Vol 80, No 2 (2016)

Secondary-ion mass spectra and energy distributions upon bombarding a gallium arsenide single crystal using Bi_m⁺(m = 1–5) cluster ions with energies of 2–12 keV are investigated. The gallium cluster ion yield grew nonadditively with the number of atoms in the cluster projectiles. A quasi-thermal component found in the energy spectra of secondary Ga⁺ and Ga₂⁺ ions is indicative of the occurrence of the thermal spike mode upon cluster ion bombardment. The quasi-thermal component in the yield of atomic Ga⁺ ions upon bombardment with Bi₂⁺–Bi₅⁺–ions is 35–75%.

A theory of the ion sputtering of metal in the form of excited neutral and charged clusters with their subsequent fragmentation to the stable state is developed. This theory is based on simple physical assumptions and agrees well with experiments. The results are presented in the form of practical formulas. The overall yields of stable neutral and charged clusters of silver, indium, and niobium are calculated as an example.

Useful analytical approximation formulas for the sheath electric potential profile in the presence of secondary electron emission in oblique magnetic field is suggested.The potential distributions calculated with the proposed model are in good agreement with the respective simulations perfomed with a combined PIC and Monte Carlo code ELECTRAN. The influence of the magnetic field inclination angle on the angular and energy distributions of ions incident on plasma-facing components (PFC) and thus on the effective sputtering yield is analyzed.

Ionic yields from different impurities of pure quartz concentrates are investigated.

The variation in the composition, structure, and properties of CdTe films when bombarded with Ar⁺ ions in combination with annealing is investigated. It is established that the technological treatment makes CdTe film surfaces much smoother and the films become nearly perfect in their stoichiometric composition and properties.

Aspects of the ion modification of the outer surfaces of tubular samples of E110 (Zr–1% Nb) alloy is studied. The samples are irradiated with a radial beam of argon ions (0.5–5.0 keV, (5–10) × 10¹⁸ ion/cm²) on the ILUR-03 setup. It is found that such ion bombardment smooths the relief formed by mechanical abrasive treatment. It is demonstrated that the effect of ion polishing is most pronounced for surface irregularities of a certain size.

Results from structural and morphological studies, measurements of the sheet electrical resistance, and estimating resistivity ρ_m of a graphite-like conducting surface layer formed upon high-dose irradiation of the (111) face of a synthetic diamond with Ar⁺ ions at an energy of 30 keV and a target temperature of 400°C are presented. It is found that the orienting effect of the diamond lattice is visible in the suppression of the formation of graphite crystallites with axis c perpendicular to the surface. The thickness of the modified layer is 40–50 nm, and its sheet resistance is 0.5 kΩ/sq. Resistivity ρ_m = 20–25 μΩ m of the modified layer lies within the range of ρ values of graphite and glassy carbon materials.

The dependence describing the probability of the electron excitation of a crystal by the energy of a chemical reaction on the energy of electron transitions is derived. It is found that the probability of electron chemoexcitation grows exponentially when the energy of electron transitions falls in the solid state. The efficiency of the nonadiabatic chemo-electronic conversion of energy in structures of hydrogen energetics based on Schottky diodes is calculated.

Parameters of inductively coupled plasma (ICP) discharges in a mixture of gases N₂, H₂, and Ar at a total pressure of 1.5 × 10^–3 mbar and a partial pressure ratio N₂: H₂: Ar = 2: 12: 1 are discussed. The plasma properties are analyzed using Langmuir probes and optical emission spectroscopy. The ICP discharge is used for the nitriding of specimens made of Russian grade 30ChGSA structural steel. The nitriding experiments are performed at different bias voltages V_b in the range of–200 V to +100 V with respect to the walls of the discharge chamber. The surface hardness of the treated specimens depends substantially on the bias voltage, being much higher than the initial value in all cases. The obtained results demonstrate the possibility of increasing the surface hardness up to 1000 HV (4–5 times the initial values) at the bias voltage equal to the floating potential.

The processes of establishing of generalized chaotic synchronization in a network of mutually coupled continuous-time systems are investigated. The nature of interaction between the network elements in transitioning from synchronous to asynchronous behavior while increasing the communication parameter is studied. A synchronization regime, the nearest neighbors method, and calculations of the spectrum of Lyapunov exponents are used to clarify features of the interaction between network elements and the occurrence of a generalized chaotic.

Issues related to possible mechanisms of the generation of wind-formed extreme waves in the ocean and their forecasting are considered. Data on the generation of solitary waves in a ring wind-and-water tunnel are presented.

The possibility of experimentally obtaining backward collinear isotropic acousto-optic interaction based on bulk ultrasonic waves and terahertz electromagnetic waves is considered. The magnitudes of the acousto-optic figure of merit and the corresponding acoustic frequencies are calculated for the basic crystallographic axes in germanium and iodic acid crystals. The acousto-optic parameters of both crystals are compared.

The nonstationary reflection of an electromagnetic impulse off a highly reflective load matched to a waveguide is investigated theoretically and experimentally. The results from numerical simulations, obtained using a finite difference time domain and experimental data, are presented. The studies are performed in the frequency domain of 8.5 to 12 GHz.