Skobeltsyn Institute of Nuclear Physics
Lomonosov Moscow State University

Laboratory of plasma physics and basis of microtechnology

The Laboratory of plasma physics and basis of microtechnoloy (LPPBMT) is headed by Professor, DSc. Alexander Rakhimov.

The Laboratory consists of the leading scientific school "Experimental and theoretical studies of non-equilibrium plasma processes in the gaseous phase and on the surfaces" under the leadership of Professor Rakhimov. Development of the team was initiated by the Academician Evegeny Velikhov due to the beginning of the development and production of powerful gas-phase lasers. This research resulted in the dscovery and explanation of physical mechanism of a number of disequilibriums which are in progress both in plasma volume and in near-electrode regions.

During the studies of electric-discharge pumping of gas-phase lasers it was shown that elementary plasma-chemical reactions in gaseous phase and heterogeneous reactions influense actively on electrodynamical characteristics of discharges and change composition of low-temperature plasma significantly due to super-equilibrium running of chemically active radiacals. Studies in this field activated beginning of a new research associated with using of electrical discharges as plasma-chamical reactors. Obtained results produced a basis for the development of a new direction of plasma methods intended for the solution of a number of problems in vacuum electronics and microtechnology.

Research field of the scientific school.

Physics and kinetics of low-temperature plasma of gaseous discharges. Elementary processes in the gaseous phase and on the surface of solid objects. The studies of the growth and electrophysical properties of thin films precipitated from the gaseous phase on the surfaces by plasma methods.

Stationary and non-stationary discharges of direct current, HF and microwave discharges in different gaseous mixtures were studied during the recent decade. The role of near-electrode layers, volume and near-electrode disequilibriums were analyzed. New types of glow discharge, i.e. non-self maintained discharge and barrier discharge in glow mode were implemented and studied. Studies of stationary and impulse discharges with escaping electrons were carried out. Wide range of research in the field of volume and surface plasma chemistry was conducted. Radiating properties of neutral gases plasma, neutral gases mixtures and halogen-containing molecules and metal vapors were studied.

Obtained results were implemented in the following applications:
● Gas-discharge lasers.
● Ozone and singlet oxygen generators.
● Plasma etching reactors.
● Plasma reactors for new nano-structured materials production.
● Plasma light sources in different spectral ranges.
● Plasma displays.

Directions of current research of the scientific school.
Currently research within the frames of the scientific school are focused on experimental and theoretical studies of elctrodynamics and plasma-chamical kinetics in compleх gaseous mixtures. The activity of the research team is characterized with strong interrelation between experimental and theoretical studies.

The basic direction of the research during the recent years:
● Non-equilibrium elementary processes in plasma volume and during its interaction with the surface applied to the processes of precipitation, etching, polymerization processes, to the processes in ion-ion and dust plasma, to the processes of particles' coagulation in plasma, growth of hydrocarbons' and fluorocarbons' clasters.
● Optimization of plasma processes in the mode of high specific energy inputs in order to prioduce gas-discharge lasers in new media.
● Optimization of plasma processes for new light sources with high efficiency and brightness.
● Studies and development of new discharge schemes for plasma microtechnology.
● Studies of elementary processes in strong laser fields of femtosecond duration.
● Studies of ion-molecular input into the process of heterogeneous phase in the plane fuel combustion stream.

Recently the following results were obtained by the scientists of the school:
● Excitation efficiency in excimer lamps based on impulse spark discharges was studied.
● Excitation efficiency of plasma displays depending on power supply impulses frequency was studied. Influence of the effects electron spectrum non-locality on plasma display discharge structure was analyzed.
● Effects of electron spectrum non-locality on electronegative gas was experimentally studied for the first time.
● Kinetics of fluorocarbon production and mechanisms of their polymerization were studied by method of laser-induced fluorescence in order to explore the processes in the etching reactor.
● Excitation effeciency of helicon plasma with different types of antennas was studied.
● Distinctive features of a new object of ion-ion plasma production in impulse-periodic discharges of electro-negative gases were explored.
● New mechanisms of oxygen electron-excited states quenching were experimentally found and theoretically explained.
● Processes in the dust plasma were studied. Influence of electrons' scattering on the dust particles on energy distribution of electrons was analyzed. Mechanism of electrons' recombination in the dust plasma of non-self maintained discharge and mechanism of coagulation of dust particles in plasma were explored.
● A number of elementary processes in strong fs laser fields was studied. Numeric methods of analysis of ionization dynamics of simplest two-electron systems by electromagnetic wave field have shown an important role of energy exchange of the electrons. Ionization process and structure of energy spectrum of quantum system with short-range potential in the strong electromagnetic environment were studied. Process of one- and two-electron ionization of di-atomic molecule was explored, channels of ots fragmentation in the strong radiation field were analyzed. Basic channels of molecules fragmentation were discovered and spectra of the ions produced by ionization and dissociation of di-atomic molecule in the strong laser field were determined. Non-linear properties of the environment appeared due to molecules orientation effects were analyzed.
● Physical-chameical properties of sooty aerosoles imitated by jet engine of the plane were studied in order to determine possible chemical and climate consequences of aviation influence of the atmospere. Input of ion-molecular reactions to the mechanism of condensed phase production in the stream of plane fuel combustion and its influence. In collaboration with CRMC2 Laboratory of Marseille University a cycle of studies of water absorption and dymanics at low temperature was carried out. Obtained unique results have shown that sooty aerosoles could become centers of ice nucleation keeping part of water in liquid state to the temperature of the low stratosphere ≈ 200К.
● Kinetics of the processes in deposiion reactors (basing of the discharge: direct current, HF, SHF, plasmotrone and in the reactor with hot filament) during production of hydrocarbon films of different structures was analysed. Mechnaisms of basic radicals production and destruction were determined, hydrocarbons' conversion was studied, precursors of films growth were defined. SHF and hot filament reactors were scaled in order to produce homogeneous nano-carbon coatings on the base up to 300 sm² area.
● Thin carbon films structure and their emission properties were explored.
● Wide-aperture sources of UF and VUF emission were suggested and realized.
● Prototype of miniature ozon generator was developed basing on an original scheme of barrier discharge.
● Bright (> 20000 Cd/m^{2) and effective (> 30 Lm/W) emitting screens basing on excitation of phosphor by running electrons are developed and produced.}