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Microscope Tip (microscope + tip)

Distribution by Scientific Domains
Physics and Astronomy60%

Selected Abstracts

Bottom,Up Fabrication of Carbon-Rich Silicon Carbide Nanowires by Manipulation of Nanometer-Sized Ethanol Menisci,

ADVANCED MATERIALS, Issue 12 2005
M. Tello
A nanometer-sized ethyl alcohol meniscus induced between a conductive atomic force microscope tip and a silicon surface (see Figure) allows the fabrication of nanodots or nanowires of SiCx at a predetermined position on the substrate. The meniscus size and kinetic parameters control the nanostructure size. [source]

Polymer ring formation by electron/hole injection from an STM tip into a C60 close-packed layer

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 13 2006
Ryo Nouchi
Abstract Polymerization and depolymerization of C60 molecules are induced by charge carrier injection from a scanning tunneling microscope tip into C60 close-packed layers. These reactions are hard to be achieved at single molecular precision because of a spatial spread of injected carriers. We report that the carrier-spreading effect produces a ring-shaped distribution of C60 polymers around the carrier injection point. Formation of the polymer ring of C60 is explained by energy dissipation of spreading carriers. Therefore, the polymer ring can be recognized as a direct reflection of carrier propagation. Subsequent electron or hole injections enlarge the ring. This result shows that both electrons and holes can induce both polymerization and depolymerization of C60 molecules. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Phenomenological description of domain recording in ferroelectric semiconductors by using atomic force microscopy

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 10 2005
Anna N. Morozovska
Abstract The equilibrium sizes of domains caused by the electric field of the atomic force microscope tip in ferroelectric semicon-ductor crystals have been calculated. The domain was consi-dered as a prolate semi-ellipsoid with rather thin domain walls. For the first time we modified the Landauer model al-lowing for semiconductor properties of the sample and the surface energy of the domain butt. The free carriers inside the crystal lead to the formation of a screening layer around the domain, which partially shields its interior from the depolari-zation field. The obtained dependence of domain radius on applied voltage is in a good quantitative agreement with the ones of submicron ferroelectric domains recorded by high-voltage atomic force and scanning probe microscopy in LiNbO3, BaTiO3 and RbTiOPO4 crystals. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Mode-Selective Electrical Excitation of a Molecular Rotor

CHEMISTRY - A EUROPEAN JOURNAL, Issue 38 2009
Heather
Batteries not included: The rotation of individual molecular rotors can be driven electrically using electrons from a scanning tunneling microscope tip (see picture). Above the threshold energy of the CH stretch excitation, tunneling electrons are effective at selectively driving rotation, but not translation of the thioether rotors. The ability to rotate individual molecules on command will permit the interrogation of many important effects like rotational energy transfer along 1D molecular chains and rotational orientation switching in ordered arrays. [source]

Current imaging in quantum point contacts

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2006
Alessandro Cresti
Abstract The experimental imaging of microscopic currents in two-dimensional electron gas based systems has been recently realized exploiting an ingenious use of scanning microscope tips. By means of the Keldysh Green's function formalism in a tight-binding framework, I study the electron transport in a model quantum point contact device, obtaining detailed maps of the local current distribution. The results are then compared with those obtained by a direct simulation of the experimental process, i.e. introducing a suitable external potential to reproduce the effect of the coupled microscopic tip on the overall conductance and the electron flow. The analysis of the differences between the two calculations helps to interpret the experimental maps and sheds light on the interference effects of the tip. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]