V. A. Seleznev

Free-standing and overgrown InGaAs/GaAs nanotubes, nanohelices and their arrays

Abstract The possibility is shown to fabricate a wide class of free-standing nano-objects based on few monolayers thick scrolled heterostructures. Using an ultra-thin film (1 ML GaAs:1 ML InAs), nanotubes with an inside diameter of ≈2 nm have been obtained, which constitutes the limiting size for this system. Molecular-beam-expitaxy overgrown structures with nanotubes embedded into GaAs have been obtained.

Semiconductor micro- and nanoneedles for microinjections and ink-jet printing

For the first time, semiconductor Micro- and nanoneedles for microinjections into living cell and ink-jet printing have been fabricated. In the fabrication process, novel methods permitting directional rolling of lithographically predefined strained heterofilms into tubes and preparation of tubes protruding over substrate edges (needles) are employed. The fabricated InGaAs/GaAs and Si/GeSi needles are shown to be mechanically strong enough to allow multiple punching of thick-walled plant cells. The proposed technique is compatible with the integrated-circuit technology and can be applied to many types of strained heterostructures.

Nanoscale engineering using controllable formation of ultra-thin cracks in heterostructures

Abstract A new technique for fabrication of nano- and atomic- scale device elements and quantum systems which cannot be obtained by any other technology is proposed. The technique is based an experimentally established possibility to create atomically sharp-edged cracks of a desired length and direction in a given layer of heterostructure. Ultra-narrow (1 nm) and perfectly straight windows-slits in the GaAs layer-mask of semiconductor structures and atomicaly sharp -edged windows of a complicated form have been fabricfted for the fist time. It was shown, that the width of a window-slit can be varied with high precision needed for a self-alignment fabrication technology. New maskless techniques for fabricating nanoscale elements are described.

3D heterostructures and systems for novel MEMS/NEMS

In this review, we consider the application of solid micro- and nanostructures of various shapes as building blocks for micro-electro-mechanical or nano-electro-mechanical systems (MEMS/NEMS). We provide examples of practical applications of structures created by MEMS/NEMS fabrication. Novel devices are briefly described, such as a high-power electrostatic nanoactuator, a fast-response tubular anemometer for measuring gas and liquid flows, a nanoprinter, a nanosyringe and optical MEMS/NEMS. The prospects are described for achieving NEMS with tunable quantum properties.Abstract In this review, we consider the application of solid micro- and nanostructures of various shapes as building blocks for micro-electro-mechanical or nano-electro-mechanical systems (MEMS/NEMS). We provide examples of practical applications of structures created by MEMS/NEMS fabrication. Novel devices are briefly described, such as a high-power electrostatic nanoactuator, a fast-response tubular anemometer for measuring gas and liquid flows, a nanoprinter, a nanosyringe and optical MEMS/NEMS. The prospects are described for achieving NEMS with tunable quantum properties.

Single-Turn GaAs/InAs Nanotubes Fabricated Using the Supercritical CO2 Drying Technique

We have applied supercritical CO2 drying technique to fabricate free-standing semiconductor nanotubes, in order to solve the problem of tube collapsing caused by the capillary forces in the final drying process. We have successfully fabricated damage-free single-turn nanotubes with ultra-thin walls (lesser than 3 nm) and very high tube-length/wall-thickness ratios (higher than 103), which so far could not been realized. These extremely small and light structures with unique geometry are promising for future nanoelectromechanical systems.

Extremely high response of electrostatically exfoliated few layer graphene to ammonia adsorption

Extremely high gas sensing properties of p-type few layer graphene flakes exfoliated from highly oriented pyrolytic graphite have been demonstrated. The current response to ammonia adsorption is strongly dependent on film thickness and is higher than that for graphene by 1-8 orders of magnitude. A maximal response was found for sample thickness ∼ 2 nm. The effect is attributed to the formation of multiple p-n-p junctions at the grain boundaries in the polycrystalline graphene flakes exposed to ammonia-containing ambient.

Manufacturing chiral electromagnetic metamaterials by directional rolling of strained heterofilms

We show that THz chiral metamaterials consisting of large regular arrays of metal–semiconductor microhelices can be manufactured from strained heterofilms by directional rolling. We also report the results of an experimental study of the electromagnetic properties of such arrays.

Comparison of various methods for transferring graphene and few layer graphene grown by chemical vapor deposition to an insulating SiO2/Si substrate

The objective of this study is to compare the results of transferring graphene and few layer graphene (FKG) up to 5 nm thick, grown by chemical vapor deposition (CVD) at a reduced pressure to a SiO2/Si substrate using four different polymer films. The chosen transfer methods are based on the most promising (according to published data) materials: polymethyl methacrylate, polydimethylsiloxane, thermoscotch, and polycarbonate. It is shown that the most promising transfer method (minimum resistance and maximum carrier mobility) lies in the use of polycarbonate thin films with their dissolution in chloroform. In this case, the following parameters are steadily obtained: the graphene and FLG resistance is 250–900 Ω/□ and the carrier mobility is 900–2500 cm2/(V s).

Terahertz-range chiral metamaterials based on helices made of metal-semiconductor nanofilms

Chiral metamaterials of the terahertz range are formed by means of rolling of strained nanofilms. Structural elements of these metamaterials are metal-semiconductor microhelices. Resonant optical activity of new metamaterials in the terahertz range is demonstrated. Arrays of model wire helices are formed and tested in the microwave range.

Polarization rotation of THz radiation by an array of helices.

Novel approach to controlling polarization of THz radiation is introduced. Polarization plane rotation of transmitted wave by a monolayer of precise microhelices was demonstrated by experiments on the Novosibirsk free electron laser. It had strongly resonant character. Modulation of polarization opens up new possibilities in communication, biomedical, chemistry, security, imaging and spectroscopy applications.