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Anisotropic monolayer of ReX_(2)on Au foils for exploring abnormal growth behavior and electronic properties

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Nano Research 2023年第3期16卷 4197-4210页

作者： Wenzhi Quan Shuangyuan Pan Fan Zhou Yanfeng Zhang Academy for Advanced Interdisciplinary Studies Peking UniversityBeijing 100871China School of Materials Science and Engineering Peking UniversityBeijing 100871China

As an emerging class of semiconducting transition metal dichalcogenides(TMDCs),two-dimensional(2D)rhenium dichalcogenides(ReX_(2),X=S or Se)have recently aroused great research interest due to their unique anisotropic structure(1T′phase),and the related novel properties and applications.Recently,many efforts have been devoted to the controllable syntheses of high-quality monolayer or few-layer ReX_(2)flakes/films by chemical vapor deposition(CVD),wherein the metallic Au foil is found to be a unique substrate,due to the relatively strong interfacial coupling between monolayer ReX_(2)and Au.And the conductive nature of Au enables in situ characterizations of the as-grown ReX_(2)samples,which is essential for exploring the fundamental properties and internal growth mechanisms.Hereby,this review focuses on the recent progresses on the CVD syntheses and in situ characterizations of high-quality monolayer ReX_(2)flakes/films and their heterostructures with graphene on Au foils.The effects of Au foils on improving the crystal quality and inducing the growth of monolayer ReX_(2)single crystals are intensively addressed.The crystallinity,domain morphology,atomic and electronic structures,as well as the growth behaviors of monolayer ReX_(2)flakes/films and graphene/ReX_(2)heterostructures on Au revealed by in situ characterization techniques are also highlighted.As contrasts,the growth behaviors of monolayer or few-layer ReX_(2)on insulating substrates are also discussed.Besides,the potential applications of 2D ReX_(2)in new-generation electronic,optoelectronic devices,and energy-related fields are also introduced.Finally,future research directions are also prospected for propelling the practical applications of 2D ReX_(2)materials in more versatile fields.

关键词： rhenium dichalcogenides(ReX_(2)) Au chemical vapor deposition scanning tunneling microscopy/spectroscopy growth behavior electronic properties

electronic properties of graphene nanoribbon doped by boron/nitrogen pair:a first-principles study

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Chinese Physics B 2012年第2期21卷 450-456页

作者：肖金杨志雄谢伟涛肖立新徐慧欧阳方平 School of Physics Science and Technology Central South UniversityChangsha 410083China School of Physics and State Key Laboratory for Artificial Microstructure and Mesoscopic Physics Peking UniversityBeijing 100871China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China

By using the first-principles calculations, the electronic properties of graphene nanoribbon （GNR） doped by boron/nitrogen （B/N） bonded pair are investigated. It is found that B/N bonded pair tends to be doped at the edges of GNR and B/N pair doping in GNR is easier to carry out than single B doping and unbonded B/N co-doping in GNR. The electronic structure of GNR doped by B/N pair is very sensitive to doping site besides the ribbon width and chirality. Moreover, B/N pair doping can selectively adjust the energy gap of armchair GNR and can induce the semimetal-semiconductor transmission for zigzag GNR. This fact may lead to a possible method for energy band engineering of GNRs and benefit the design of graphene electronic device.

关键词： graphene nanoribbons boron/nitrogen pairs doping electronic properties firstprinciples

electronic properties of hydrogen- and oxygen-terminated diamond surfaces exposed to the air

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Chinese Physics B 2009年第5期18卷 2041-2047页

作者：刘峰斌汪家道陈大融颜大运 State Key Laboratory of Tribology Tsinghua University

The electronic properties of hydrogen- and oxygen-terminated diamond surfaces exposed to the air are investigated by scanning probe microscopy （SPM）. The results indicate that for the hydrogen-terminated diamond surface a shallow acceptor above the valence-band-maximum （VBM） appears in the band gap. However, the oxygen-terminated diamond film exhibits a high resistivity with a wide band gap. Based on the density-functional-theory, the densities of states, corresponding to molecular adsorbate in hydrogenated and oxygenated diamond （100） surfaces, are studied. The results show that the shallow acceptor in the band gap for the hydrogen-terminated diamond film can be attributed to the interaction between the surface C H bonding orbitals and the adsorbate molecules, while for the oxygen-terminated diamond film, the interaction between the surface C-O bonding orbitals and the adsorbate molecules can induce occupied states in the valence-band.

关键词： hydrogen-termination oxygen-termination electronic properties diamond film

electronic properties of one-dimensional systems with long-range correlated binary potentials

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Chinese Physics B 2011年第8期20卷 335-339页

作者： Gong Long-Yan Tong Pei-Qing Zhou Zi-Cong College of Science Nanjing University of Posts and Telecommunications Nanjing 210003 China Department of Physics Nanjing Normal University Nanjing 210097 China Department of Physics Tamkang University 151 Ying-Chuan Tamsui 25137 Taipei Taiwan China

We study numerically the electronic properties of one-dimensional systems with long-range correlated binary potentials. The potentials are mapped from binary sequences with a power-law power spectrum over the entire frequency range, which is characterized by correlation exponent β. We find the localization length ζ increases withβ. At system sizes N →∞, there are no extended states. However, there exists a transition at a threshold ζ. Whenβ 〉 βc, we obtain ζ 〉 0. On the other hand, at finite system sizes, ζ≥ N may happen at certain β, which makes the system ＂metallic＂, and the upper-bound system size N＊（β） is given.

关键词： electronic properties long-range correlation binary potentials localization

electronic properties of Nanocrystalline-Si Embedded in Asymmetric Ultrathin SiO2 by In-Situ Fabrication Technique

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Chinese Physics Letters 2005年第3期22卷 733-736页

作者：吴良才陈坤基余林蔚戴敏马忠元韩培高李伟黄信凡 NationalLaboratoryofSolidStateMicrostructuresandDepartmentofPhysics NanjingUniversityNanjing210093

Structures of nanocrystalline-Si (nc-Si) sandwiched between two asymmetric ultrathin SiO2 layers were fabricated. The nc-Si (dot density of 1011cm−2) was formed by decomposition of hydrogen-diluted silane and the ultrathin SiO2 layers (about 2nm) were prepared by plasma oxidation at a lower temperature (250 degrees C). The whole fabrication processes were completed in situ in a plasma-enhanced chemical vapour deposition system. By using the capacitance–voltage (C–V) and conductance–voltage (G–V) spectroscopy, we studied the electronic properties of the annealed samples. The experimental results show that there are distinct capacitance peaks and conductance plateau or peaks for annealed samples at room temperature, which can be explained by direct tunnelling of electrons into the nc-Si. At the same time, Coulomb blockade plays an important role in the electronic transport in the nc-Si. The effect of thermal annealing in N2 ambient on the electronic properties was studied and the results indicate that high temperature (1000 degrees C) annealing can improve the size uniformity of the nc-Si prepared by decomposition of hydrogen-diluted silane.

关键词： electronic properties Nanocrystalline-Si Embedded Asymmetric Ultrathin SiO_2 In-Situ Fabrication Technique

Single-cluster electronics using metallic clusters:Fabrications,regulations,and applications

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Nano Research 2024年第1期17卷 65-78页

作者： Caiyun Wei Wei Xu Shurui Ji Ruiyun Huang Junyang Liu Wenqiu Su Jie Bai Jiale Huang Wenjing Hong State Key Laboratory of Physical Chemistry of Solid Surfaces National Engineering Research Centre of Chemicals for Electronic ManufacturingCollege of Chemistry and Chemical Engineering&Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM)Xiamen UniversityXiamen 361005China

Metallic clusters,ranging from 1 to 2 nm in size,have emerged as promising candidates for creating nanoelectronic devices at the single-cluster level.With the intermediate quantum properties between metals and semiconductors,these metallic clusters offer an alternative pathway to silicon-based electronics and organic molecules for miniaturized electronics with dimensions below 5 nm.Significant progress has been made in studies of single-cluster electronic devices.However,a clear guide for selecting,synthesizing,and fabricating functional single-cluster electronic devices is still required.This review article provides a comprehensive overview of single-cluster electronic devices,including the mechanisms of electron transport,the fabrication of devices,and the regulations of electron transport properties.Furthermore,we discuss the challenges and future directions for single-cluster electronic devices and their potential applications.

关键词： single-cluster junctions electronic properties electron transport metallic clusters structure regulation

DFT investigation of half-metallic ferromagnetic rare earth based spinels MgHo_(2)Z_(4)(Z=S,Se)

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Journal of Rare Earths 2024年第1期42卷 121-128,I0005页

作者： Maiza Zanib Mumtaz Manzoor N.A.Noor M.Waqas Iqbal Mazia Asghar H.H.Hegazy A.Laref Department of Physics Riphah International UniversityLahore CampusPakistan Research Centre for Advanced Materials Science King Khalid UniversityP.O.Box 9004AbhaSaudi Arabia Department of Physics Faculty of ScienceKing Khalid UniversityP.O.Box 9004AbhaSaudi Arabia Department of Physics and Astronomy College of ScienceKing Saud UniversityRiyadh11451Saudi Arabia

Half-metallic ferromagnetism,mechanical as well as thermoelectric properties for rare earth-based spinels MgHo_(2)Z_(4)(Z=S,Se)were investigated using density functional theory(DFT).Structural optimization was done with Perdew-Burke-Ehrenzorf(PBE)sol-generalized gradient approximation(GGA)to calculate the lattice constant of both spinels comparable to experimental data.In addition,Born stability criteria and negative formation energy show that our studied spinels are also structurally and dynamically stable in the cubic phase.For ferromagnetic(FM)state stability,we also calculated the energy differences among FM,antiferromagnetic(AFM),and non-magnetic(NM)states.Additionally,Curie temperatures of ferromagnetic phases were also estimated.We used Trans-Blaha improved BeckeJohnson(TB-mBJ)potential functional for electronics as well as magnetic characteristics,which lead to the consistent explanation of half-metallic ferromagnetism,representing the whole band-occupancy in material with exact detail of density of states(DOS).The stable FM state was examined in spinels due to the exchange splitting of Ho cation consisting of p-d hybridizations compatible with the result achieved for electronics band structure and DOS.Further,spin magnetic moment was explained in terms of anion,cation,and sharing charge on studied spinels.In addition,the calculated thermoelectric properties clearly show that operation range of these systems may be utilized by future experimental works for identifying the potential applications of these systems.

关键词： Ho-based spinels DFT simulations Mechanical parameters electronic properties HM ferromagnetism Figure of merit

electronic structures and transport properties of BN nanodot superlattices of armchair graphene nanoribbons

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Journal of Semiconductors 2011年第9期32卷 6-11页

作者：安丽萍刘念华 Institute for Advanced Study Nanchang University Department of Physics Yanshan University

The electronic and transport properties of embedded boron nitride（BN） nanodot superlattices of armchair graphene nanoribbons are studied by first-principles calculations.The band structure of the graphene superlattice strongly depends on the geometric shape and size of the BN nanodot,as well as the concentration of nanodots.The conduction bands and valence bands near the Fermi level are nearly symmetric,which is induced by electron-hole symmetry.When B and N atoms in the graphene superlattices with a triangular BN nanodot are exchanged,the valance bands and conduction bands are inverted with respect to the Fermi level due to electron-hole symmetry.In addition,the hybridization ofπorbitals from C and redundant B atoms or N atoms leads to a localized band appearing near the Fermi level.Our results also show a series of resonant peaks appearing in the conductance.This strongly depends on the distance of the two BN nanodots and on the shape of the BN nanodot. Controlling these parameters might allow the modulation of the electronic response of the systems.

关键词： graphene nanoribbon BN nanodot electronic properties transport properties

Effect of structural vacancies on lattice vibration,mechanical,electronic,and thermodynamic properties of Cr5BSi3

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Chinese Physics B 2022年第2期31卷 496-502页

作者：董天慧张旭东杨林梅王峰 School of Science Shenyang University of TechnologyShenyang 110870China School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China

In recent years,transition metal silicides have become the potential high temperature materials.The ternary silicide has attracted the attention of scientists and researchers.But their inherent brittle behaviors hinder their wide applications.In this work,we use the first-principles method to design four vacancy defects and discuss the effects of vacancy defects on the structural stability,mechanical properties,electronic and thermodynamic properties of hexagonal Cr;BSi;silicide.The data of lattice vibration and thermodynamic parameters indicate that the Cr;BSi;with different atomic vacancies can possess the structural stabilities.The different atomic vacancies change the mechanical properties and induce the Cr;BSi;to implement the brittle-to-ductile transition.The shear deformation resistance and volume deformation resistance of Cr;BSi;are weakened by different vacancy defects.But the brittleness behavior is remarkably improved.The structural stability and brittle-to-ductile transition of Cr;BSi;with different vacancies are explored by the electronic structures.Moreover,the thermal parameters indicate that the Cr;BSi;with vacancies exhibit different thermodynamic properties with temperature rising.

关键词： vacancies in Cr5BSi3 brittle-to-ductile transition electronic properties thermodynamic properties