Vladimir I. Shashkin

1/F Noise In Si Delta‐Doped Schottky Diodes

The model of Schottky diode with δ‐doping is suggested. This one is aimed for the determination of technological areas of the diode, which are responsible for the 1/f noise. Series resistance Rb of base and contacts, and the possible leakage Ileak are taken into account. Parameters of the diode are defined from the analysis of the current‐voltage characteristic. For an explanation of experimental data the model of fluctuations in the charge of non‐compensated donors in δ‐layer of Schottky junction (ΔNs‐model) is suggested. The analysis of the 1/f noise spectrum allows assuming that, in investigated diodes, on 106 atoms of main impurity there are 1–10 atoms of extraneous impurity the ionization energy of which may stochastically be modulated.

W-Band Rectenna Coupled With Low-Barrier Mott Diode

Design and characterization of a W-band rectenna, consisting of a 2 × 2 patch sub-array integrated with matching elements and rectifying circuitry is presented. The key element of the rectenna is a Mott diode that has permitted considerable improvement of RF-to-DC conversion efficiency in comparison with commercially available GaAs mm-wave diodes. The experimental setup was equipped by two focusing lenses, allowing a concentration of RF power within the beam spot of a 1 cm diameter at a distance of 1 m. The tuneable W-band source delivering 0.4 W RF CW power was employed to perform large-signal experiments and to measure load characteristics of the rectenna. The measured RF-to-DC conversion efficiency with the single Mott diode is approximately 17%, which is approximately 5 times higher than the commercial counterpart (Microsemi).

Monocrystalline InN Films Grown at High Rate by Organometallic Vapor Phase Epitaxy with Nitrogen Plasma Activation Supported by Gyrotron Radiation

InN hexagonal monocrystalline films were grown on yttria-stabilized zirconia (YSZ) (111) and Al2O3(0001) by the organometallic vapor phase epitaxy method with nitrogen activation in the electron cyclotron resonance discharge, supported by gyrotron radiation. The film growth rate reached 10 µm/h. In this paper, we present data on the morphology, structure, and photoluminescence properties of the grown films.

Indium Nitride Film Growth by Metal Organic Chemical Vapor Deposition with Nitrogen Activation in Electron Cyclotron Resonance Discharge Sustained by 24 GHz Gyrotron Radiation

We report the results of the first experiments on the growth of indium nitride films by electron cyclotron resonance plasma-enhanced metal organic chemical vapor deposition. Discharge sustained by the radiation of a technological gyrotron with a frequency of 24 GHz and power up to 5 kW was used to provide active nitrogen flow. The use of higher frequency microwave radiation for plasma heating provides a higher plasma density, and more active nitrogen flow. Mirror-smooth homogeneous hexagonal InN films were grown on ittria-stabilized zirconia and sapphire substrates. It was shown that single-crystal InN films can be grown on Al2O3 (0001) substrates if a double buffer layer of InN/GaN is used. The growth rate of 1 µm/h was demonstrated in this case. Film properties are studied by optical and electron microscopies, secondary ion mass spectroscopy, X-ray diffraction, and photoluminescence.

Structure and properties of porous GaAs

In this paper we report the first results obtained in the study on the properties of porous GaAs (P-GaAs) produced by electrochemical etching in electrolytes on the basis of hydrofluoric acid. As the initial material we used monocrystalline n- and p-type (100)GaAs substrates Te- and Zn-doped to 2*1018 cm-3 and 6*1018 cm-3, respectively. The substrates were subjected to chemical-mechanical and diamond-paste polish. Etching was performed in an electrolytic cell with a platinum cathode in the galvanostatic regime with anode current densities ranging from 5 to 150 mA/cm2. We were interested in P-GaAs layers with thicknesses from 0.5 to 50 micrometers. The methods used in the study of P-GaAs samples included x-ray diffractometry, electron microscopy, x-ray microanalysis, secondary ion-mass spectroscopy, electrochemical C-V profiling and photoluminescence.

Structure and Algorithms of SL-AV Atmosphere Model Parallel Program Complex

We present recent modifications of the SL-AV global atmosphere model parallel structure and algorithms. The modification of the hybridMPI+OpenMP parallelization structure as well as new parallel I/O system is described. The new multigrid algorithm for solving the linear algebraic equations systems arising from discretization at the reduced latitude-longitude grid is introduced and the convergence results for this method are presented.

Further Development of the Parallel Program Complex of SL-AV Atmosphere Model

The SL-AV global semi-Lagrangian atmosphere model is applied to the operational medium-range weather forecast at Hydrometeorological center of Russia. The works on increasing the code scalability and using future computer architectures are described. The scalable parallel multigrid algorithm for solving the linear algebraic equations systems is implemented. It is expected that the multigrid algorithm will be used instead of direct algorithm based on fast Fourier transforms requiring global communications. The results for convergence and strong scalability of the multigrid method are given.

Photoresponse of thin films of pure and mixed molecular semiconductors in the NIR range

Thin molecular layers composed of phthalocyanine type compounds were deposited on various substrates and characterized. In particular, the spectral dependence of dc current in pure and mixed films in the near infrared was examined. It was shown that these materials can be sensitive to illumination in the range of 1.1-1.6 /spl mu/m depending on the compound structure and the film composition.

Transport in narrow minigap superlattices and the terahertz Bloch oscillator

Transport properties of GaAs–GaAlAs weak barrier superlattices are studied by computer simulation and observation of current–voltage curves and terahertz emission. Existence of terahertz dynamic negative differential conductivity is demonstrated in the simulation. The observed terahertz emission is considered as due to incoherent Bloch oscillation emission. Prospects for the terahertz Bloch oscillator based on such superlattices are discussed.

Simple method for reconstructing the doping fine structure in semiconductors from C–V measurements in an electrolytic cell

A simple method is proposed for reconstructing the doping fine structure in semiconductors from capacitance-versus-voltage measurements with electrochemical etching. The method makes it possible to determine the doping profile directly from the semiconductor surface and provides resolution on scales of less than the Debye screening length. Numerical calculations confirm that the doping profile in semiconductors can be reconstructed with a resolution of several nanometers.