Carbon saturation of silicon target under the action of pulsed high-intensity ion beam

The action of the pulsed high-intensity ion (carbon) beam on the silicon target is investigated by means of the theoretical model. The forming of the carbon concentration profile in depth of the silicon sample is modelled. It is argued, that there are two ways of the profile forming: short-pulsed ion (carbon) implantation and diffusion of the carbon atoms adsorbed on the silicon surface. It is shown, that the carbon atoms adsorbed on the silicon surface and diffused into the silicon target play the main role in the concentration profile forming

Modelling of chemical reactions in plasma

The paper is devoted to theoretical investigation of interaction of pulsed high current electron beam with gas substance. As a result of the interaction the formation of chemical active plasma can be observed. One of the key parameter for theoretical analyze of the process is the electron distribution function. Within the framework of the Boltzmann approach we obtained the dynamical equation for electron distribution function depending on the electron energy, coordinate and time

Study of plasma formation in a planar type ion diode with self-magnetic isolation

One of the sources of high-power ion beams is an ion diode with isolation by external or self-magnetic field. Due to the simplicity and reliability of the design, this type of diodes is widely used in applied research. The explosive plasma generation on the anode surface under a bipolar voltage pulse is accompanied by a loss of the electron current from the anode-cathode region of the diode. The electron current characteristics depending on the operation mode of diode and the energy supplied are presented. Investigation of the cathode emission surface and distribution of the ion current density at the output of the diode along the anode surface were carried out. The ion current density reaches 15-25 A/cm2 at the outer edge of the anode, and 5-8 A/cm2 – in the central region. The area of emission surface of the anode is approximately 25-30% of the total anode area. Electron loss current in the matching mode of diode reaches 6.5 kA

The Influence of High-Power Ion Beams and High-Intensity Short-Pulse Implantation of Ions on the Properties of Ceramic Silicon Carbide

The paper is focused on the study of the structural, electrical and optical characteristics of the ceramic silicon carbide before and after irradiation in the regimes of the high-power ion beams (HPIB) and high-intensity short-pulse implantation (HISPI) of carbon ions. The dominant mechanism of transport of charge carriers, their type and the energy spectrum of localized states (LS) of defects determining the properties of SiC were established. Electrical and optical characteristics of ceramic before and after irradiation are determined by the biographical and radiation defects whose band gap (BG) energy levels have a continuous energetic distribution. A dominant p-type activation component of conduction with participation of shallow acceptor levels 0.05-0.16 eV is complemented by hopping mechanism of conduction involving the defects LS with a density of 1.2T0{17}-2.4T0{18} eV{-}Am{-3} distributed near the Fermi level.The effect of radiation defects with deep levels in the BG on properties change dominates after HISPI. A new material with the changed electronic structure and properties is formed in the near surface layer of SiC after the impact of the HPIB

The Effect of Doping on the Electrophysical Properties of Polycrystalline Diamond Films Deposited from an Abnormal Glow Discharge

The paper is focused on the study of the boron doping effect on the electrical characteristics, on the mechanism of charge carrier transfer, and on the energy spectrum of the localized defect states in the polycrystalline diamond films (PDF) deposited from an abnormal glow discharge. PDF doping enables to form the semiconductor layers of p-type conductivity, which have as good properties as those of PDF produced by the alternative methods. The doping reduces the degree of disorder in the film material brought by the growth defects, which determine the film electrical characteristics and electrotransfer mechanism. The PDF electrical characteristics and electrotransfer mechanism are determined by the defects of different nature, whose band gap energy levels have a continuous energy distribution. A p-type activation component is realized in the exchange of charge carriers between the valence band and shallow acceptor levels with the activation energy of 0.013-0.022 eV. Doping increases the effect of the hopping mechanism of the conductivity involving the localized states with a density of (1-6)•10{20} eV{-1}•cm{-3} distributed near the Fermi level, which is in the low half of the band gap

Propagation of the pulsed electron beam of nanosecond duration in gas composition of high pressure

This paper presents the results of the investigation of the propagation of an electron beam in the high-pressure gas compositions (50, 300, and 760 Torr): sulfur hexafluoride and hydrogen, sulfur hexafluoride and nitrogen, sulfur hexafluoride and argon. The experiments have been performed using the TEA-500 laboratory accelerator. The main parameters of the accelerator are as follows: an accelerating voltage of 500 kV; an electron beam current of 10 kA; a pulse width at half maximum of 60 ns; a pulse energy of 200 J; a pulse repetition rate of up to 5 pulses per second, a beam diameter of 5 cm. The pulsed electron beam was injected into a 55 cm metal drift tube. The drift tube is equipped with three reverse-current shunts with simultaneous detecting of signals. The obtained results of the investigation make it possible to conclude that the picture of the processes occurring in the interaction of an electron beam in the high-pressure gas compositions is different from that observed in the propagation of the electron beam in the low-pressure gas compositions (1 Torr)

Electrophysical properties of polycrystalline diamond films deposited from an abnormal glow discharge

Electrophysical properties of polycrystalline diamond films (PDF), deposited from the abnormal glow discharge, were obtained. The energetic and kinetic characteristics of surface dark and photoconductivity of PDF and their temperature, field and spectral dependences were investigated. Dominant carrier transport mechanisms, their type and the energetic spectrum of localized defect states were established. Current-voltage characteristics, photosensitivity and activation energy are determined by conductivity of PDF, which varies from 10{-14} to 10{-4} S depending on deposition conditions. Vacuum annealing of films up to 600-800 K stabilizes the electrical characteristics. Thermal stability of PDF properties higher than semiconductor films, deposited under nonequilibrium conditions by pulsed laser and ion ablation. PDF films not inferior on properties to films, obtained by alternative CVD methods. Electrical characteristics, mechanism of charge transport of PDF were caused by defects of different nature, the energetic levels of which are continuously distributed on energy in the band gap. Dominant n-type of activation conduction is complemented by hopping mechanism through the localized states distributed near the Fermi level with density 5.6x10{17}-2.1x10{21} eV{-1} cm{-3}. Trapping and recombination centers are heterogeneously distributed on grain boundaries

Nonequilibrium plasmachemical processes - the basis of future plasma technologies

Laws of molecule excitation in basic electronic condition have been considered. It was shown that nonequilibrium excitation of oscillatory degrees of molecule freedom was the most effective for initiation of chemical reactions. Plasmachemical processes proceeding in such conditions have a number of advantages allowing at their use in traditional manufactures decreasing power inputs and increasing productivity. Conditions realized at pulse excitation of gas mixes are also favorable for organizing chain chemical processes. Experimental data of chain chemical process realization in plasma of pulse electronic beam were presented. Other perspective plasma technologies - pulse radiolysis of liquid phase hydrocarbons at low temperature in conditions of electronic beam influence with high current density,initiation of carbon-black formation process in nonequilibrium conditions were also considere

Synthesis of Polycrystalline Diamond Films in Abnormal Glow Discharge and their Properties

The optical and electrophysical properties of polycrystalline diamond films (PDF) deposited from the abnormal glow discharge have been studied. The dominating mechanisms of absorption and charge carrier transfer and the energy spectrum of the localized states (LS) of defects which determine the properties of the films have been specified. The parameters of the interband absorption and electrical conductivity are determined by the continuous energy distribution in the band gap (BG) of the states of defects of different nature. The absorption edge of the crystalline phase of the films is separated from the absorption zone determined by the electron transitions between LS defects. The width of BG is narrowed to 0.2-0.5 eV from the quantity typical to the diamond. An additional film absorption edge is formed in the energy interval 1.2-3.3 eV, where Urbach rule is fulfilled and the interband absorption is realized at direct transitions through the optical gap 1.1-1.5 eV. The average width of BG is 2.6-3.24 eV estimated within semiclassical interband model. The interaction of the parameters of the interband and exponential absorption is determined by the crystal lattice static disorder. The dominating n-type of the activation component of the electrical conductivity is complemented by the hopping mechanism with the participation of the localized states of the defects distributed near the Fermi level with a density 5.6•10{17}-2.1•10{21} eV{-1}•cm{-3}

Development of technology and investigation of structure and properties of composites on the basis of shungit and polymer resins

The technology for manufacturing of composites based on polymer (epoxy) resins and shungites was developed by using of the electron irradiation and experienced samples with different percentages of the components a) 90 and 10 %, b) 70 and 30 %, c) 50 and 50 %, were manufactured respectively. It was carried out the series of experimental studies of the structure and properties of the obtained materials, including the atomic force microscope images were obtained and Raman spectra of these composites were measured and their analysis was per-formed