Vibration Compensation for Scanning Tunneling Microscope

The influence of vibration is already one of main obstacles for improving the nano measuring accuracy.The techniques of anti-vibration,vibration isolation and vibration compensation become an important branch in nano measuring field.Starting with the research of sensitivity to vibration of scanning tunneling microscope(STM),the theory,techniques and realization methods of nano vibration sensor based on tunnel effect are initially investigated,followed by developing the experimental devices.The experiments of the vibration detection and vibration compensation are carried out.The experimental results show that vibration sensor based on tunnel effect is characterized by high sensitivity,good frequency characteristic and the same vibratory response characteristic consistent with STM.

BAINITE STRUCTURE IN Cu-Zn-Al ALLOY OBSERVED BY SCANNING TUNNELING MICROSCOPE

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Scanning Tunneling Microscopic and Scanning Tunneling Spectroscopic Studies of Nanocrystalline CdSe Thin Film

Nanocrystalline CdSe thin film prepared by chemical solution deposition was imaged in air with a scanning tunnelling microscope(STM). Scanning tunnelling current spectroscopy(STS) was taken at a fixed tip - sample separation. Tunnelling current(i) - voltage(v) curve and differential conductance spectrum show an n-type schottky rectifying behaviour and yield a direct measure of band gap energy. An increase of bandgap energy (1.8 - 2.1eV) was measured indicating energy quantization of this particular thin film.,

Scanning tunnelling microscope studies of growth of RuO2（110） thin layer on Ru（0001）

This paper reports that the growth of RuO2（110） thin layer growth on Ru（0001） has been investigated by means of scanning tunnelling microscope （STM）. The STM images showed a domain structure with three rotational domains of RuO2（110） rotated by an angle of 120°. The as-grown RuO2（110） thin layer is expanded from the bulk-truncated RuO2（110） due to the large mismatch between RuO2（110） and the Ru（0001） substrate. The results also indicate that growth of RuO2（110） thin layer on the Ru（0001） substrate by oxidation tends first to formation of the Ru-O （oxygen） chains in the [001] direction of RuO2 （110）.

Microscopic growth mechanism and edge states of monolayer 1T'-MoTe_(2)

Transition metal ditellurides(TMTDs)have versatile physical properties,including non-trivial topology,Weyl semimetal states and unique spin texture.Controlled growth of high-quality and large-scale monolayer TMTDs with preferred crystal phases is crucial for their applications.Here,we demonstrate the epitaxial growth of 1T'-MoTe_(2) on Au(111)and graphitized silicon carbide(Gr/SiC)by molecular beam epitaxy(MBE).We investigate the morphology of the grown1T'-MoTe_(2) at the atomic level by scanning tunnelling microscopy(STM)and reveal the corresponding microscopic growth mechanism.It is found that the unique ordered Te structures preferentially deposited on Au(111)regulate the growth of monolayer single crystal 1T'-MoTe_(2),while the Mo clusters were preferentially deposited on the Gr/SiC substrate,which impedes the ordered growth of monolayer MoTe_(2).We confirm that the size of single crystal 1T'-MoTe_(2) grown on Au(111)is nearly two orders of magnitude larger than that on Gr/SiC.By scanning tunnelling spectroscopy(STS),we observe that the STS spectrum of the monolayer 1T'-MoTe_(2) nano-island at the edge is different from that at the interior,which exhibits enhanced conductivity.

Combining scanning tunneling microscope (STM) imaging and local manipulation to probe the high dose oxidation structure of the Si(111)-7×7 surface

Understanding the atomistic formation of oxide layers on semiconductors is important for thin film fabrication,scaling down conventional devices and for the integration of emerging research materials.Here,the initial oxidation of Si(111)is studied using the scanning tunneling microscope.Prior to the complete saturation of the silicon surface with oxygen,we are able to probe the atomic nature of the oxide layer formation.We establish the threshold for local manipulation of inserted oxygen sites to be+3.8 V.Only by combining imaging with local atomic manipulation are we able to determine whether inserted oxygen exists beneath surface-bonded oxygen sites and differentiate between sites that have one and more than one oxygen atom inserted beneath the surface.Prior to the creation of the thin oxide film we observe a flip in the manipulation rates of inserted oxygen sites consistent with more oxygen inserting beneath the silicon surface.

Heisenberg, uncertainty, and the scanning tunneling microscope

We show by a statistical analysis of high-resolution scanning tunneling microscopy （STM） exper- iments, that the interpretation of the density of electron charge as a statistical quantity leads to a conflict with the Heisenberg uncertainty principle. Given the precision in these experiments we find that the uncertainty principle would be violated by close to two orders of magnitude, if this interpretation were correct. We are thus forced to conclude that the density of electron charge is a physically real, i.e., in principle precisely measurable quantity.

Role of Nanocavity Plasmons in Tunneling Electron Induced Light Emission on and near a Molecule

By using a microscopic quantum model,we study theoretically different roles of nanocavity plasmons in scanning tunneling microscope(STM)induced light emission upon selective initial excitation of molecules or plasmons.The time evolution and spectroscopic properties of the emission from the coupled plasmon-molecule system in each case are studied using time-dependent quantum mater equations.When the STM tip is placed on the molecule to ensure direct carrier injection induced molecular excitation,the major role of the plasmons is to enhance the molecular emission via increasing its radiative decay rate,resulting in sharp molecule-speci c emission peaks.On the other hand,when the STM tip is located in close proximity to the edge of the molecule but without direct carrier injection into the molecule,the role of the plasmon-molecule coupling is to cause destructive interferences between the two quantum objects,leading to the occurrence of Fano dips around the energy of the molecular exciton in the plasmonic emission spectra.

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

Au (111 ) 上的铁酞毒和锌酞毒分子的高分辨率的扫描通道显微镜图象用一台扫描通道显微镜(STM ) 的一个 functionalized 尖端被获得了，并且显示出没用干净尖端被观察的富有的 intramolecular 特征。Ab initio 密度功能的理论计算和扩大 H？

Scanning Tunneling Microscope Observations of Non-AB Stacking of Graphene on Ni Films

graphene 的显微镜的特征在化学 transferincluding 以前在 Ni 电影上分离了单层和 bilayers 的原子结构， Moir ? 敷敲映牯敭 ? 祢爠汯楬杮甠? 景琠敨愠湮慥敬 ? 佇 ? 湡 ? 桴 ? 楤浡瑥牥 ? 敷敲洠獯汴 ? 湩琠敨爠湡敧 ???

VARIANT STRUCTURES OF DNA OBSERVED BY SCANNING TUNNELING MICROSCOPE

Deoxyribonucleic acid (DNA), as the essential genetic substance in life process, may undergo structural changes in various environments. For instance, the unwinding of the original double helix of DNA could occur after being heated.

Isolated supramolecules on surfaces studied with scanning tunneling microscopy

To date, supramolecular chemistry is an ever growing research field owing to its crucial role in molecular catalysis, recognition, medicine, data storage and processing as well as artificial photosynthetic devices.Different isolated supramolecules were prepared by molecular self-assembly on surfaces. This review mainly focuses on supramolecular aggregations on noble metal surfaces studied by scanning tunneling microscopy, including dimers, trimers, tetramers, pentamers, wire-like assemblies and Sierpin′ ski triangular fractals. The variety of self-assembled structures reflects the subtle balance between intermolecular and molecule–substrate interactions, which to some extent may be controlled by molecules, substrates and the molecular coverage. The comparative study of different architectures helps identifying the operative mechanisms that lead to the structural motifs. The application of these mechanisms may lead to novel assemblies with tailored physicochemical properties.

Measuring fine molecular structures with luminescence signal from an alternating current scanning tunneling microscope

In scanning tunneling microscopy-induced luminescence(STML),the photon count is measured to reflect single-molecule properties,e.g.,the first molecular excited state.The energy of the first excited state is typically shown by a rise of the photon count as a function of the bias voltage between the tip and the substrate.It remains a challenge to determine the precise rise position of the current due to possible experimental noise.In this work,we propose an alternating current version of STML to resolve the fine structures in the photon count measurement.The measured photon count and the current at the long-time limit show a sinusoidal oscillation.The zero-frequency component of the current shows knee points at the precise voltage as the fraction of the detuning between the molecular gap and the DC component of the bias voltage.We propose to measure the energy level with discontinuity of the first derivative of such a zero-frequency component.The current method will extend the application of STML in terms of measuring molecular properties.

Construction of tunable supramolecular networks studied by scanning tunneling microscopy

In this review we describe a family of organic-based host frameworks which can accommodate guest molecules. The aim of the study is to test the adjustability of this class of mimic structures that may lead to new interesting functions. Emphasis of our research is placed upon four aspects: 1) thermal properties, 2) surface photochemistry, 3) fullerene adsorption, and 4) guest inclusion. It is envisioned that such approach of nanoporous molecular networks might be developed into a new family of useful soft frameworks for studies toward shape-selective catalysis, molecular recognition, self-assembly, and host-guest supramolecular chemistry.

Scanning tunneling microscopic observation of enhanced superconductivity in epitaxial Sn islands grown on SrTiO3 substrate

Recent experimental and theoretical studies of single-layer FeSe film grown on SrTiO_3 have revealed interface enhanced superconductivity, which opens up a pathway to promote the superconducting transition temperature. Here, to investigate the role of SrTiO_3 substrate in epitaxial superconducting film, we grew a conventional superconductor b-Sn(bulk T_c～ 3.72 K) onto SrTiO_3 substrate by molecular beam epitaxy. By employing scanning tunneling microscope and spectroscopic measurements, an enhanced Tcof 8.2 K is found for epitaxial b-Sn islands, deduced by fitting the temperature dependence of the gap values using the BCS formula. The observed interfacial charge injection and enhanced electron–phonon coupling are responsible for this Tcenhancement. Moreover, the critical field of 8.3 T exhibits a tremendous increase due to the suppression of the vortex formation. Therefore, the coexistence of enhanced superconductivity and high critical field of Sn islands demonstrates a feasible and effective route to improve the superconductivity by growing the islands of conventional superconductors on perovskite-type titanium oxide substrates.

The self-assemblies of a newly designed star-shaped molecule end-capped with bromine atoms studied by scanning tunneling microscopy

A new star-shaped molecule StOF-Br_3 containing oligofluorenes and halogen atoms(Bromine) has been synthesized and studied by Scanning Tunneling Microscopy(STM) at the highly oriented pyrolytic graphite(HOPG) surface.We have obtained the high-resolution self-assembled STM images,from which the highly ordered and closely packed non-porous arrangements of the StOF-Br_3 molecular selfassemblies at the heptanoic acid/HOPG surface could be observed.The molecular models and selfassembled StOF-Br_3 architectures have been given in the following text.Besides,we have also figured out the surface free energy by the density functional theory(DFT) calculation,which proved that the halogen...halogen interaction was strong enough to stabilize the ordered molecular self-assemblies.This work verifies the existence of bromine...bromine interactions,and meanwhile provides a kind of effective approach for quickly building ordered molecular nanoarchitectures with large areas and different geometries.

STM钨针尖电化学加工及其装置的改进

本文报导利用自由落体的原理 ,设计了一种新的针尖和液面脱离装置制作了STM钨针尖 ,并与利用步进电机提升针尖的方法进行了比较。分析和实验说明 ,本方法脱离速度较快 ,简单经济 ,效果良好。

Two-dimensional (2D) Supramolecular Coordination at Liquid/ Solid Interfaces Studied by Scanning Tunneling Microscopy

In this review, supramolecular coordination processes on two-dimensional (2D) surfaces or interfaces observed by scanning tunneling microscopy (STM) are discussed. Four parts are mainly involved, which include (1) recognition of Fe^(3+) through functional molecular networks, (2) K^(+)-induced switching of valinomycin, (3) supramolecular coordination happened in a nano-reactor, (4) reversible 2D supramolecular spring driven by coordination. The direct insight of the coordination phenomena provided by STM supplements our knowledge of its mechanism. Since different building blocks can be connected into a whole part through coordination, the understanding of its mechanism will be beneficial to the future design of molecular devices.

Bis(phthalocyaninato)yttrium Grown on Au(111): Electronic Structure of a Single Molecule and the Stability of Two- dimensional Films Investigated by Scanning Tunneling Microscopy/Spectroscopy at 4.8 K

Scanning tunneling microscopy/spectroscopy(STM/STS)at 4.8 K has been used to examine the growth of a double-decker bis(phthalocyaninato)yttrium(YP_(c2))molecule on a reconstructed Au(111)substrate.Local differential conductance spectra(dI/dV)of a single YPc2 molecule allow the characteristics of the highest occupied molecular orbital(HOMO)and the lowest unoccupied molecular orbital(LUMO)to be identified.Furthermore,lateral distributions of the local density of states(LDOS)have also been obtained by dI/dV mapping and confirmed by first principles simulations.These electronic feature mappings and theoretical calculations provide a basis for understanding the unique STM morphology of YPc2,which is usually imaged as an eight-lobed structure.In addition,we demonstrate that bias-dependent STM morphologies and simultaneous dI/dV maps can provide a way of understanding the stability of two-dimensional YP_(c2) films.