Andriy Moskalenko

Cryomechanically obtained nanocrystalline titanium: microstructure and mechanical properties

Using a cryomechanical treatment method (an alternative method of intense plastic deformation), nanocrystalline bulk titanium of technical-grade purity with average grain-size up to 35nm has been obtained for the first time. The method is based on the authors’ previous investigations of the role of twinning in the low-temperature plasticity of titanium. Transmission electron microscopy is used to determine the size of the regions of coherent scattering (grains-crystallites); a semiquantitative estimate is made of their dispersity as a function of their mechanothermal treatment regimes. The influence of the average grain size in the nanometer range on the mechanical properties of titanium is studied.

Nanomechanical electron shuttle consisting of a gold nanoparticle embedded within the gap between two gold electrodes

Nanomechanical shuttles transferring small groups of electrons or even individual electrons from one electrode to another offer a novel approach to the problem of controlled charge transport. Here, we report the fabrication of shuttle-junctions consisting of a 20 nm diameter gold nanoparticle embedded within the gap between two gold electrodes. The nanoparticle is attached to the electrodes through a monolayer of flexible organic molecules which play the role of springs so that when a sufficient voltage bias is applied, then nanoparticle starts to oscillate transferring electrons from one electrode to the other. Current-voltage characteristics for the fabricated devices have been measured and compared with the results of our computer simulations.

An atomic force microscope nanoscalpel for nanolithography and biological applications

We present the fabrication of specialized nanotools, termed nanoscalpels, and their application for nanolithography and nanomechanical manipulation of biological objects. Fabricated nanoscalpels have the shape of a thin blade with the controlled thickness of 20-30 nm and width of 100-200 nm. They were fabricated using electron beam induced deposition at the apex of atomic force microscope probes and are hard enough for a single cut to penetrate a approximately 45 nm thick gold layer; and thus can be used for making narrow electrode gaps required for fabrication of nanoelectronic devices. As an atomic force microscope-based technique the nanoscalpel provides simultaneous control of the applied cutting force and the depth of the cut. Using mammalian cells as an example, we demonstrated their ability to make narrow incisions and measurements of local elastic and inelastic characteristics of a cell, making nanoscalpels also useful as a nanosurgical tool in cell biology. Therefore, we believe that the nanoscalpel could serve as an important tool for nanofabrication and nanosurgery on biological objects.

Photoexcited silicon nanocrystals as multifunctional spin-flip activator

Nano-sized silicon crystals have entirely new physical properties which do not occur in its bulk form. Investigation of its photoluminescence properties can explain the mechanism of transferring energy from photoexcited excitons confined in silicon nanocrystals to energy accepting substances via electron exchange mechanism, This excitation process changes the electronic spin structure of the acceptor molecule, which is forbidden in the dipole approximation, and therefore it requires the involvement of photosensitizers.