Redox Properties of Rhodium(III) Oxo-Bridged Carboxylate Complexes

Chemical and electrochemical oxidation of rhodium (III) oxo-bridged carboxylate complexes was studied. The chemical [with O₃ and Ce(IV) salts] or electrochemical (at potentials of 1.00-1.20 V) oxidations of the binuclear complexes [Rh₂(-O)(-O₂CCH₃)₂(H₂O)₆]^{2 +} and [Rh₂(-O)(-O₂CCF₃)₂(H₂O)₆]^{2 +} leads to the superoxo complexes [Rh₂(-O)(O₂-)(-O₂CCH₃)₂(H₂O)₅]⁺ and [Rh₂(-O)(O₂ ^-)(-O₂CCF₃)₂(H₂O)₅]⁺ with terminal coordination of O₂-. The trinuclear acetate [Rh₃(₃-O)(-O₂CCH₃)₆(H₂O)₃]⁺, unlike its trifluoroacetate analog [Rh3(₃-O)(-O₂CCF₃)₆(H₂O)₃]⁺, is oxidized only electrochemically at a potential of 1.38 V. The oxidation of [Rh₃(₃-O)(-O₂CCH₃)₆(H₂O)₃]⁺ is reversible and involves formation of an unstable superoxo group O₂ ^- between two Rh₃III(₃-O) cores.     

Pressure sensitivity of the peak current of gallium arsenide tunnel diodes

The influence of hydrostatic pressure on the peak current of gallium arsenide tunnel diodes is studied in this paper. Analysis of the experimental pressure dependence of the peak current for diodes with different levels of doping in the n region and comparison with the theory served as the basis for finding the size of the energy gap between the absolute and secondary minima at the point X₁ and the velocity of travel of the energy gap with pressure: ⁰=(0.37±0.01) eV; d/dP = –(15±2)·10^–6 eV/bar.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 74–77, September, 1976.     

Stress at alloyed metal contacts with silicon and gallium arsenide

An optical-polarization procedure is described for determining the residual stress at alloyed metal contacts on the primary crystallographic planes of semiconductors. Equations are derived for the birefringence and the angle between the stress and one of the optic axes for various directions of uniaxial stress in {100} and {110} planes. These equations can be used to calculate the mechanical stress in T_d, O, and O_h cubic crystals (43 m, 432, and m3m). The stress has been determined experimentally for the cases of alloyed metal contacts on various crystallographic planes of silicon and gallium arsenide.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No.3, pp. 7–12, March, 1971.In conclusion the authors thank V. F. Konusov and V. I. Nikitenko for consultation and discussion of these results.     

Modeling trajectories and radiation spectra of relativistic particles in crystals. Radiation polarization characteristics

A method is developed for calculation of the polarization characteristics of radiation based on computer tracking of relativistic particle trajectories. The dependence of the Stokes parameter which defines the polarization properties of the radiation upon photon frequency is determined for characteristic trajectories. Formation of full spectra and the degree of linear polarization for averaging over possible trajectories are considered, and results are compared with available experiments.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 63–68, November, 1986.The authors are indebted to S. A. Vorob'ev for his support in the study and evaluation, to M. I. Podgoretskii and A. P. Potyltsyn for their valuable discussion, and to O. V. Boyarko for assistance in formulating the plan of the study.     

Structure and properties of interphase boundaries of gallium arsenide-metal (dielectric)

To study the nature and properties of potential barriers in gallium arsenide devices, we have investigated structural phase transitions in GaAs contacts with multilayer films containing refractory transition-metal borides (TiB₂, LaB₆). We verified the important role in degrading Schottky barrier device performance played by local mechanical stresses introduced at the interface by lateral nonuniformities in interphase interactions. We examine the electrical properties of MIS gallium arsenide devices, taking into account the high density of electronic surface states (ESS). We show it is possible to control the density of ESS by selecting the dielectric, and we discuss its deposition and annealing with a pulsed laser. We discuss the nature of potential barriers in gallium arsenide devices, drawing upon our data and previously published data and modern theoretical models.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, No. 10, pp. 52–62, October, 1993.     

Nonlinear physics and modern technology

Typical systems considered in nonlinear physics are complex dynamics systems in which matter and energy fluxes are accompanied by and controlled by information fluxes. In this paper, we compare two types of complex partially controllable systems: on the one hand, a modern physics laboratory in which processes are investigated in solids (dielectrics, semiconductors, metals, and structures) exposed to high-power pulsed fluxes of photons and massive particles; and on the other hand, an industrial shop using modern technology for applying anticorrosion and protective electrically insulating and chemically resistant coatings on steel pipes for thermal pipelines. The systems to be compared (the physics laboratory and the shop) have much in common from the standpoint of nonlinear physics. This allows us to investigate and optimize the structure of modern production processes and the corresponding production equipment (production lines) by methods of nonlinear physics, and also to show how important it is for students (who will be production equipment designers and process engineers) to spend considerable time doing practical work in a modern experimental physics laboratory. Tomsk Polytechnical University, Tomskénergo OAO [Open Joint-Stock Company]. Institute of Power Electronics, Siberian Branch, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 104–115, November, 1997.     

Effect of electron irradiation on excess currents of GaSb tunnel diodes

Forward biased currents in GaSb tunnel diodes are studied. In the excess current region four segments with differing current transfer mechanisms can be distinguished in the forward branch of the current-voltage curve (CVC) for unirradiated diodes. Irradiation by electrons with energies of 2.2 MeV produces an increase in excess current accompanied by a change in the current transfer mechanisms in the individual segments. The increase in excess current is related to formation and realignment of radiation defects which produce shallow and deep levels in the GaSb forbidden zone. Tunnel spectroscopy with irradiation was used to determine energy levels of E_c-0.060 and E_c –0.2 eV in the n-region of the p-n junction.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 89–93, July, 1984.     

Work function and electrical conductivity of germanium for various crystallographic orientations of the surface

We have studied the contact potential and electrical conductivity as a function of time for thin n- and p-type germanium samples immediately after their preparation; the measurements were made for different orientations of the surface. These results, and field effect studies, indicate the absence of crystallographic anisotropy in the measured quantities. This is explained by the complicated nature of the changes in the work function of the germanium following etching.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 111–116, July, 1972.