in electronic,optoelectronic,and spintronic devices.Nonetheless,the realization... Two-dimensional(2D)materials and their heterostructures have been intensively studied in recent years due to their potential applications in electronic,optoelectronic,and spintronic devices.Nonetheless,the realization of 2D heterostructures with atomically flat and clean interfaces remains challenging,especially for air-sensitive materials,which hinders the in-depth investigation of interface-induced phenomena and the fabrication of high-quality devices.Here,we circumvented this challenge by exfoliating 2D materials in an ultrahigh vacuum.Remarkably,ultraflat and clean substrate surfaces can assist the exfoliation of 2D materials,regardless of the substrate and 2D material,thus providing a universal method for the preparation of heterostructures with ideal interfaces.In addition,we studied the properties of two prototypical systems that cannot be achieved previously,including the electronic structure of monolayer phospherene and optical responses of transition metal dichalcogenides on different metal substrates.Our work paves the way to engineer rich interface-induced phenomena,such as proximity effects and moirésuperlattices. 展开更多
关键词 2D van der Waals crystals Ultrahigh vacuum mechanical exfoliation Interface engineering Universal method
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Mechanically exfoliated MoS_(2) nanosheets decorated with SnS_(2) nanoparticles for high-stability gas sensors at room temperature 被引量:9
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作者 Jia-Bei Liu Jin-Yong Hu +3 位作者 Can Liu Yu-Ming Tan Xiang Peng Yong Zhang 《Rare Metals》 SCIE EI CAS CSCD 2021年第6期1536-1544,共9页
Due to its unique physical,chemical and surface electronic properties,molybdenum disulfide(MoS_(2))nanosheets open up a new avenue for nitrogen dioxide(NO2)detection at room temperature.Nevertheless,the gas sensing pr... Due to its unique physical,chemical and surface electronic properties,molybdenum disulfide(MoS_(2))nanosheets open up a new avenue for nitrogen dioxide(NO2)detection at room temperature.Nevertheless,the gas sensing properties of pure MoS_(2) nanosheets are inevitably degenerated by the adsorption of atmospheric oxygen,which results in weak stability for MoS_(2)-based gas sensors.Reducing surface defects and constructing heterojunctions may be effective strategies to improve the gas sensing properties of MoS_(2) nanosheets.In this work,we design a novel nanocomposite based on MoS_(2) nanosheets decorated with tin disulfide(SnS_(2))nanoparticles(MoS_(2)/SnS_(2))via combining the mechanical exfoliation method with the facile hydrothermal method.The experimental results indicate that,after surfaces decoration with SnS_(2) nanoparticles,the as-prepared gas sensor based on MoS_(2)/SnS_(2) nanocomposites exhibits reliable long-term stability with the maximum response value drift of less than 3%at room temperature.Moreover,the MoS_(2)/SnS_(2) sensor also possesses desirable gas sensing properties upon NO_(2) at room temperature,such as high sensitivity,rapid response/recovery speed(28 s/3 s,5×10^(-6) NO_(2)),satisfactory selectivity,favorable repeatability and reversibility.The improved gas sensing properties of MoS_(2)/SnS_(2) nanocomposites can be attributed to the unique electronic properties of MoS 2 nanosheets with the fewer layers structure and the competitive adsorption effect of SnS_(2) nanoparticles.This work elucidates that SnS_(2) nanoparticles serving as an effective antioxidative decoration can promote the stability of MoS_(2) nanosheets,providing a promising approach to achieve high-stability NO2 gas sensors at room temperature. 展开更多
关键词 mechanically exfoliated MoS2 nanosheets MoS_(2)/SnS_(2)nanocomposites NO2 sensing properties Room-temperature detection
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Fast response speed of mechanically exfoliated MoS2 modified by PbS in detecting NO2 被引量:4
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作者 Junjiang Tan Jinyong Hu +4 位作者 Jianxu Ren Jinfeng Peng Can Liu Yiqiao Song Yong Zhang 《Chinese Chemical Letters》 SCIE CAS CSCD 2020年第8期2103-2108,共6页
MoS2,acting as a promising gas sensing material,has shown huge potential in monitoring of toxic and harmful gases at room temperature.However,MoS2-based gas sensors still suffer from poor gas sensing performance such ... MoS2,acting as a promising gas sensing material,has shown huge potential in monitoring of toxic and harmful gases at room temperature.However,MoS2-based gas sensors still suffer from poor gas sensing performance such as poor sensitivity,long response time.Constructing the hete ro structure is an effective approach to improve gas-sensing performance of MoS2.Herein,PbS@MoS2 composites synthesized by mechanical exfoliation combining with wet-chemical precipitation are used to investigate its performance in detecting NO2 at room temperature.The response value of PbS@MoS2 gas sensor against NO2 is significantly improved compared with the pure MoS2 gas sensor.At the same time,the modification with PbS also accelerates the response speed of MoS2,and the response time is almost reduced by two orders of magnitude,from hundreds of seconds to less than ten seconds.The enhanced response value and fast response time are mainly benefited from the modulation effect of NO2 to PbS@MoS2 heterostructure and the mechanically exfoliated MoS2 surface with few defects.This work can be expected to provide useful guidance for designing composite materials with excellent gas sensing properties. 展开更多
关键词 mechanically exfoliated MoS2 nanosheets PbS@MoS2 heterostructure Fast response speed Room-temperature detection NO2 sensing properties
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Tunable passively Q-switched ytterbium-doped fiber laser with mechanically exfoliated GaSe saturable absorber 被引量:2
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作者 H.Ahmad S.N.Aidit +1 位作者 S.I.Ooi Z.C.Tiu 《Chinese Optics Letters》 SCIE EI CAS CSCD 2018年第2期93-97,共5页
A tunable passively Q-switched ytterbium-doped fiber laser using few-layer gallium selenide(GaSe) as a saturable absorber(SA) is demonstrated.The few-layer GaSe SA,which is fabricated by the mechanical exfoliation... A tunable passively Q-switched ytterbium-doped fiber laser using few-layer gallium selenide(GaSe) as a saturable absorber(SA) is demonstrated.The few-layer GaSe SA,which is fabricated by the mechanical exfoliation method,is able to generate a Q-switched fiber laser that has a maximum repetition rate of 92.6 kHz and a minimum pulsed width of 2.3 μs.The highest pulse energy exhibited by the generated pulse is 18.8 nJ with a signal to noise ratio of ~40 dB.The tunability of the proposed laser covers from 1042 to 1082 nm,giving a tuning range of 40 nm. 展开更多
关键词 Tunable passively Q-switched ytterbium-doped fiber laser with mechanically exfoliated GaSe saturable absorber SA
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An efficient route to prepare suspended monolayer for feasible optical and electronic characterizations of two-dimensional materials 被引量:1
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作者 Yuan Huang Yun-Kun Wang +18 位作者 Xin-Yu Huang Guan-Hua Zhang Xu Han Yang Yang Yunan Gao Lei Meng Yushu Wang Guang-Zhou Geng Li-Wei Liu Lin Zhao Zhi-Hai Cheng Xin-Feng Liu Ze-Feng Ren Hui-Xia Yang Yufeng Hao Hong-Jun Gao Xing-Jiang Zhou Wei Ji Ye-Liang Wang 《InfoMat》 SCIE CAS 2022年第2期126-138,共13页
Two-dimensional(2D)materials are highly sensitive to substrates,interfaces,and the surrounding environments.Suspended 2D materials are free from substrate-induced effects,thus an ideal approach to study their intrinsi... Two-dimensional(2D)materials are highly sensitive to substrates,interfaces,and the surrounding environments.Suspended 2D materials are free from substrate-induced effects,thus an ideal approach to study their intrinsic properties.However,it is very challenging to prepare large-area suspended 2D materials with high efficiency.Here we report a universal method,based on pretreatments of densely patterned hole array substrates with either oxygenplasma or gold film deposition,to prepare large-area suspended mono-and few-layer 2D materials.Multiple structural,optical,and electrical characterization tools were used to fully evaluate the improved performance of various suspended 2D layers.Some of these observations reported in this study are:(1)Observation of a new Raman low frequency mode for the suspended MoS_(2);(2)Significantly stronger photoluminescence(PL)and second harmonic generation(SHG)signals of suspended WSe_(2),which enables the study of new optical transition processes;(3)The low energy electron diffraction pattern on suspended MoS_(2) also exhibits much sharper spots than that on the supported area;and(4)The mobility of suspended graphene device approaches 300000 cm^(2) V^(-1) s^(-1),which is desirable to explore the intrinsic properties of graphene.This work provides an innovative and efficient route for fabricating suspended 2D materials,and we expect that it can be broadly used for studying intrinsic properties of 2D materials and in applications of hybrid active nanophotonic and electronic devices. 展开更多
关键词 mechanical exfoliation PHOTOLUMINESCENCE Raman spectrum suspended 2D materials
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