Maskless structuring of the surface of silicon substrates for nitride epitaxy
Maskless structuring of the surface of silicon substrates for nitride epitaxy
M.G. Mynbaeva, S.P. Lebedev, A.A. Lavrent'ev, K.D. Mynbaev, V.I. Nikolaev
A self-structuring of the surface of silicon wafers under specific annealing conditions is reported on. This effect can be used for developing new maskless methods of the fabrication of structured silicon substrates, which are prospective for the use in the technology of light-emitting diodes based on gallium nitride and III–nitride solid solutions.
Show AbstractCharacterization of GaN and GaN based structures by scanning electron microscopy methods
Characterization of GaN and GaN based structures by scanning electron microscopy methods
Yakimov E.B.
Results demonstrating possibilities of scanning electron microscopy methods for a characterization of GaN and GaN based light emitting structures are presented. Methods for correct excess carrier diffusion length measurementы in the structures with the small diffusion length are discussed. It is shown that the Electron Beam Induced Current (EBIC) method allows not only to measure the diffusion length in GaN films but in some cases to reconstruct also the lateral donor center distribution with a spatial resolution in the micrometer range. It is shown experimentally that in the structures with the small diffusion length the lateral resolution under extended defects revealing can be about 100 nm or even better. It is shown that channels of enhanced minority carrier transport across the active region of light emitting structures with InGaN/GaN quantum wells can be revealed by the EBIC.
Show AbstractHybrid state of Tamm and surface plasmon-polaritons in one-dimensional photonic crystals
Hybrid state of Tamm and surface plasmon-polaritons in one-dimensional photonic crystals
V.O. Bessonov, I.V. Soboleva, B.I. Afinogenov, D.N. Gulkin, D.A. Shilkin, A.T. Le, and A.A. Fedyanin
Hybrid mode of Tamm plasmon-polariton and surface plasmon-polariton in 1D photonic crystal/semitransparent metal film is experimentally observed. The hybrid state is excited under conditions of total internal reflection for TM-polarized light. Spectral and angular dependences of the hybrid mode resonances positions are studied in the Kretschmann geometry by the methods of frequency-angular spectroscopy. Coupling between Tamm and surface plasmon-polaritons leads to repulsion of their dispersion curves controlled by metal film thickness. Experimental results are in a good agreement with the numerical calculations.
Show AbstractInfluence of heating the surface of the particle on photophoresis of large aerosol particle at high temperature differences in its surroundings
Influence of heating the surface of the particle on photophoresis of large aerosol particle at high temperature differences in its surroundings
A.V. Limanskaya
In the Stokes approximation the photophoretic motion of large solid aerosol spherical particle is described theoretically. By consideration of the motion assumed that average temperature of the particle surface significantly differs from the temperature of gaseous medium. During solution process of gas-dynamic equations analytical expressions for the force and velocity of photophoresis obtained taken into account the dependence of gaseous medium density and viscosity and heat conduction on temperature .
Show AbstractGravitational radiation from a charge in electromagnetic field
Gravitational radiation from a charge in electromagnetic field
Yu.V. Grats
It is shown that in the Furry representation matrix element for a graviton emission by an electron in the field of a plane electromagnetic wave is proportional to the matrix element for the emission of a photon. The proportionality coefficient is a pure classical and depends on the direction of graviton propagation only. Possibility to transfer the results for the case of an arbitrary external electromagnetic field is discussed.
Show AbstractFemtosecond dynamics of surface plasmons in one-dimensional plasmonic crystals: frequency-resolved optical gating (FROG)
Femtosecond dynamics of surface plasmons in one-dimensional plasmonic crystals: frequency-resolved optical gating (FROG)
V. V. Zubyuk, A. I. Musorin, P. P. Vabishchevich, M. R. Shcherbakov, M. I. Sharipova, A. S. Shorokhov, T. V. Dolgova, A. A. Fedyanin
Changes in the temporal profile of the electromagnetic field of a femtosecond pulse at the resonant excitation of plasmon-polaritons (PP) in the vicinity of the band gap edges of plasmonic crystal were demonstrated using the frequency-resolving optical gating (FROG) technique. It is shown that the broadening of the p-polarized pulse reflected from the plasmonic crystal is 20% more than in the case of s-polarized light in the vicinity of band gap edges where the lifetime of plasmon-polaritons is highest. The spectrum of the reflected pulse is significantly modified because of the resonant excitation of the PP in the crystal — the intensity decreases near the wavelengths corresponding to the band gap edges.
Show AbstractUltrafast dynamics of third harmonic generation in fishnet metamaterials
Ultrafast dynamics of third harmonic generation in fishnet metamaterials
A.S. Shorokhov, K.I. Okhlopkov, D.V. Chichinadze, M.R. Shcherbakov, A.A. Fedyanin
Ultrafast temporal evolution of the third harmonic generated by a fishnet metamaterial was studied using the pump-probe technique. The experimental data indicate the existence of a delay in the nonlinear response of the metamaterial. The delay is attributed to the ultrafast relaxation processes in gold characterized by a time constant of 1 ps that is comparable to the electron-phonon relaxation time.
Show AbstractTwo-gap superconductivity of doped mercury cuprates
Two-gap superconductivity of doped mercury cuprates
S.V. Kulbachinskii, Ya.G. Ponomarev, I.M. Slobodchikov, L.M. Fisher
The results of Andreev spectroscopy studies show that in mercury cuprates Hg-1201 (sigle-layer phase) and Hg-1212 (two-layer phase) superconductivity has a single-gap character. Qualitatively different results were obtained for a three-layer phase Hg-1223. In slightly overdoped polycrystalline samples Hg-1223 (Tc = 124 ± 5 K) two superconducting gaps were observed corresponding to one internal (IP) and two outer (OP) CuO2 – planes. The existence of multigap superconductivity in mercury cuprates HgBa2Can-1Cun02n +2 + δ with n ≥ 3 is explained by the difference in doping levels of external (OP) and internal (IP) CuO2 - planes.
Show AbstractElectromagnetic excitation of longitudinal and shear ultrasonic waves in thin films of yttrium iron garnet
Electromagnetic excitation of longitudinal and shear ultrasonic waves in thin films of yttrium iron garnet
I.E. Gospodchikova, V.M. Sarnatsky
The influence of geometrical dimensions of the yttrium-iron garnet plate (thickness), geometry and intensity of applied bias and alternating magnetic fields on the efficiency of ultrasound generation is researched. Experiments revealed resonant-dimensional effects, which cannot be described in terms of existing theory. A hypothesis of involvement of domain borders oscillations into ultrasound generation is suggested.
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