Computer simulation of the growth of heterostructure systems

We have investigated the growth of heterostructures with high lattice mismatch and the growth of quantum wires on the top of ridges and through shadowing masks. Simulations are performed within a Monte Carlo scheme using tetrahedral lattice structure of semiconductor materials. It is shown that results of different simulations present similarities that we attribute to the primary role of kinetic effects as the driving force during epitaxial growth. The formation of 3D islands showing (111) facets, or (111) side walls when depositing through a shadowing mask, has been observed. The facets are of better quality than the top (001) surface because of the higher mobility of atoms on these facets.     

Nano- and micro-range mechanical characteristics of sylvite grain

The paper discusses the indentation testing of sylvite grain using scanning probing microscope Dimension ICON and facility NanotTest-600. The authors present the approximated processing procedure for experimental curves and compare the obtained values of hardness and elastic modulus at different scale levels.     

Comparison of Programming Methods in Heidenhain and Fanuc CNC Systems

The functional capacities of the Heidenhain and Fanuc CNC systems are analyzed by comparing the control programs used in the machining of housing components [1–5].     

Effect of fast protons and neutrons on charge-coupled devices

Sony ICX 259AL CCD matrices were irradiated by proton and neutron beams of a synchrocyclotron of the Petersburg Nuclear Physics Institute. The data on production cross sections, as well as the spatial and time distributions of pixels of the irradiated matrices with high dark current, are presented. The experimental data are compared with the calculation results.     

Properties of silicon films grown under different pressures in a plasma-forming system

The influence of the working-gas pressure on the properties of thin silicon films synthesized by dc magnetron sputtering is investigated. Films obtained under lower pressures are characterized by lower roughness and resistivity. These features can qualitatively be explained by the longer free particle path in the deposition flux under lower pressure.     

Effective harvesting,detection, and conversion of IR radiation due to quantum dots with built-in charge

We analyze the effect of doping on photoelectron kinetics in quantum dot [QD] structures and find two strong effects of the built-in-dot charge. First, the built-in-dot charge enhances the infrared [IR] transitions in QD structures. This effect significantly increases electron coupling to IR radiation and improves harvesting of the IR power in QD solar cells. Second, the built-in charge creates potential barriers around dots, and these barriers strongly suppress capture processes for photocarriers of the same sign as the built-in-dot charge. The second effect exponentially increases the photoelectron lifetime in unipolar devices, such as IR photodetectors. In bipolar devices, such as solar cells, the solar radiation creates the built-in-dot charge that equates the electron and hole capture rates. By providing additional charge to QDs, the appropriate doping can significantly suppress the capture and recombination processes via QDs. These improvements of IR absorption and photocarrier kinetics radically increase the responsivity of IR photodetectors and photovoltaic efficiency of QD solar cells.     

Light-emitting pnn-heterodiode with additional heterojunction in the n-base

It is shown that a p⁺nn⁺-heterodiode with an additional nn-heterojunction in the n-base can be a very effective light-emitting phototransistor or transistor. A depletion layer of the new intermediate heterojunction splits the n-base into two new bases: wider bandgap phototransistor (transistor) base 1 and narrower bandgap light-emitter base 2. A coefficient of light-to-light conversion (of an input light absorbed in base 1 into an output light emitted in base 2) can be very high due to very high phototransistor gain. Effects of avalanche multiplication in the depletion layer of the intermediate heterojunction, edge multiplication in an accumulation layer of the same junction and thermionic electron emission across a conduction band discontinuity barrier are taken into account. Various material systems appropriate for implementation of the considered device are discussed.     

Characteristics of the stress–strain state of annular welded joints in pipelines made of low-carbon austenitic steel

The welding technology using Russian welding materials is described and the nature of formation of residual welding stresses in annular welded joints in pipelines of 3161 low-carbon austenitic steel is outlined. The distribution of stresses in the welded joint at elevated temperatures is simulated.     

Inhibited lubricants for protecting gas-carrier and industrial equipment from corrosion

It was shown that use of inhibited lubricants is an effective method of protecting gas commercial and carrier equipment from corrosion, particularly hydrogen sulfide corrosion. A new inhibited turbine oil, Tp-32R, was developed; it differs from the widely used Tp22s turbine oil due to the higher protective and antiwear properties. The new oil underwent classification tests and tests for compliance with the requirements of Gazprom STO.