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High harmonic exploring on different materials in dynamic atomic force microscopy

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Science China(Technological Sciences) 2018年第3期61卷 446-452页

作者： ZHENG ZhiYue XU Rui YE ShiLi HUSSAIN Sabir JI Wei cheng Peng LI YanJun SUGAWARA Yasuhiro cheng zhihai CAS Center for Excellence in Nanoscience and Key Laboratory of Standardization and Measurement for Nanotechnology National Center for Nanoscience and Technology Beijing 100190 China Department of Physics Renmin University of China Beijing 100872 China The State Key Laboratory of Digital Manufacturing Equipment and Technology Department of Instrument Science and Technology School of Mechanical Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China University of Chinese Academy of Sciences Belting 100049 China Asylum Research Santa Barbara 93117 USA Department of Applied Physics Graduate School of Engineering Osaka University Osaka 565-0871 Japan

In atomic force microscopy(AFM), high-frequency components consisted in dynamic tip-sample interaction have been recently demonstrated as a promising technique for exploring more extensive material properties. Here we present an exploratory study of high harmonic atomic force microscopy by force-spectroscopy and high harmonic imaging. Since these components are very weak compared to the fundamental response, we firstly designed a high harmonic cantilever by tuning the second order flexural resonance frequency to an integer 6 times of its fundamental mode(i.e. ω_2=6ω_1). Moreover, it is verified that high harmonic can discern extra features than topographies on different samples with amplitude/frequency modulation(AM/FM) dynamic AFM mode. In AM mode, the first resonance amplitude and 6 th harmonic amplitude were discussed. The 6 th harmonic is more sensitive than the first order response. In FM mode, it is noted that the decaying rate of the 6 th harmonic frequency is approximately 6 multiples to the slope of the fundamental frequency shift when the tip approaches to the surface of sample. This non-destructive method was also adopted to investigate the local interlayer coupling and intercalation in the two-dimensional graphene films tentatively.

关键词： high harmonic AFM high harmonic cantilever dynamic AFM

Orientation of molecular interface dipole on metal surface investigated by noncontact atomic force microscopy

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Chinese Science Bulletin 2013年第30期58卷 3630-3635页

作者： YUAN BingKai CHEN Pengcheng ZHANG Jun cheng zhihai QIU XiaoHui WANG Chen National Center for Nanoscience and Technology

We investigated the orientations of interface dipole moments of individual non-planar titanyl phthalocyanine(TiOPc)molecules on Cu(111)and Cu(100)substrates using scanning tunneling microscope(STM)and noncontact atomic force microscope(NC-AFM).The dipole moment orientations corresponding to two different configurations of individual TiOPc molecules were determined *** correlation between the actual molecular structures and the corresponding STM topographies is proposed based on the sub-molecular resolution imaging and local contact potential difference(LCPD)*** with the pristine substrate,the LCPD shift due to the adsorption of non-planar molecule is dependent on the permanent molecular dipole,the charge transfer between the surface and the molecule,and the molecular *** work would shed light on tailoring interfacial electronic properties and controlling local physical properties via polar molecule adsorption.

关键词：原子力显微镜分子结构非接触式金属表面偶极子界面 Cu(100) Cu(111)

Advanced atomic force microscopies and their applications in two-dimensional materials:a review

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Materials Futures 2022年第3期1卷 105-143页

作者： Rui Xu Jianfeng Guo Shuo Mi Huanfei Wen Fei Pang Wei Ji zhihai cheng Beijing Key Laboratory of Optoelectronic Functional Materials&Micro-nano Devices Department of PhysicsRenmin University of ChinaBeijing 100872People’s Republic of China Key Laboratory of Instrument Science and Dynamic Testing North University of ChinaTaiyuan 030051People’s Republic of China Key Laboratory of Quantum Sensing and Precision Measurement Institute of Instrument and ElectronicsNorth University of ChinaTaiyuan 030051People’s Republic of China

Scanning probe microscopy(SPM)allows the spatial imaging,measurement,and manipulation of nano and atomic scale surfaces in real *** the last two decades,numerous advanced and functional SPM methods,particularly atomic force microscopy(AFM),have been developed and applied in various research fields,from mapping sample morphology to measuring physical ***,we review the recent progress in functional AFM methods and their applications in studies of two-dimensional(2D)materials,particularly their interfacial physical properties on the *** review can inspire more exciting application works using advanced AFM modes in the 2D and functional materials fields.

关键词： atomic force microscopy advanced atomic force microscopy two-dimensional materials surface and interface

Atmospheric Degradation and Performance Recovery of Two-Dimensional MoS2 Field Effect Transistor

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Chinese Journal of Chemistry 2023年第21期41卷 2832-2836页

作者： Lifei Sun Zhixing Lu Rui Xu Zhewei Li Guanchen Xu Fengen Chen zhihai cheng Liying Jiao Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education Department of ChemistryTsinghua UniversityBeijing100084 China Beijing Key Laboratory of Optoelectronic Functional Materials&Micro-nano Devices Department of PhysicsRenmin University of ChinaBeijing100872 China Advanced Materials Institute Qilu University of Technology(Shandong Academy of Sciences)JinanShandong250000 China

Two-dimensional(2D)transition metal dichalcogenides(TMDCs)showed great potentials in 2D nanoelectronic devices due to their abundant and unique *** performance stability of the 2D TMDCs devices turns into one of the keys for their practical applications but has been rarely ***,we investigated stability of MoS_(2)devices in ambient condition and contributed the device performance degradation to the surface oxidation of the contact metals with low work function,which increased the contact barrier and hindered the electron *** developed a new approach to recover the performance of the aged devices through the selective doping of contacts with organolithium,which prolonged the lifetime of MoS_(2)*** work not only provides important insights into the stability of 2D TMDCs devices,but also opens up a new avenue for optimizing the performance of 2D MoS_(2)devices.

关键词： MoS_(2) Field effect transistor Atmospheric degradation Performance recovery Semiconductors Doping Oxidation

Local electrical charac terization of t wo-dimensional mat erials with functional atomic force microscopy

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Frontiers of physics 2019年第3期14卷 85-105页

作者： Sabir Hussain Kunqi Xu Shili Ye Le Lei Xinmeng Liu Rui Xu Liming Xie zhihai cheng CAS Key Laboratory of Standardization and Measurement for Nanotechnology CAS Center for Excellence in Nanoscience National Center for Nanoscience and Technology Beijing 100190 China Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-nano Devices Renmin University of China Beijing 100872 China University of Chinese Academy of Sciences Beijing 100049 China

Research about two-dimensional (2D) materials is growing exponentially across various scientific and engineering disciplines due to the wealth of unusual physical phenomena that occur when charge transport is confined to a plane. The applications of 2D materials are highly affected by the electrical properties of these mat erials, including curren t dist ribution, surface pot ential, dielectric response, conductivity, perm计tivity, and piezoelectric response. Hence, it is very crucial to characterize these properties at the nanoscale. The Atomic Force Microscopy (AFM)-based techniques are powerful tools that can simultaneously characterize morphology and electrical properties of 2D materials with high spatial resolution, thus being more and more extensively used in this research field. Here, the principles of these AFM techniques are reviewed in detail. After that, their representative applications are further demonstrated in the local characterization of various 2D materials? elcctrical properties.

关键词： advanced AFM techniques nanoscale characteTization electrical properties 2D materials

Direct Imaging of Molecular Orbitals of Metal Phthalocyanines on Metal Surfaces with an O2-Functionalized Tip of a Scanning Tunneling Microscope

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Nano Research 2011年第6期4卷 523-530页

作者： zhihai cheng Shixuan Du Wei Guo Li Gao Zhitao Deng Nan Jiang Haiming Guo Hao Tang H. J. Gao Institute of Physics Chinese Academy of Sciences RO. Box 603 Beijing 100190 China Center for Material Elaboration and Structural Studies B.P. 94347 31055 Toulouse Cedex France

High-resolution scanning tunneling microscope images of iron phthalocyanine and zinc phthalocyanine molecules on Au（111） have been obtained using a functionalized tip of a scanning tunneling microscope （STM）, and show rich intramolecular features that are not observed using clean tips. Ab initio density functional theory calculations and extended Huckel theory calculations revealed that the imaging of detailed electronic states is due specifically to the decoration of the STM tip with O2. The detailed structures are differentiated only when interacting with the highly directional orbitals of the oxygen molecules adsorbed on a truncated, [111]-oriented tungsten tip. Our results indicate a method for increasing the resolution in generic scans and thus, have potential applications in fundamental research based on high-resolution electronic states of molecules on metals, concerning, for example, chemical reactions, and catalysis mechanisms.

关键词： High-resolution scanning tunneling microscope (STM) imaging functionalized STM tip metal phthalocyanines molecular orbital density functional theory calculation

Tuning the morphology of chevron-type graphene nanoribbons by choice of annealing temperature

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Nano Research 2018年第12期11卷 6190-6196页

作者： Yun Cao Jing Qi Yan-Fang Zhang Li Huang Qi Zheng Xiao Lin zhihai cheng Yu-Yang Zhang Xinliang Feng Shixuan Du Sokrates T.Pantelides Hong-Jun Gao Institute of Physics &University of Chinese Academy of Sdences Chinese Academy ofSdencesBeijing 100190China Department of Physics Renmin University of ChinaBeijing 100872China Department of Physics and Astronomy and Department of Electrical Engineering and Computer Science Vanderbilt UniversityNashvilleTennessee 37235USA Center for Advancing Electronics Dresden (cfaed)&Department of Chemistry and Food Chembtry Technische Universitat DresdenD-O 1069DresdenGermany School of Chemistry and Chemical Engineering Shanghai jiao Tong UniversityShanghai200240China

Bottom-up synthesis of graphene nanoribbons (GNRs) by surface-assisted polymerization and cyclodehydrogenation of specifically designed precursor monomers has been shown to yield precise edges and doping. Here we use a precursor monomer containing sulfur atoms to fabricate nanostructures on a Au(111) surface at different annealing temperatures. The nanostructures have distinct configurations, varying from sulfur-doped polymers to sulfur-doped chevron-type GNRs (CGNRs) and, finally, pristine graphene nanoribbons with specific edges of periodic five-member carbon rings. Non-contact atomic force microscopy provides clear evidence for the cleavage of C-S bonds and formation of pristine CGNRs at elevated annealing temperatures. First-principles calculations show that the CGNRs exhibit negative differential resistance.

关键词： chevron-type graphene nanoribbon C-S bond cleavage negative differential resistance scanning tunneling microscopy (STM) noncontact atomic force microscopy (NC-AFM) first-principles calculations

Two ultra-stable novel allotropes of tellurium few-layers

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Chinese Physics B 2020年第9期29卷 458-463页

作者： Changlin Yan Cong Wang Linwei Zhou Pengjie Guo Kai Liu Zhong-Yi Lu zhihai cheng Yang Chai Anlian Pan Wei Ji School of Physics and Electronics Hunan UniversityChangsha 410082China Beijing Key Laboratory of Optoelectronic Functional Materials&Micro-Nano Devices Department of PhysicsRenmin University of ChinaBeijing 100872China The Hong Kong Polytechnic University Hung HomKowloonHong KongChina Key Laboratory for Micro-Nano Physics and Technology of Hunan Province College of Materials Science and EngineeringHunan UniversityChangsha 410082China

At least four two-or quasi-one-dimensional allotropes and a mixture of them were theoretically predicted or experimentally observed for low-dimensional Te,namely theα,β,γ,δ,and chiral-α+δ*** them theγandαphases were found to be the most stable phases for monolayer and thicker layers,***,we found two novel low-dimensional phases,namely theεandζ***ζphase is over 29 meV/Te more stable than the most stable monolayerγphase,and theεphase shows comparable stability with the most stable monolayerγ*** energetic difference between theζandαphases reduces with respect to the increased layer thickness and vanishes at the four-layer(12-sublayer)thickness,while this thickness increases under change ***εandζphases are metallic chains and layers,***ζphase,with very strong interlayer coupling,shows quantum well states in its layer-dependent *** results provide significantly insight into the understanding of polytypism in Te few-layers and may boost tremendous studies on properties of various few-layer phases.

关键词： two-dimensional materials Te density functional theory

Epitaxial growth of antimony nanofilms on HOPG and thermal desorption to control the film thickness

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Chinese Physics B 2020年第9期29卷 164-171页

作者： Shuya Xing Le Lei Haoyu Dong Jianfeng Guo Feiyue Cao Shangzhi Gu Sabir Hussain Fei Pang Wei Ji Rui Xu zhihai cheng Beijing Key Laboratory of Optoelectronic Functional Materials&Micro-nano Devices Department of PhysicsRenmin University of ChinaBeijing 100872China CAS Key Laboratory of Standardization and Measurement for Nanotechnology CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing 100190China University of Chinese Academy of Sciences Beijing 100039China

Group-V elemental nanofilms were predicted to exhibit interesting physical properties such as nontrivial topological properties due to their strong spin-orbit coupling,the quantum confinement,and surface *** was reported that the ultrathin Sb nanofilms can undergo a series of topological transitions as a function of the film thickness h:from a topological semimetal(h>7.8 nm)to a topological insulator(7.8 nm>h>2.7 nm),then a quantum spin Hall(QSH)phase(2.7 nm>h>1.0 nm)and a topological trivial semiconductor(h<1.0 nm).Here,we report a comprehensive investigation on the epitaxial growth of Sb nanofilms on highly oriented pyrolytic graphite(HOPG)substrate and the controllable thermal desorption to achieve their specific *** morphology,thickness,atomic structure,and thermal-strain effect of the Sb nanofilms were characterized by a combination study of scanning electron microscopy(SEM),atomic force microscopy(AFM),and scanning tunneling microscopy(STM).The realization of Sb nanofilms with specific thickness paves the way for the further exploring their thickness-dependent topological phase transitions and exotic physical properties.

关键词： epitaxial growth antimony films scanning tunneling microscope(STM) thermal desorption