Exploring the Dual Characteristics of CH3OH Adsorption to Metal Atomic Structures on Si (111)-7 × 7 Surface

Metal atoms were deposited on an Si (111)-7 × 7 surface, and they were adsorbed with alcohol gases (CH3OH/C2H5OH/C3H7OH). Initially, CnH2n+1OH adsorption was simply used as an intermediate layer to prevent the chemical reaction between metal and Si atoms. Through scanning tunneling microscopy (STM) and a mass spectrometer, the CnH2n+1OH dissociation process is further derived as the construction of a surface quasi-potential with horizontal and vertical directions. With the help of three typical metal depositions, the surface characteristics of CH3OH adsorption are more clearly presented in this paper. Adjusting the preheating temperature, the difference of thermal stability between CH3O– and H+ could be obviously derived in Au deposition. After a large amount of H+ was separated, the isolation characteristic of CH3O– was discussed in the case of Fe deposition. In the process of building a new metal-CH3O–-H+ model, the dual characteristics of CH3OH were synthetically verified in Sn deposition. CH3O– adsorption is prone to influencing the interaction between the metal deposition and substrate surface in the vertical direction, while H+ adsorption determines the horizontal behavior of metal atoms. These investigations lead one to believe that, to a certain extent, the formation of regular metal atomic structures on the Si (111)-7 × 7-CH3OH surface is promoted, especially according to the dual characteristics and adsorption models we explored.

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Scanning tunneling microscopy of E. coli RNA polymerase deposited onto an Au substrate by an electrochemical process

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100086192 ◽

1991 ◽

Vol 49 ◽

pp. 378-379

Author(s):

Rebecca W. Keller ◽

Carlos Bustamante ◽

David Bear

Keyword(s):

Scanning Tunneling Microscope ◽

Biological Sample ◽

Substrate Surface ◽

Electrochemical Process ◽

Atomic Resolution ◽

Scanning Tunneling ◽

Tunneling Microscopy ◽

Tunneling Microscope ◽

E Coli ◽

Preparation Techniques

Under ideal conditions, the Scanning Tunneling Microscope (STM) can create atomic resolution images of different kinds of samples. The STM can also be operated in a variety of non-vacuum environments. Because of its potentially high resolution and flexibility of operation, it is now being applied to image biological systems. Several groups have communicated the imaging of double and single stranded DNA.However, reproducibility is still the main problem with most STM results on biological samples. One source of irreproducibility is unreliable sample preparation techniques. Traditional deposition methods used in electron microscopy, such as glow discharge and spreading techniques, do not appear to work with STM. It seems that these techniques do not fix the biological sample strongly enough to the substrate surface. There is now evidence that there are strong forces between the STM tip and the sample and, unless the sample is strongly bound to the surface, it can be swept aside by the tip.

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Templated quasicrystalline ordering of single elements and molecules

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314099185 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C81-C81

Author(s):

H. R. Sharma ◽

J. A. Smerdon ◽

K. Nozawa ◽

K. M. Young ◽

T. P. Yadav ◽

...

Keyword(s):

Substrate Surface ◽

Chemical Properties ◽

Scanning Tunneling ◽

Three Dimension ◽

Tunneling Microscopy ◽

Quantum Size ◽

Adsorption Energies ◽

Molecular Layers ◽

Physical And Chemical ◽

The Impact

We have used quasicrystals as templates for the exploration of new epitaxial phenomena. Several interesting results have been observed in the growth on surfaces of the common Al-based quasicrystals [1]. These include pseudomorphic monolayers, quasiperiodically modulated multilayer structures, and fivefold-twinned islands with magic heights influenced by quantum size effects [1]. Here we present our recent works on the growth of various elements and molecules on a new substrate, icosahedral (i) Ag-In-Yb quasicrystal, which have resulted in various epitaxial phenomena not observed previously. The growth of Pb on the five-fold surface of i-Ag-In-Yb yields a film which possesses quasicrystalline ordering in three-dimension [2]. Using scanning tunneling microscopy (STM) and DFT calculations of adsorption energies, we find that lead atoms occupy the positions of atoms in the rhombic triacontahedral (RTH) cluster, the building block of the substrate, and thus grow in layers with different heights and adsorption energies. The adlayer–adlayer interaction is crucial for stabilizing the epitaxial quasicrystalline structure. We will also present the first example of quasicrystalline molecular layers. Pentacene adsorbs at tenfold-symmetric sites of Yb atoms around surface-bisected RTH clusters, yielding quasicrystalline order [3]. Similarly, C-60 growth on the five-fold surface of i-Al-Cu-Fe at elevated temperature produces quasicrystalline layer, where the growth is mediated by Fe atoms on the substrate surface [3]. The finding of quasicrystalline thin films of single elements and molecules opens an avenue for further investigation of the impact of the aperiodic atomic order over periodic order on the physical and chemical properties of materials.

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Atomistic investigation of surface characteristics and electronic features at high-purity FeSi(110) presenting interfacial metallicity

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2021203118 ◽

2021 ◽

Vol 118 (17) ◽

pp. e2021203118

Author(s):

Biao Yang ◽

Martin Uphoff ◽

Yi-Qi Zhang ◽

Joachim Reichert ◽

Ari Paavo Seitsonen ◽

...

Keyword(s):

Low Temperature ◽

Density Of States ◽

Density Functional ◽

Iron Silicide ◽

Density Functional Theory Calculations ◽

Surface Characteristics ◽

Scanning Tunneling ◽

Magnetic Characteristics ◽

Tunneling Microscopy ◽

Single Crystal Surfaces

Iron silicide (FeSi) is a fascinating material that has attracted extensive research efforts for decades, notably revealing unusual temperature-dependent electronic and magnetic characteristics, as well as a close resemblance to the Kondo insulators whereby a coherent picture of intrinsic properties and underlying physics remains to be fully developed. For a better understanding of this narrow-gap semiconductor, we prepared and examined FeSi(110) single-crystal surfaces of high quality. Combined insights from low-temperature scanning tunneling microscopy and density functional theory calculations (DFT) indicate an unreconstructed surface termination presenting rows of Fe–Si pairs. Using high-resolution tunneling spectroscopy (STS), we identify a distinct asymmetric electronic gap in the sub-10 K regime on defect-free terraces. Moreover, the STS data reveal a residual density of states in the gap regime whereby two in-gap states are recognized. The principal origin of these features is rationalized with the help of the DFT-calculated band structure. The computational modeling of a (110)-oriented slab notably evidences the existence of interfacial intragap bands accounting for a markedly increased density of states around the Fermi level. These findings support and provide further insight into the emergence of surface metallicity in the low-temperature regime.

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Scanning tunneling microscopy study of the early stages of epitaxial growth of CoSi2 and CoSi films on Si(111) substrate: Surface and interface analysis

Thin Solid Films ◽

10.1016/j.tsf.2016.11.006 ◽

2016 ◽

Vol 619 ◽

pp. 153-159 ◽

Cited By ~ 3

Author(s):

V.G. Kotlyar ◽

A.A. Alekseev ◽

D.A. Olyanich ◽

T.V. Utas ◽

A.V. Zotov ◽

...

Keyword(s):

Scanning Tunneling Microscopy ◽

Epitaxial Growth ◽

Substrate Surface ◽

Microscopy Study ◽

Scanning Tunneling ◽

Tunneling Microscopy ◽

Interface Analysis ◽

Surface And Interface ◽

Early Stages ◽

Scanning Tunneling Microscopy Study

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Can Dew Help us to Image Insulating Material?

Microscopy Today ◽

10.1017/s1551929500062234 ◽

1995 ◽

Vol 3 (1) ◽

pp. 18-21

Author(s):

Stephen W. Carmichael

Keyword(s):

High Resolution ◽

Scanning Tunneling Microscopy ◽

Electron Flow ◽

Scanning Tunneling ◽

High Resolution Imaging ◽

Tunneling Microscopy ◽

Insulating Material ◽

Metal Atoms ◽

New Development ◽

Resolution Imaging

In high resolution imaging of biologic structure, atomic lorce microscopy (AFM) has been prevailing over scanning tunneling microscopy (STM). This is primarily because biologic materials do not conduct electricity, and STM requires that electrons flow to or from the surface of the specimen, whereas electron flow is not required for AFM. Microscopists intent on using STM have compensated by coating specimens with a thin coat of metal. However, the presence of metal atoms on the surface degrades the resolution. A new development may make STM more useful to biologists than ever before.

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Ultra High Vacuum Scanning Tunneling Microscopy Observation of Multilayer Step Structure on GaAs and AlAs Vicinal Surface Grown by Metalorganic Vapor Phase Epitaxy

MRS Proceedings ◽

10.1557/proc-448-95 ◽

1996 ◽

Vol 448 ◽

Cited By ~ 3

Author(s):

Jun-Ya Ishizaki ◽

Yasuhiko Ishizaki ◽

Takashi Fukui

Keyword(s):

Scanning Tunneling Microscopy ◽

High Vacuum ◽

Gaas Layer ◽

Layer Growth ◽

Ultra High Vacuum ◽

Scanning Tunneling ◽

Vicinal Surface ◽

Microscopy Observation ◽

Tunneling Microscopy ◽

Atomic Structures

AbstractWe observe the atomic structures at the multilayer step region on MOVPE-grown GaAs (001) vicinal surface using ultra high vacuum scanning tunneling microscopy (UHV-STM), and clarify that (4×2) or (4×3) like reconstruction units are dominant. Oxide free AlAs surfaces grown on GaAs vicinal surface are also successfully observed by UHV-STM. The reconstruction units at the multilayer step region on AlAs surface have the same units on GaAs vicinal surface. GaAs surface has the lack of dimmer rows on the terrace region just below the multilayer step region, while AlAs surface has dimmer rows even on the terrace just below the multilayer step region. GaAs layer growth leads tothe step bunching phenomenon and AlAs surface leads to the step debunching phenomenon.

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