This paper will review the top down technique of ICP etching for the formation of nanometer scale structures. The increased difficulties of nanoscale etching will be described. However it will be shown and discussed that inductively coupled plasma (ICP) technology is well able to cope with the higher end of the nanoscale: features from 100nm down to about 40nm are relatively easy with current ICP technology. It is the ability of ICP to operate at low pressure yet with high plasma density and low (controllable) DC bias that helps greatly compared to simple reactive ion etching (RIE) and, though continual feature size reduction is increasingly challenging, improvements to ICP technology as well as improvements in masking are enabling sub-10nm features to be reached. Nanoscale ICP etching results will be illustrated in a range of materials and technologies. Techniques to facilitate etching (such as the use of cryogenic temperatures) and techniques to improve the mask performance will be described and illustrated.

The direct current (dc) glow discharge plasma parameters and active species kinetics in HCl-X (X = Ar, N₂, H₂, Cl₂, O₂) mixtures were studied using both plasma diagnostics Langmuir probes and modeling. The 0-dimensional self-consistent steady-state model included the simultaneous solution of Boltzmann kinetic equation, the equations of chemical kinetics for neutral and charge particles, plasma conductivity equation and the quasi-neutrality conditions for volume densities of charged particles as well as for their fluxes to the reactor walls. The data on the steady-state electron energy distribution function, electron gas characteristics (mean energy, drift rate and transport coefficients), volume-averaged densities of plasma active species and their fluxed to the reactor walls were obtained as functions of gas mixing ratios and gas pressure at fixed discharge current.

The multiprobe Langmuir measurement on-wafer tool for microelectronics ICP reactors was developed. It allows measurements of electron temperature, ion concentration, plasma potential and floating potential directly on chuck. Homogeneity of He and Ar plasmas (electron temperature and negative ion concentration) were measured, and causes of different distribution patterns were discussed.

The influence of atomic hydrogen treatment on two-layer thin-film Cu/Ge system deposited on i-GaAs substrate was investigated. It was established that the treatment in an atomic hydrogen flow with density 10¹⁵ at./(cm²•s) at a room temperature for 5 min results the solid state interdiffusion of Cu and Ge thin films and polycrystalline CuGe alloy formation with the vertically oriented grains.

In a silicon wafer, temperature oscillations observed in a thermal chamber of the rapid thermal annealing set up are investigated in the conditions corresponding to a bistable behavior of a wafer. Oscillations with a typical period near ~400 s are observed at temperatures corresponding to the unstable branch of the s-shaped transfer characteristic of the wafer. Temperature behavior of the wafer at the different regimes of heat exchange is analyzed and it is shown that the oscillations depend on the availability of the negative feedback between the wafer and water-cooled pedestal, through which the heat output is released from the wafer. Oscillation excitation mechanism in such a heat system is offered and the theoretic model of the oscillations is derived. Estimations of the oscillation period obtained by the use of the theoretical model fall in the range between 10³ and 10⁴ s.

Metamorphic In_хAl_1–хAs buffer design influence on electrophysical and structural properties of the MHEMT nanoheterostructures was investigated. Electrophysical properties of the nanoheterostructures were characterized by Hall measurements, while the structural features were described with the help of transmission electron microscopy. The strained superlattices inserted in the metamorphic buffer are shown to filter threading dislocations preventing their penetration in active region. Moreover, the increase of period number in superlattices enhances such effect. Step-graded metamorphic buffer permitted to reach the minimal surface roughness with rather high electron mobility.

Furnace annealing, cw- and pulse laser treatments were applied for crystallization of amorphous Si nano-layers and Si nanoclusters in SiN_x-Si₃N₄ and Si-SiO₂ multilayer nanostructures. The as-deposited and annealed structures were studied using optical methods and electron microscopy techniques. The influence of hydrogen on crystallization and formation of Si nanoclusters was studied. Regimes for pulse laser crystallization of amorphous Si nanoclusters and nanolayers were found. This approach is applicable for the creation of dielectric films with semiconductor nanoclusters and silicon nanostructured films on non-refractory substrates for all-silicon tandem solar cells.

In this report we present the analysis of I-V curves for MIS-structures like silicon substrate / nanodimensional polyelectrolyte layer / metal probe (contact) which is promising for biosensors, microfluidic chips, different devices of molecular electronics, such as OLEDs, solar cells, where polyelectrolyte layers can be used to modify semiconductor surface. The research is directed to investigate the contact phenomena which influence the resulting signal of devices mentioned above. The comparison of I-V characteristics of such structures measured by scanning tunnel microscopy (contactless technique) and using contact areas deposited by thermal evaporation onto the organic layer (the contact one) was carried out. The photoassisted I-V measurements and complex analysis based on Simmons and Schottky models allow one to extract the potential barriers and to observe the changes of charge transport in MIS-structures under illumination and after polyelectrolyte adsorption. The direct correlation between the thickness of the deposited polyelectrolyte layer and both equilibrium tunnel barrier and Schottky barrier height was observed for hybrid structures with polyethylenimine. The possibility of control over the I-V curves of hybrid structure and the height of the potential barriers (for different charge transports) by illumination was confirmed. Based on experimental data and complex analysis the band diagrams were plotted which illustrate the changes of potential barriers for MIS-structures due to the polyelectrolyte adsorption and under the illumination.

In this work showed the possibility of creation high capacity thin-film lithium batteries with the Si-CNT nanocomposite anodes. Synthesized multiwall carbon nanotubes were covered by amorphous silicon with magnetron sputtering. Developed method of formation nanostructured composite is simple, efficient and compatible with widely spread equipment. As s result, designed anode structures with deposited Si thickness of 260 and 390 nm exhibit high specific capacities (more than 2500 mAh/g) and significantly improved cycling stability versus silicon films.

To create a molecular transistor, that is capable to operate in single-electron regime at room temperature, nanogap of several nanometers between electrodes is needed. Such nanogaps can be obtained by electromigration. In this work the technique of the creation of nanowire samples suitable for electromigration is described. Nanowires were formed on a substrate without buffer metallic layer to provide best conditions for electromigration process.

Integrated electrodes of molecular transistor were obtained. Electrodes includes thin-film Au strips with a 2 - 3 nm gap between them and Al gate electrode covered by Al2O3 oxide. The gap formation were made by electromigration technique and self-breaking process. Small (3 - 5 nm) gold nanoparticle were placed into the gap by self assembling. IV curves were measured at room temperature. These IV curves demonstrated single-electron conductivity of system. Such integrated system of electrodes is suitable to be the source-drain electrodes of planar single-electron transistors based on nano-particles or molecules.

We investigated structural perfection of porous gallium arsenide layers formed in GaAs (001). Different modes of electrochemical etching of n-type GaAs(001) substrates in fluoride-iodide aqueous electrolytes were used to form porous layers. Their structural properties were investigated by high resolution X-ray and synchrotron radiation diffraction and electron microscopy (SEM, TEM) techniques. It was shown that a single current pulse with a high magnitude forms a discontinuous porous layer with a smooth surface. Subsequent etching with a relatively low current density forms a homogeneous porous structure in the depth with approximately 30% porosity. The porous layer thickness can be varied from a few microns to several tens of microns depending on the etching time. The lattice parameter of porous GaAs layers along the surface normal is decreased by a factor of 1.5×10^-4 compared to the GaAs substrate. This contraction is related to the formation of vacancy type structural defects as revealed by the measurement of x-ray diffuse scattering.

The initial structures of two types – HfO₂(50 nm)/Si (100) and W(150 nm)/HfO₂(5 nm)/Si (100) – were prepared by radio frequency magnetron sputtering (RF-MS) in Ar⁺-plasma and further were subjected to the annealing at 500-950 °C followed by forming an ohmic contact to Si-substrate. Investigation of the first type structures show that differences in various crystalline modifications and kind of I-V curves strongly depend on conditions of growth of the HfO₂ films during RF-MS process where RF bias U_bias, applying to the substrate, is an effective parameter for quality and growth process control of the HfO₂ films. For the second type structures, the ultrathin HfO₂ films were grown at U_bias= -7 V, then an effect of RTA at 950 °C in a neutral atmosphere on both electrical characteristics and chemical state at interfaces was studied. In comparison with as-deposited structures, RTA leads to decrease in the both the maximum specific capacitance in accumulation of C-V characteristics (by 30 %) and the dielectric constant (from 27 to 23). The thermally activated processes of formation of WO_x phase at the W/HfO₂ interface and Hf-silicate phase (HfSi_xO_y) at the HfO₂/Si (100) interface were observed. The total thickness of formed oxide layer exceeded the thickness of as-deposited HfO₂ film by 30 %.

A quantum-mechanical model for describing thermodynamic properties of an ensemble of ideal antiferromagnetic nanoparticles with axial magnetic anisotropy is developed in the first approximation of slowly relaxing macrospins of magnetic sublattices. This model clarifies principally the difference in thermodynamic behavior of ferromagnetic and antiferromagnetic particles revealed in spectroscopic measurements. In particular, one can now qualitatively describe specific (non-superparamagnetic) temperature evolution of the ⁵⁷Fe Mössbauer spectra of antiferromagnetic nanoparticles, which has been often observed for almost half a century and looks like a quantum superposition of well resolved magnetic hyperfine structure and single line (or quadrupolar doublet of lines) with the temperature-dependent partial spectral areas. This approach can be easily generalized for describing uncompensated antiferromagnetic and ferrimagnetic nanoparticles as well as magnetic relaxation processes, which would allow one to take directly into account the magnetic nature inherent to the particles in analyzing a large amount of experimental data collected so far.

In order to extract quantitative information about characteristics of the magnetic nanoparticles in a media it is necessary to define a model of the magnetic dynamics for treating self-consistently the whole set of the experimental data, particularly, the evolution of Mössbauer spectral shape with temperature and external magnetic field as well as the magnetization curves. We have developed such a model and performed such an analysis of the temperature- and magnetic field-dependent spectra and magnetization curves by the example of nanoparticles injected into laboratory mice. This allowed us to reliably evaluate changes in the characteristics of the residual particles and their chemical transformation to paramagnetic ferritin-like forms in animals organs as a function of time. Actually, the approach makes it possible to quantitatively characterize biotransformation and biodegradation of magnetic nanoparticles delivered in a living organism.

The technique of finite difference equations (Kostyuchenko V.V. method) is used for an analytical investigation of field-induced transitions in ferrimagnetic chains of spins. The chains of spins of even length are considered. The analytical dependencies of critical field values determining the stability of ferromagnetic and antiferromagnetic phases on the spins number are obtained.

In view of high-speed application of microwave transmission lines the coherent quantum effects in conducting components of transmission lines were considered. When a characteristic coherence length of the electronic wave functions becomes to be comparable with a length of the transmission line, such quantum effects make it necessary to consider the line as a “quantum” transmission line. We discuss a kind of such quantum effects related to the Einstein- Podolsky-Rosen paradox and analyze their influence on the properties of transmission lines and a possibility to increase a speed of signal transmission by using these quantum properties. Brief review of alternatives and phenomena related to the problem of Einstein-Podolsky-Rosen paradox is presented. On the example of the magnetic perturbation traveling in a closed superconducting microwave slotline the features of the quantum-mechanical reaction of this completely coherent macroscopic system in response to the local impact excitation of its part is considered. The transient processes are analyzed in the context of the Einstein-Rosen-Podolsky paradox.

This paper reviews recent advances in terahertz-wave generation in graphene toward the creation of new types of graphene terahertz lasers. Fundamental basis of the optoelectronic properties of graphene is first introduced. Second, nonequilibrium carrier relaxation/recombination dynamics and resultant negative terahertz conductivity in optically or electrically pumped graphene are described. Third, recent theoretical advances toward the creation of current-injection graphene terahertz lasers are described. Fourth, unique terahertz dynamics of the two-dimensional plasmons in graphene are discussed. Finally, the advantages of graphene materials and devices for terahertz-wave generation are summarized.

The statistical characterization and reliability results for a One Time Programmable (OTP) non-volatile memory that uses a p-type cobalt salicide polysilicon (CoSi₂) fuse for a 0.25μm technology are presented. The fuse element consists of a minimum width 80 Ohm poly resistor with rectangular head connections surrounded by oxynitride and passivating oxide layers. A low resistance transistor is used to control the programming voltage rise and fall time of the fuse. The chosen programming voltage and time at 27°C causes local Joule heating and electromigration of the Cobalt with dissolution of the polysilicon and diffusion of the p-type dopant to the anode. A characterization methodology was developed for determining the optimum programming conditions to form an amorphous, void free fuse with a final resistance of greater than 1MOhm without disturbing the passivating films. The process window characterization showed that thinner CoSi₂ films resulted in significant reduction of partially blown fuses in the tail of the resistance distributions. The JEDEC HTOL/HTSL specified methods were used to stress 3.9 million programmed fuses at 125°C/150°C for up to 2000 hours which resulted in no bit failures for three lots tested. The resistance drift for programmed fuses after thermal and electrical stress showed no significant change in the distributions.

Technology of formation for nanostructured magnetic materials on silicon substrate with a mean nanostructures size of ~ 25 nm and a narrow size distribution of these nanostructures was elaborated in the work. Single-domain magnetization character for some of the nanostructures was obtained. Completely optical magnetization of nanostructures was performed by circularly-polarized light at room temperature.

The Cu metalized GaAs pHEMTs using developed Pd/Ni/Ge/Mo/Cu and Cu/Ge based ohmic contacts and Ti/Mo/Cu 150 nm T-shape gate has been successfully fabricated for the high-frequency applications. The fabricated Cu metalized GaAs pHEMTs with Pd/Ni/Ge/Mo/Cu and Ge/Cu ohmic contacts had a transconductance peak of 440 and 320 mS/mm, maximum stable gain value was about 18.8 and 14.5 dB at frequency 10 GHz and current gain cut-off frequency was about 100 and 60 GHz, accordingly. The performance of the fully Cu metalized atomic hydrogen treated GaAs pHEMT with Cu/Ge ohmic contacts and Ti/Mo/Ge/Cu based T-gate was investigated. It was found, that such processing in an atomic hydrogen flow with density 10¹⁵ at. cm² s^-1 at room temperature during 5 min leads to reduce the contact resistance of Ge/Cu ohmic contacts by 1.6 times. The reduction in specific contact resistance is apparently caused by the action of the hydrogen atoms which minimise the rate of the oxidizing reactions and activate solid phase reactions forming the ohmic contact during the thermal treatment process. The fabricated fully Cu metalized GaAs pHEMT with atomic hydrogen processing had a transconductance peak of 380 mS/mm and current gain cut-off frequency was about 80 GHz. It is similar with performance of conventional gold base devices. The experimental results allow to consider the copper as perspective gold replacement in the GaAs MMIC production.

The low-frequency noise behavior of nanoscaled fully-depleted silicon-on insulator (SOI) finFETs is investigated and the perspectives of the noise method as a non-destructive diagnostic tool are revealed. The analysis of the (1/f)^γ McWhorter noise observed at zero back-gate voltage showed that the trap concentration N_ot appears to be lower in the case of devices with HfSiON/SiO₂ gate dielectric with the uniaxial strain in the inversion channel while the implementation of the HfO₂/SiO₂ gate stack and the biaxial strain tend to increase the value of N_ot. The analysis of the back-gate-induced (BGI) and linear kink effect (LKE) Lorentzian noise observed when the back interface is biased in accumulation allowed to estimate the values proportional to equivalent capacitance C_eq. Their front-gate voltage dependencies appear to be different for the devices with HfSiON/SiO₂ and HfO₂/SiO₂ gate dielectric. Also the values proportional to density of the electron-valence-band tunneling currents j_EVB were found for the devices studied. The influence of the strain-inducing techniques and gate dielectric type on the values discussed is revealed.

Electrodes for molecular transistor with the gaps between them within 5 nm width’s range were created. On the first step suspended electrodes-blanks with 30 nm gaps was fabricated with a standard bilayer mask technology and electron beam lithography. Then wet etching in a 6% solution of hydrofluoricacid buffered with hydrofluoride of ammonium makes possible to suspend these electrodes to prevent them from short-circuit at the step of additional evaporation of metal film. The efficiency of narrowing of the gap between source and drain electrodes (as a result of additional deposition of metal film on the preformed and suspended gap) was 50-70% of the deposited film thickness.

Development of physical principles of THz-wave amplification and oscillation is one of problems determining progress in modern solid state electronics towards high frequencies and ultrahigh performance. Novel perspectives are tied with use of resonant tunneling quantum effects, characterized by transient times less than 1 ps, comparable with fast response of superconducting devices. The information about these properties can be obtained from investigation of high-frequency oscillations or current-voltage switching phenomena in resonant-tunneling (RTD) nanostructures. In the paper the results of theoretical and experimental studies of high-frequency properties of RTD elements in subterahertz and terahertz frequency range are presented basing on developed theory of high-frequency response in RTD as well as on experimental high-frequency investigation data and current-voltage switching phenomena investigation results of effects correspondingly related to stationary current characteristics changes in single-quantum-well as well as in doublequantum- well resonant-tunneling diode nanostructures under external electromagnetic electrical field.

The sensitivity of bipolar magnetotransistor with the base in the well - 3CBМТBW has been studied. A low velocity of surface recombination and an extraction of the injected electrons by a base–well р-n junction determined operating mode with a deviation of two flows of charge carriers has been established. The voltage magnetosensitivity (~11 V/T) has been determined.

Lead-zirconate-titanate (PZT) is a typical piezoelectric material with outstanding properties. The preparation behavior of Lead Zirconate Titanate (PZT) composite films comprised of Si, SiO₂, Pt, PZT and Pt for MEMS applications was investigated. The choice of precursors can affect the microstructures and properties of the product, so in this paper we compared the crystallization behavior of PZT films derived from different precursors, stressing the influence of experiment conditions. Dense PZT films were prepared by electrophoretic deposition method (EPD), using commercial powder PZT precursor and metal alkoxide components for the same composition. Some specific comments were underlined about structure of PZT films.

Resonant properties of the three-layer metallic cantilevers with 40 nm thickness are investigated. Two types of the nanocantilevers were fabricated: Cr-Al-Cr and Ti-Al-Ti. Resonant frequencies of the nanocantilevers were determined from the experimentally obtained resonant curves. Cantilever oscillations were excited by the electric force, the registration of the cantilever motion was performed by the optical lever method. Dependencies of the first and the second resonant frequencies on the cantilever length and width were experimentally obtained. The experimental data analysis and the comparison with the theoretical predictions were performed. Relations between the cantilever resonance properties and its dimensions and material are discussed.

Paper presents a new technology for silicon micromachined gyroscope mode matching with mutually spaced eigenfrequencies. The fabrication of gyroscope sensing element is based on double-sided deep reactive ion etching (DRIE) of standard silicon wafer and allows full 3D control of the gimbals and flexures geometry. The developed finite element model allows predicting dynamic characteristics of sensing element versus geometry of flexible suspension beams. Oxidation and successive wet etching of SiO2 layer lead to flexure geometry change (thinning). One-to-one correspondence of measured resonant frequencies and flexures geometry defines the oxidation depth. The mode matching condition is achieved by repeated oxidation-wet etching cycles.

The study was performed on a test step relief structure of monocrystalline silicon. There was experimentally measured the thickness of the natural oxide on this structure consisting of a set of elements (protrusions) with a trapezoidal profile and 2.0 μm step size, upper base about 10 nm, height about 500 nm. The tilt angle of side face with respect to the lower base was 54.7°. The entire structure was covered with a natural oxide film that appeared at room temperature, the thickness of which is being measured using a transmission electron microscope with atomic resolution by the observed pattern in the direct mode resolution of the crystal structure. In order to calibrate the measurements a distance between {111} planes was used. It was shown experimentally, that in the area of this bottom the natural oxide thickness increases from 2.3 ± 0.2 nm in the middle of the bottom to 3.0 ± 0.2 nm and 4.5 ± 0.2 nm at the left and right edges of the bottom, respectively.

During a failure analysis of integrated circuits, containing non-volatile memory, it is often necessary to determine its contents while Standard memory reading procedures are not applicable. This article considers how the state of NVM cells with floating gate can be determined using scanning probe microscopy. Samples preparation and measuring procedure are described with the example of Microchip microcontrollers with the EPROM memory (PIC12C508) and flash-EEPROM memory (PIC16F876A).

Semi empirical model of image formation is proposed for scanning electron microscope (SEM) working in low and high voltage modes with registration of back scattered (BSE) and slow secondary (SSE) electrons. The model is based on analysis of experiments executed with a test object with trapezoidal profile and with large slope angles scanned in a SEM. The model is designated for application in virtual SEM.

Application of virtual instruments to a process of measurements of geometrical characteristics of investigated objects is considered. Methods of construction of virtual instruments on a base of imitators and simulators are discussed. It is demonstrated, that a virtual scanning electron microscope (SEM) can be constructed only on the base of simulator. Examples of work of the virtual SEM in a low-voltage mode and in modes of registration of back scattered electrons (BSE) and slow secondary of electrons (SSE) are given.

Traditional insight of effective probe of scanning electron microscope (SEM) is considered. A contradiction of this insight with experimental results registered at scanning of test objects with the trapezoidal profile and large slope angles by SEM probe is detected. A new insight of effective probe based on analyzes of the experimental results registered by SEM working in a back scattered electron (BSE) mode is proposed.

A scan of trapezoidal protrusions by an electron beam was carried out in a SEM during an hour. This allows detecting some laws of a profile change due to contamination. The detection is based on analysis of distorted protrusion images obtained by the SEM. The greatest distortion of protrusion images was discovered around a scanned area. This distortion is not uniformed in the area (and associated with a non-uniform profile change in that area) that leads to a pitch change of a periodic structure. The protrusion image change in the scanned area is minimal, contrary to perceptible structure profile changes in that area. The latest circumstance allows defining geometrical parameters of a protrusion using a model developed for measurement of these parameters for a non-distorted structure. It was discovered that contamination process of periodic linear structures beyond the scanned area differs from the corresponding process for a flat surface. The difference firstly is due to dissimilar contribution of a volume and surface diffusion of hydrocarbon particles (HCP) that induce the contamination into various structure areas. Secondly it is due to different diffusion velocity of surface HCPs that are moving along and across of stripes with trapezoidal profile and over surfaces with different crystallographic indexes.

It is known that the influence of line edge roughness (LER), formed during lithography and plasma etching processes, on the MOSFET characteristics becomes more critical with downscaling of the device. This is because LER and line width roughness do not scale down with the dimensions of the devices. High values of LER can lead to increase of current leakage and voltage fluctuations and hence cause degradation of circuit performance and yield. However the gate LER is hard to measure by conventional tools. Therefore reliable LER metrology approach is required. In this study conventional AFM technique is used to estimate LER.

Single-walled carbon nanotubes with ultra small diameter are of particular interest for investigation of properties of nanotubes with different chiralities. Density functional theory provides a very effective method for the description of ground-state characteristics of metals, semiconductors and insulators. Here we present the results of a study of band structure, ionization energy, work function and bond energy in carbon nanotubes (with diameters ranged 0.2 – 2.0 nm) carried out within the density functional theory. We have found that chirality strongly affects these parameters in nanotubes of very small diameters where conventional tight-binding models are not appropriate.

This paper presents two novel implementations of the Differential method to solve the Maxwell equations in nanostructured optoelectronic solid state devices. The first proposed implementation is based on an improved and computationally efficient T-matrix formulation that adopts multiple-precision arithmetic to tackle the numerical instability problem which arises due to evanescent modes. The second implementation adopts the iterative approach that allows to achieve low computational complexity O(N logN) or better. The proposed algorithms may work with structures with arbitrary spatial variation of the permittivity. The developed two-dimensional numerical simulator is applied to analyze the dependence of the absorption characteristics of a thin silicon slab on the morphology of the front interface and on the angle of incidence of the radiation with respect to the device surface.

In the paper the nanoelectronic devices based on the resonant tunneling effect are analyzed. In particular, the currentvoltage characteristics of resonant-tunneling diodes (RTD’s) based on Si/Ge, Si/SiGe heterostructures and based on carbon nanotubes (CNT) are calculated using proposed models. The first combined two-band model [1, 2] for calculation of RTD characteristics with account of valence band influence is modified for the case of account of quantum well width deviation. The combined numerical model of RTD is based on the self-consistent solution of Poisson and Schrödinger equations. The developed model provides good agreement with experimental data at room temperature. In the paper the results of simulation according to the proposed model for double-barrier Si/Ge, Si/SiGe RTD’s are obtained. The second and third models for RTD based on CNT are presented. The second model is a simple analytical one. The results of simulation according to this model for devices based on CNT are presented for different values of Fermi energy level. The Fermi energy level depends on the material used for contact system. The third model is a self-consistent one. Comparison of analytical model and self-consistent one is presented. A good agreement of simulation results was obtained only at small voltages. IV-characteristics with larger values of peak current and peak voltages were obtained with the use of the third numerical model. Thus the second model can be only used for rough estimations of characteristics of RTD based on CNT.

Simulation of single-electron devices’ characteristics is one of the prior challenges in nanoelectronics today. The physical model for single-electron device simulation is described in the paper. Our model is based on the self-consistent numerical solution of the Poisson equation with using of Monte Carlo method or master equation. The developed model is modified for the case of account of spatial quantization. The following approximations of the quantum well are used: of the quantum well of infinite depth; of the rectangular quantum well of finite depth; of the parabolic quantum well. The model enables obtaining single-electron devices IV-characteristics changing as a function of parameters of material and design. The programs, implementing the suggested model, were included into the simulation system of nanoelectronic devices NANODEV [1-3] developed for personal computers. The developed model makes it possible to simulate devices of four types: metal, semiconductor, composite and organic ones. Besides, it can be successfully used for simulation of both single- and multi-island single-electron devices. Thus, the proposed model is a universal one. The results of simulation according to the developed model with account of spatial quantization are presented in the paper.

We suggest an approach for determining nanoobjects’ energy spectra depending on its total electric charge. The approach was tested studying golden nanoparticles of different sizes surrounded by ligands of dodecanethiols. Quantum methods of Hartree-Fock and DFT were used to calculate energy spectra and capacitances for such gold nanoparticles consisting of up to 33 atoms of gold. Presence of “extra” levels in energy gap of nanobject’s spectra was revealed. Also dodecanethiol SCH₂(CH₂)₁₀CH₃ ligands influence on the total capacitance and energy spectrum of molecular nanocluster was shown. Finally transport characteristics for gold nanocluster based molecular single-electron transistor (MSET) were calculated using the obtained energy spectra.The simple energy spectra structure model used in the present work may allow single-electron transistor (SET) simulation for larger molecular systems.

In this paper we performed 2D and 3D device simulations to analyze the impact of technology scaling on the lattice heating in n-channel bulk silicon and silicon-on-insulator MOS transistors with gate lengths from 0.5 to 0.1 um. Maximum lattice temperatures and transistor thermal resistances for different gate lengths and bias voltages were calculated. The increase in device temperature and thermal resistance with transistor scaling was shown.

A model of "parallel" metal-graphene quantum FET nanotransistor with a gate on the Coulomb blockade in the "magic" Ir₅₅ nanocrystals is proposed and designed. This nanotransistor will have a speed of about 2.5 * 10¹¹ Hz and size of 32x32x12 nm³. It is shown that in this model of nanotransistor a source-drain potential is equal to 1.2 V, the threshold for the opening of the gate U_G is equal to 0.4 V and the total current in parallel connected 250 elementary single-electron nanotransistors - crystals of Ir₅₅ is 1.5 * 10^-5 A. This current is approximately equal to the current in experimental terahertz semiconductor nanotransistors. It is shown that gain coefficient for charge is K_q = 1, and the power gain is equal to K_P ~ 3. Such nanotransistor at using inductive-capacitive load could be an element of the integrated circuit - the generator of electro-magnetic waves with a wavelength of 1.2 mm and power density ~ 10⁴ W/cm².

In the present publication, we give an extended discussion to the previously proposed model invented to describe the humplike feature that was observed in the accumulation branch of low-frequency capacitance-voltage (C-V) characteristics of MOS capacitors with oxide-hosted Si nanoparticles (V.A. Stuchinsky et al., Tech. Phys. Letters, 2012, Vol. 38, No. 9, pp. 845–848). In comparison with the above publication, the reasoning leading to this model and the basic properties of the model are outlined in greater detail. In a simple version, the model assumes monopolar injection of electrons or holes into the oxide layer from one of the two MOS contacts (with semiconductor or metal) and their subsequent migration along the linear chains formed by Si nanoparticles in the oxide with a certain spread of tunneling distances in individual chains. Manifestations of the variation of nanoparticle-accumulated charge at the ac frequency in the C-V characteristics of MOS capacitors were examined in computer-aided simulations performed for different arrangements of Si nanoparticles in nanoparticle chains and monopolar injection of holes from the accumulation layer of p-type semiconductor. Discussing most favorable conditions for organization of efficient electroluminescence in film systems with Si nanoparticles, we give qualitative consideration to a more complex case with bipolar injection of charge carriers into the oxide layer from both contacts. Next, we put forward a hypothesis that the capacitance peaks that in some cases were observed in MOS capacitors in strong inversion could be a manifestation of the same hump-feature formation mechanism.

This paper presents a review of different ways of quantum operation descriptions, including operator-sums, unitary representations, Choi-Jamiolkowski state representations and the corresponding chi-matrices, as well as quantum system evolution operators. These models are equivalent, but each one is useful in different applications. The main application of these models is simulation and analysis of quantum computer noisy gates.

In the present paper methods and algorithms of modeling quantum operations for quantum computer integrated circuits design are developed. The results of modeling of practically important quantum gates: controlled-NOT (CNOT), and controlled Z-transform (CZ) subject to different decoherence mechanisms are presented. These mechanisms include analysis of depolarizing quantum noise and processes of amplitude and phase relaxation.

We study the evolution of entanglement in quantum gates in terms of Choi-Jamiolkowski relative states negativity. SQiSW (generated by XY-interaction), CNOT and CZ gates are considered in ideal case and under amplitude and phase relaxation. In addition, we consider an important task of analyzing entanglement of “pure” noise, which is obtained by deducting an ideal gate from a noisy one.

As optical systems are one of the candidates for implementation of a scalable quantum computer, it is important to develop an adequate method of description of both quantum states of light and operations performed by optical elements. Using the concept of chi-matrix representation of quantum operations and Choi-Jamiolkowski isomorphism we expand Jones calculus to allow description of evolution of mixed polarization states in linear optical systems. The developed method is then used to give a full description of polarization echo effect, which was described in ¹ based on an analogy between the effects of polarization optics and spin dynamics. Theoretical predictions are confirmed by reconstructing operations performed by a series of quartz waveplates using quantum process tomography protocols.

We study dynamical correlations of two coupled large spins depending on the time and on the spin quantum numbers. In the high-temperature approximation, we obtain analytical expressions for the mutual informations, quantum and classical parts of correlations. The latter was obtained performing the non-orthogonal projective (POVM) measurements onto the spin coherent states of two spins or one spin, as well as by means of the orthogonal projective measurement of von Neumann. Contribution from quantum correlations is much less than that from classical ones and decreasing with the increase in spin quantum numbers at short times. However, it is not so in a time equal to half of the quantum period.

Two component Bose-Einstein condensates (BECs) have been recently shown to be viable systems for storing and manipulating quantum information. Unlike standard single-system qubits, the quantum information is duplicated in a large number of identical bosonic particles, thus can be considered to be a “macroscopic” qubit. One of the difficulties with such a system is how to effectively interact such qubits together in order to transfer quantum information and create entanglement. Here we discuss quantum state transfer using cavities containing two-component BECs coupled by optic fiber with a goal to apply this technique for quantum networking with BECs.

We propose a scheme of quantum information processing with NV-centers embedded inside diamond nanostructure. Single NV-center placed in the cavity plays role of an electron spin qubit which evolution is controlled by microwave pulses. Besides, it couples to the cavity field via optical photon exchange. In their turn, neighbor cavities are coupled to each other through the photon hopping to form a bus waveguide mode. This waveguide mode overlaps with all NVcenters. Entanglement between distant centers is organized by appropriate tuning of their optical frequency relative to the waveguide frequency via electrostatic control without lasers. We describe the controlled-Z operation that is by one order of magnitude faster than in off-resonant laser-assisted schemes proposed earlier. Spectral characteristics of the onedimensional chain of microdisks are calculated by means of numerical modeling, using the approach analogous to the tight-binding approximation in the solid-state physics. The data obtained allow to optimize the geometry of the microdisk array for the effective implementation of quantum operations.

We consider the problem of time-optimal realization of the quantum Fourier transform gate for a single qudit with number of levels d from 3 to 8. As a qudit the quadrupole nucleus with spin I > ½ controlled by NMR is considered. We calculate the dependencies of the gate error on the duration of radio-frequency pulse obtained by numerical optimization using Krotov-based algorithm. It is shown that the dependences of minimum time of QFT gate implementation on qudit dimension are different for integer and half-integer spins.

We considered the interaction of semiconductor quantum register with noisy environment leading to various types of qubit errors. We analysed both phase and amplitude decays during the process of electron-phonon interaction. The performance of quantum error correction codes (QECC) which will be inevitably used in full scale quantum information processors was studied in realistic conditions in semiconductor nanostructures. As a hardware basis for quantum bit we chose the quantum spatial states of single electron in semiconductor coupled double quantum dot system. The modified 5- and 9-qubit quantum error correction (QEC) algorithms by Shor and DiVincenzo without error syndrome extraction were applied to quantum register. 5-qubit error correction procedures were implemented for Si charge double dot qubits in the presence of acoustic phonon environment. ¬-matrix, Choi{Jamio lkowski state and measure of decoherence techniques were used to quantify qubit faulttolerance. Our results showed that the introduction of above quantum error correction techniques at small phonon noise levels provided quadratic improvement of output error rates. The effciency of 5-qubits quantum error correction algorithm in semiconductor quantum information processors was demonstrated.