Victor Ya. Prinz

Application of semiconductor micro- and nanotubes in biology

Abstract We developed a new technology for fabricating InGaAs/GaAs and GeSi/Si semiconductor micro- and nanoneedles, syringe for intracellular injections. Within this technology, a novel method for directional roll-up of strained heterostructures is proposed, which fits nicely into the well-established integrated-circuit technology. The tubes obtained by this method are mechanically strong enough to many times puncture thick-walled plant cells, and they can be easily integrated into other semiconductor devices to form a “lab-on-a-chip”.

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.

Self-organized arrays of graphene and few-layer graphene quantum dots in fluorographene matrix: Charge transient spectroscopy

Arrays of graphene or few-layer graphene quantum dots (QDs) embedded in a partially fluorinated graphene matrix were created by chemical functionalization of layers. Charge transient spectroscopy employed for investigation of obtained QD systems (size 20–70 nm) has allowed us to examine the QD energy spectra and the time of carrier emission (or charge relaxation) from QDs as a function of film thickness. It was found that the characteristic time of carrier emission from QDs decreased markedly (by about four orders of magnitude) on increasing the QD thickness from one graphene monolayer to 3 nm. Daylight-assisted measurements also demonstrate a strong decrease of the carrier emission time.

Electrical passivation of Si∕SiGe∕Si structures by 1-octadecene monolayers

The passivating effects of organic monolayers of 1-octadecene deposited onto the silicon surfaces of both n and p conductivities were studied for Si∕SiGe∕Si structures grown by molecular beam epitaxy and chemical vapor deposition. Measurements of the capacitance versus voltage and current versus voltage were made on structures covered with the organic monolayer and compared with unpassivated structures covered with native silicon dioxide. The results demonstrate that the organic passivation provides a decrease of surface charge and an increase of carrier concentration in the near-surface layers and/or the SiGe quantum wells.

Tunable properties of few-layer graphene–N-methylpyrrolidone hybrid structures

A few-layer graphene-based hybrid material with high thermal and chemical stability and reproducible and tunable electronic properties was fabricated by intercalation of N-methylpyrrolidone into a few-layer graphene combined with heat treatment. Depending on the process temperature, the obtained material could be produced with the following properties: a broad range of resistivity values (six to seven orders of magnitude) in combination with a high carrier mobility, a tunable band-gap (from 0 up to 3-4 eV) and sp² or sp³ hybridization of carbon atoms. The extremely strong step-like temperature dependence (within 10 °C) of its properties observed in the vicinity of two temperatures, 90 and 200 °C, seems to be important for various applications. The hybrid material opens viable routes to progress in the design of three-dimensional nanostructures.

Free-Standing InAs/InGaAs Microtubes and Microspirals on InAs (100)

A new material system for creating InAs-based free-standing micro- and nanoobjects is proposed. For the first time, InAs/InGaAs microtubes and microspirals were obtained, including tubes containing two-dimensional electron gas, ordered arrays of tubes, and tubes protruding over the substrate edge. First measurements of the electrical conductivity of InAs/InGaAs microtubes were performed.

Terahertz metamaterials and systems based on rolled-up 3D elements: designs, technological approaches, and properties

Electromagnetic metamaterials opened the way to extraordinary manipulation of radiation. Terahertz (THz) and optical metamaterials are usually fabricated by traditional planar-patterning approaches, while the majority of practical applications require metamaterials with 3D resonators. Making arrays of precise 3D micro- and nanoresonators is still a challenging problem. Here we present a versatile set of approaches to fabrication of metamaterials with 3D resonators rolled-up from strained films, demonstrate novel THz metamaterials/systems, and show giant polarization rotation by several chiral metamaterials/systems. The polarization spectra of chiral metamaterials on semiconductor substrates exhibit ultrasharp quasiperiodic peaks. Application of 3D printing allowed assembling more complex systems, including the bianisotropic system with optimal microhelices, which showed an extreme polarization azimuth rotation of 85° with drop by 150° at a frequency shift of 0.4%. We refer the quasiperiodic peaks in the polarization spectra of metamaterial systems to the interplay of different resonances, including peculiar chiral waveguide resonance. Formed metamaterials cannot be made by any other presently available technology. All steps of presented fabrication approaches are parallel, IC-compatible and allow mass fabrication with scaling of rolled-up resonators up to visible frequencies. We anticipate that the rolled-up meta-atoms will be ideal building blocks for future generations of commercial metamaterials, devices and systems on their basis.

Three-axis Hall transducer based on semiconductor microtubes

A three-axis Hall transducer based on GaAs/AlGaAs/InGaAs microtubes has been fabricated. The possibility of simultaneous measurement of all the three magnetic field components with such a transducer was demonstrated. It was also shown possible to pack the free-standing parts of the transducer with polydimethylsiloxane for protection of those parts from mechanical actions.

Nano-Fabricated Hot-Tubes for Flow Measurements

New type of sensor for thermal anemometry – hot-tube sensor is presented. Some details on manufacture procedure and mechanical properties of sensors are given. Hot-tube response on pulse heating is checked. It is found that time constant of hot-tube is 80 times less that hot-wire one. Pulsations measurements in subsonic flow show that hot-tube does not require thermal inertia compensation for frequencies up to 20-40 kHz and that hot-tube has much better signal/noise ratio than hot-wire. I. Introduction HE fast-responsible flow microsensors with high spatial and temporal resolution are necessary for the solution of key challenges in aero-gas-dynamics. One of such unresolved problems is the problem of the laminarturbulent transition and description of turbulent flows. The measurement of the high-frequency oscillations of low amplitude at the early stage of the laminar-turbulent transition is an important task 1 . The only sensor fit to measure the disturbances in the high-speed flows is a hot-wire probe, its sensitive element being a thin metal wire or film. The time constant of these sensors normally lies within the range of 0.2 – 1 ms, and is limited, in the case of wire sensors, by the wire thermal capacity; and in the case of film sensors – by the heat exchange with the substrate 2,3,4,5,6 . As a result, the sensitivity of the hot-wire anemometers rapidly decreases at the frequencies above 1 kHz, and becomes insufficient to measure the high-frequency (higher than 100 kHz) pulsations, which are typical for the high-speed flows. A search for new methods of batch production of the anemometers sensors involving integral circuit technology is active in the world. Attempts are made to increase the sensitivity with the aid of suspended bridges or membranes 3-6, 7 . Recently 8 an original method of production of monocrystal semiconductor micro- and nano-tubes has been proposed and realized. The method is based on self-rolling of a thin heterofilms detached from the substrate under the action of inner mechanics stresses (Fig. 1). The diameter of the tubes formed in this way can be precisely controlled in the range of 100 µm -2 nm by a proper choice of thicknesses and compositions of the layers in the starting heterostructure. The proposed method has been successfully applied to a number of dielectrics, metals, and semiconductors 8,9, . The purpose of the present paper is to fabricate pilot models of the hot-tube sensors for thermal anemometers from hybrid Metal/GaAs/InGaAs heterofilms using self-scrolling heterostructure technology.

Transverse Magneto-Optical Kerr Effect in Strongly Coupled Plasmon Gratings

Enhancement of magneto-optical response by coupling of propagating with localized plasmons in a structure based on silver and bismuth-substituted ferrite garnet has been numerically studied. It is shown that the absolute value of the magneto-optical response in the examined structure reaches a high value of 0.04, and the structure has a reflection coefficient sufficiently high for a number of practical applications. The strong coupling between localized and propagating plasmons, which caused the significant enhancement of the magneto-optical response, was manifested in the reflection spectrum of the structure in the form of an asymmetric Fano-like resonance. The proposed structure, intended for operation in the near infrared range, is a promising one for solving various problems in magnonics and bionanophotonics.