Sergey D. Zotov

Resonant IR laser-induced diffusion of oxygen in silicon

B.H.Makeev**,I.F.Mogilnik*, V.N.Pavlovich*, B.N.Romanuk***, V.I.Soroka*, V.V.Tokarevski*, S.D. Zotov***4nstitute for Nuclear Research, Kiev, USSR; **.Lebedev Physical Institute, 53 Leninsky pr.,117924 MoscowUSSR; ***Jnstjtute of Semiconductors, Kiev, USSRABSTRACTThe analysis of experimental data on resonant IR laser-induced diffusion of oxygen in silicon are presented in thiswork.Resonant irradiation leads to the increase of oxygen diffusion coefficient which corresponds to increase of effectivetemperature of the crystal approximately by three times. The control experiments included changing of laser emission

Sound velocity vl and vl/4 solitonlike wave components observation in ZnS excited by high-power IR laser pulse

Wave of Change of Reflection and Conduction (WCRC) is the new reversible IR laser induced phenomenon, which can present solitonic mechanism of heat transfer in solids. WCRC appears in answer to one exciting pulse as the consequence of the following each another pulses (wave-components) and could be important in many laser-surface interactions. One of the most interesting features of WCRC is the observed discrete (in 2 times) change of the velocity of each following component. Present work gives one more experimental proof of this statement.

Experimental study of visible reflection variation from high-temperature superconductor ceramics as a result of irradiation by excimer lasers

The present study started on the basis of a suggestion concerning possible structural modification of HT SC by means of laser irradiation with a frequency close to or in resonance with vibrational or electronic bonds of lattice. The research started in P. N. Lebedev Physical Institute in the frame of the program of IR-laser irradiation of HT SC using an unic 16 - 18 micrometers ED GDL CO2 laser, developed in this institute. An investigation of UV wavelengths effect on these ceramics was fulfilled with use of the high power excimer lasers facility of Marseille IMFM New Lasers Group. We report here on preliminary experiments related to reflectivity change of polarized He-Ne laser beam at Brewster angle in the cases of super conducting and non-super conducting ceramic oxides following excitation by ArF (193 nm) and XeCl (308 nm) excimer lasers for conditions below the ablation threshold.

Slow discrete velocity components of solitonic wave of change in reflection and conduction excited by CO2 laser pulse in Plexiglas and copper foil: experiments with thermocouple as detector

The experimental researches on excitation in Plexiglas of slow components of a solitonic-type Wave of change of reflection and conductivity (WCRC) are continued. Such discrete velocity excitations by a pulse of the CO2 laser (as first for ceramic HT SC samples) were found out by us in 1992. The results of soliton study in experiments with the various real condensed materials represent fundamental interest. We undertook the experiments with the use of the thermocouple as the detector with the purpose of increase of reliability of results received earlier by other methods, especially in relation to the sign of parameter variation in WCRC. Thus the assumption proves to be true stated by us before, that the arrival of a studied in Plexiglas results in local decreasing of temperature. The records of thermal processes in a copper foil sample for times in hundreds seconds after a stimulating pulse have allowed to register repeated passage through the foil several WCRC components with velocity of the order of μ/s. It is 104 times slower speed than in the first experiments of 1992.

Experimental data about the sign of local parameter variations in the solitary wave of change of reflection and conduction (WCRC) traveling through different condensed matter

Unusual solitonic-type excitations were found by our group in 1992. As it was shown since that time this waves travel trough different condensed matter with discrete velocities in the range of 9 orders of value (between km/s and less then μs). These waves can carry heat or cold as it can be seen from the sign of local parameters variation. Explanation to this facts one can find in suggestion that this waves could be as compression as expansion ones (the physical mechanism of all phenomenon not known yet). This work contains short review of experimental results, which show characteristically sign variation for different materials. This work was sponsored as projects 00-02-17249-(a) and 02-02-26611-(3) by RFBR, its presentation - by SPIE and KIE.

Slow components of solitonic wave of change in reflection and conduction excited by CO2 laser pulse in plexiglass: experiments with IR detector

Experimental results of investigation in plexiglas support previously published our groups data of JR laser and e-beam excitation in solids of solitonic Wave of Change in Reflection and Conduction (WCRC). Method of single IR detector WCRC registration was applied in addition to JR thermovision method used before (there were used also -5other different methods). Results of slow WCRC components investigations showed that solitonic heat transfer play additional role to usual diffusive heat transfer. This role could be important at some conditions. As the control, the measured in this work WCRC component velocity ~ 0.26 cm/s does not depend from sample thickness which was equal 1.5 and 2.0 mm. Analysis of records treatment by help of (x-t) diagram permit to show many features of studied solitonic excitations lived in the solid sample during many minutes. Irradiation of the front surface by single laser pulse produced WCRC components; in experimental conditions of this work one can see pair components of the same velocity which were born as on front as on rear sample surface. They moved in different directions and reflects from sample surfaces many times with small energy losses. This work was sponsored by RFBR (Russia), project 97-02-17954-a) and 00-02-17249 a).

Development of phase analysis method of high-temperature superconductor YBaCuO by its Raman spectrum

Some modification of the YBaCuO phase analysis method using the Raman spectra is proposed. It is based not only on the analysis of the corresponding Raman band maxim positions, as usually, but on the analysis of the integral contours of these bands as well. The 400-500 cm-1 region of Raman spectra of the YBaCuO single crystals was studied for this purpose. The proposed method was realized in original PC-program, which allows fulfilling an express, non- destructive and local phase control for HT SC samples.

Dislocation migration activation energies for HTSC ceramics from temperature dependence of the solitonic wave of change in reflection and conduction

Abstract The dislocation migration activation energies, E dm , were estimated based on the comparison of a model and experimental results for velocity temperature dependence of wave of change of reflection and conduction, a new heat transport phenomenon. These values E dm are the as follows: 0.001eV; 0.02eV; 0.04eV for YBaCuO, NdCeCuO, LaSrCuO and 0.002eV for Ge single crystal, respectively.

Laser-induced slow wave of reflection and conduction change in solids: experimental and theoretical study of the solitonic mechanism

Solitonic propagation of IR laser pulse-induced wave of reflection and conduction change is investigated experimentally and theoretically. The temperature dependence of the wave velocity in Ge and high temperature superconductive ceramics is shown to be semiquantitatively described by the theory of slow defect recombination wave.

Temperature dependence of the wave of reflection and conduction excited in semiconductors Ge, ZnS, and ZnSe

Temperature velocity dependence of the wave of reflection and conduction (WRC) excited by pulse of CO2 laser in semiconductors ZnS, ZnSe, Ge, was studied by optical methods. Such data are needed for the adequate WRC mechanism development.