Nanomechanics Using an Ultra-Small Amplitude AFM

2000 ◽  
Vol 649 ◽  
Author(s):  
Peter M. Hoffmann ◽  
Steve Jeffery ◽  
Ahmet Oral ◽  
Ralph A. Grimble ◽  
H. özgür Özer ◽  
...  
Keyword(s):  
Mechanical Response ◽  
High Vacuum ◽  
Interaction Force ◽  
Ultra High Vacuum ◽  
Atomic Scale ◽  
Resonance Amplitude ◽  
Molecular Ordering ◽  
Atomic Relaxation ◽  
New Type ◽  
Sample Separation

ABSTRACTA new type of AFM is presented which allows for direct measurements of nanomechanical properties in ultra-high vacuum and liquid environments. The AFM is also capable of atomic-scale imaging of force gradients. This is achieved by vibrating a stiff lever at very small amplitudes of less than 1 Å (peak-to-peak) at a sub-resonance amplitude. This linearizes the measurement and makes the interpretation of the data straight-forward. At the atomic scale, interaction force gradients are measured which are consistent with the observation of single atomic bonds. Also, atomic scale damping is observed which rapidly rises with the tip-sample separation. A mechanism is proposed to explain this damping in terms of atomic relaxation in the tip. We also present recent results in water where we were able to measure the mechanical response due to the molecular ordering of water close to an atomically flat surface.

Linear measurements of nanomechanical phenomena using small-amplitude AFM

2004 ◽  
Vol 838 ◽  
Author(s):  
Peter M. Hoffmann ◽  
Shivprasad Patil ◽  
George Matei ◽  
Atay Tanulku ◽  
Ralph Grimble ◽  
...  
Keyword(s):  
High Vacuum ◽  
Data Interpretation ◽  
Ultra High Vacuum ◽  
Atomic Scale ◽  
Single Atom ◽  
Linear Measurements ◽  
Interaction Range ◽  
Force Microscopy ◽  
Atomic Force ◽  
Molecular Ordering

ABSTRACTDynamic Atomic Force Microscopy (AFM) is typically performed at amplitudes that are quite large compared to the measured interaction range. This complicates the data interpretation as measurements become highly non-linear. A new dynamic AFM technique in which ultra-small amplitudes are used (as low as 0.15 Angstrom) is able to linearize measurements of nanomechanical phenomena in ultra-high vacuum (UHV) and in liquids. Using this new technique we have measured single atom bonding, atomic-scale dissipation and molecular ordering in liquid layers, including water.

Atomic-scale friction on diamond(111) studied by ultra-high vacuum atomic force microscopy

1997 ◽  
Vol 384 (1-3) ◽  
pp. L828-L835 ◽  
Author(s):  
R.J.A. van den Oetelaar ◽  
C.F.J. Flipse
Keyword(s):  
Atomic Force Microscopy ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Atomic Scale ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals Subnanophase coatings as new type low-dimensional nanomaterials: ultra-high-vacuum synthesis, properties and application

2019 ◽  
Vol 2 (2) ◽  
Author(s):  
Nikolay Inokent’evich Pliusnin
Keyword(s):  
High Vacuum ◽  
Ultra High Vacuum ◽  
Wetting Layer ◽  
New Approach ◽  
Synthesis Properties ◽  
Physical Deposition ◽  
New Type ◽  
Low Dimensional ◽  
Application Prospects

A classification of low-dimensional nanomaterials is given, and a new type of these nanomaterials – subnanophase coatings is proposed. Experimental results on the formation of a wetting layer of a transition metal on a silicon substrate by physical deposition in vacuum and results of this layer identification by the EELS method are given. Based on these results, a new approach to the formation of subnanophase coatings has been proposed by creation of a interface stresses which structuring WL. The possible properties and application prospects of subnanophase coatings are considered.

Chemically Clean Planar Interface Synthesis: Substrate Surface and Interface Cross Section Microscopy

1997 ◽  
Vol 3 (S2) ◽  
pp. 635-636
Author(s):  
J. Xu ◽  
M.J Cox ◽  
M.J. Kim
Keyword(s):  
Ion Beam ◽  
Substrate Surface ◽  
High Vacuum ◽  
Auger Spectroscopy ◽  
Planar Interface ◽  
Ultra High Vacuum ◽  
Atomic Scale ◽  
Boundary Structure ◽  
Surface And Interface ◽  
Interface Synthesis

An ultra high vacuum (UHV) planar interface unit has been constructed to study the effect of interface/boundary structure and chemistry on properties. We report here initial observations of substrate morphology and chemistry prior to bonding and resulting interface morphology obtained using austenitic stainless steel.To synthesize chemically clean planar interfaces by diffusion bonding, the substrate must be macroscopically and microscopically flat and chemically clean. Macro-flatness, necessary for bonding to occur over large areas, was ensured by conventional mechanical polishing and lapping. Substrate surfaces were cleaned by a broad (3cm) 500 eV ion beam (Ar or Xe) at 15° incidence. The resulting changes in substrate near-atomic-scale roughness and chemistry were analyzed using Auger spectroscopy (AES) and Atomic Force Microscopy (AFM). Before ion beam cleaning, the sub-strates exhibited high oxygen and carbon contamination (Fig la). Both Xe and Ar ion cleaning reduced these values; the result for 5 minutes Ar cleaning is shown in Fig lb.

Collaborating on the Design and Manufacture of an Atomic Artifact Transport System: A Case Study in VRML As a Visualization Tool for Consensus Building

1998 ◽  
Author(s):  
R. H. Allen ◽  
S. Nidamarthi ◽  
P. V. M. Rao ◽  
R. Rhorer ◽  
R. D. Sriram ◽  
...  
Keyword(s):  
Transport System ◽  
High Vacuum ◽  
Project Team ◽  
Ultra High Vacuum ◽  
Atomic Scale ◽  
Team Members ◽  
Face To Face ◽  
Engineering Models ◽  
Platform Independence ◽  
Design And Manufacture

Abstract We report on our experience using the Virtual Reality Markup Language (VRML) to collaborate on the design and manufacture of an artifact transport system (ATS). Specifically designed for the purpose of transporting nanometer-scale dimensional artifacts at pressures ∼10−8 Pa, the ATS consists of a transport cart and an ultra-high vacuum (UHV) system. As its name implies, the ATS is to transport an atomically-accurate specimen created in a molecular beam epitaxy (MBE) laboratory to a scanning tunnel microscope (STM) laboratory across the NIST campus, where metrologists verify atomic-scale measurements. The project team involved between 15 and 20 participants — designers, engineers, physicists and manufacturers — and each individual was involved with the design and assembly of the ATS to varying degrees. After the project engineers developed their assembly models with their CAD tools, we exported the components and assemblies to VRML files. These representations were made available, via web browsers with VRML viewers, for feedback to project team members on their own workstations, which included PCs, Macintoshes and Suns. The port involved characterizing the simulation’s performance over a range of parameters such as processor capability, file size, VRAM available and graphics card capability. After meeting with the fabricators and physicists to determine the approximate assembly sequence of the ATS, we edited, augmented and animated the VRML files on a high-end workstation. By visualizing the animation sequence in a common facility with a videowall, participants were able to reach a consensus for the design and assembly changes needed. We conclude that VRML did help our team collaborate in the design and fabrication processes, although the technology supplemented, rather that supplanted face-to-face meetings. Our experience with VRML on multiple workstations leads us also to conclude that the language needs to be characterized to enhance easy development of engineering models and to achieve true and complete platform-independence.

Inspection and Manipulation of Ferroelectrics on the Nanometer Scale

1999 ◽  
Vol 574 ◽  
Author(s):  
L. M. Eng
Keyword(s):  
Domain Walls ◽  
Near Field ◽  
High Vacuum ◽  
Polarization Vector ◽  
Optical Microscope ◽  
Ferroelectric Materials ◽  
Ultra High Vacuum ◽  
Atomic Scale ◽  
Dynamic Force ◽  
Force Microscopy

AbstractThe increasing interest in scanning probe instruments (SPM) stems from the outstanding possibilities in measuring electric, magnetic, optical, and structural properties of surfaces and surface layers down to the molecular and atomic scale. For the inspection of ferroelectric materials both the scanning force microscope (SFM) and the scanning near-field optical microscope (SNOM) are promising techniques revealing information on the polarization vector and the electric field induced stress within a crystal. Polarization sensitive modes are discussed as is friction force microscopy, dynamic force microscopy (DFM) and voltage modulated SFM. From these measurements, 180° domain walls (c-domains) are resolved down to 4 nm, while 3-dimensional polarization mapping in ferroelectric BaTiO3 ceramics reveals a 25 nm resolution. On the other hand, non-contact DFM measurements in ultra-high vacuum are able to resolve ferroelectric surfaces down to the atomic scale. Then also the chemical heterogeneity at the sample surface is differentiated from ferroelectric domains down to a 5 nm lateral resolution, taking advantage of the short range chemical forces. SNOM in contrast probes the optical properties of ferroelectric crystals both in transmission and reflection. Here image contrast arises from changes in the refractive index between different domains as well as at domain walls. In addition, SPM instruments are used for the local modification of ferroic samples by applying a relatively high voltage pulse to the SPM tip. Domains with diameters down to 30 nm are thus created with the size depending on both the switching and material parameters.

Intrinsic Point Defects on a TiO2(110) Surface and Their Reaction with Oxygen: A Scanning Tunneling Microscopy Study

1997 ◽  
Vol 474 ◽  
Author(s):  
Markus Kuhn ◽  
J. F. Anderson ◽  
Jeremy Lehman ◽  
Talib Mahmoud ◽  
Ulrike Diebold
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Molecular Oxygen ◽  
Point Defects ◽  
Healing Process ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Defect Sites

ABSTRACTThe interaction of molecular oxygen, at room temperature, with a reduced TiO2(110) surface has been studied in situ by scanning tunneling microscopy (STM). Oxygen vacancies (point defects) were created on a clean TiO2(110) surface by annealing in ultra-high vacuum and successfully imaged on the atomic scale. These point defect sites were stable under ultrahigh vacuum conditions. During exposure to molecular oxygen, new point defects appear at different locations on the surface although their overall number is reduced. A mechanism for this dynamic healing process is proposed.

Theoretical and Experimental Evidences of Sequential Phase Formation during Sub-Nanometric-Thick Film Reactive Diffusion

2011 ◽  
Vol 172-174 ◽  
pp. 633-639
Author(s):  
Alain Portavoce ◽  
Guy Tréglia ◽  
Boubekeur Lalmi ◽  
Christophe Girardeaux ◽  
Dominique Mangelinck ◽  
...  
Keyword(s):  
Thick Film ◽  
Phase Formation ◽  
Kinetic Monte Carlo ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Atomic Scale ◽  
Reactive Diffusion ◽  
Kinetic Monte Carlo Simulations ◽  
Sequential Phase ◽  
Sequential Formation

Silicide sequential phase formation during tens-of-nanometer-thick metallic film reaction on Si substrate has been extensively studied. Nevertheless, the reasons of sequential phase formation are still under debate, and have been poorly studied at the atomic scale. Using atomistic kinetic Monte Carlo simulations, we show that considering a binary fcc non-regular solid solution, without diffusion asymmetries, the diffusive reaction of a sub-nanometer-thick film (~5 atomic monolayers) on a semi-infinite substrate leads to the sequential formation of all the phases present in the binary phase diagram, starting with the film atom richest phase. These predictions are supported by experimental observations: the dissolution of a 4 monolayer-thick Si film on a Ni(111) substrate, duringin-situultra high vacuum Auger electron spectroscopy, shows delays and kinetic changes in the dissolution process that may correspond to the sequential formation of the Ni-Si compounds, i.e. NiSi2, NiSi, Ni3Si2, Ni2Si, Ni31Si12and Ni3Si.

scholarly journals Near Contact Mode AFM: Overcoming Surface Fluid Layer In Air And Achieve Ultra-High Resolution

1998 ◽  
Vol 6 (8) ◽  
pp. 12-15
Author(s):  
Huddee J. Ho
Keyword(s):  
Surface Defects ◽  
Fluid Layer ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Atomic Scale ◽  
Major Goal ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Scale Surface

A major goal of Atomic Force Microscopy (AFM) is to achieve nanometer resolution on surface topography, Vibrating cantilever mode (VCM) is an important configuration of an AFU instrument, It was proposed in the first AFM paper.VCM in ultra-high vacuum (UHV) results in true AFM atomic resolution, which reveals atomic scale surface defects such as a single missing atom in a lattice. However, the VCM operation in air has many difficulties due to the surface contamination on the sample and the AFM tip. The most popular operation modes of the VCM are the non-contact mode and the Tapping mode. Both of these have limited lateral resolution in air.

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