A5002313708- Force Microscopy Techniques and Applications
- Adhesion, Friction, and Surface Interactions
- Diamond and Carbon-based Materials Research
- Molecular Junctions and Nanostructures
- Semiconductor materials and devices
- Advanced Surface Polishing Techniques
- GaN-based semiconductor devices and materials
- Polymer Nanocomposite Synthesis and Irradiation
- Electron and X-Ray Spectroscopy Techniques
- Surface Roughness and Optical Measurements
- Lubricants and Their Additives
- Advanced Materials Characterization Techniques
- Analytical Chemistry and Sensors
- Surface and Thin Film Phenomena
University of Pittsburgh
2017-2025
The adhesion of nanoparticles to their supports is key performance and stability. However, scientific advances in this area have been hampered by the difficulty experimentally probing adhesion. To date, only a single technique has developed that can directly measure nanoparticle adhesion, inherently limited monometallic systems. We present versatile for direct measurement bimetallic This combines spatial resolution transmission electron microscopy with force an atomic microscope probe...
The adhesion between nanoscale components has been shown to increase with applied load, contradicting well-established mechanics models. Here, we use in situ transmission electron microscopy and atomistic simulations reveal the underlying mechanism for this as a change mode of separation. Analyzing 135 tests on technologically relevant materials anatase TiO2, silicon, diamond, demonstrate transition from fracture-controlled strength-controlled When fracture models are incorrectly applied,...
Conductive modes of atomic force microscopy are widely used to characterize the electronic properties materials, and in such measurements, contact size is typically determined from current flow. Conversely, nanodevice applications, flow predicted estimated size. In both cases, it very common relate using well-established ballistic electron transport theory. Here we performed 19 electromechanical tests platinum nanocontacts with situ transmission measure conductance. We also molecular...
Metal nanocontacts play a critical role in atomic force microscopy, functional nanostructures, metallic nanoparticles, and nanoscale electromechanical devices. In all cases, knowledge of the area contact, its variation with load, is for quantitative prediction behavior. Often, contact predicted using continuum mechanics models which relate size to geometry, material properties, load. Here we show platinum nanoprobes that deviates significantly from these predictions, even at low applied...
Multi-scale surface topography is critical to function, yet the very smallest scales are not accessible with conventional measurement techniques.Here we demonstrate two separate approaches for measuring small-scale in a transmission electron microscope (TEM).The first technique harnesses "conventional" methods preparation of TEM cross-section, and presents how these may be modified ensure preservation original surface.The second involves deposition material interest on pre-fabricated...
Atomistic simulations provide an approach to correcting the error in contact-area measurements from conductive atomic force microscopy for platinum with a thin insulating layer.
Continuum mechanics models for contacting surfaces assume a constant interfacial energy, or work of adhesion, between materials. Recent studies have challenged this assumption, instead demonstrating that stress-dependent chemical reactions across the interface modify adhesion. Here, we perform 77 adhesion tests on diamond–silicon contacts using in situ transmission electron microscopy and atomistic simulations to quantify how changes as function applied pressure. The results show sevenfold...
Journal Article In situ Mechanical Testing of Contacts Between Nanoscale Bodies: Measuring the Load-dependence Contact Area. Get access Sai Bharadwaj Vishnubhotla, Vishnubhotla Engineering and Materials Science, University Pittsburgh, PA, USA Search for other works by this author on: Oxford Academic Google Scholar Rimei Chen, Chen School Engineering, California-Merced, Merced, CA, Subarna R Khanal, Khanal Xiaoli Hu, Hu Ashlie Martini, Martini Tevis D B Jacobs Microscopy Microanalysis, Volume...
Fundamental understanding of the mechanics contact for metallic nanocontacts is crucial scanning probe microscopy (SPM) techniques that enable precise measurements electrical properties surfaces. The conventional approach quantitative analysis SPM relies on combining continuum models with classical or ballistic electronic transport theories to understand current flow through nanocontact. To investigate robustness this approach, in situ testing was conducted a platinum/platinum nanocontact...