Optical gap of silicon crystallites embedded in various wide-band amorphous matrices: role of environment.

Within the framework of the envelope-function approximation the single-particle and the optical gaps of silicon nanocrystals embedded in amorphous SiO(2), Si(3)N(4), Al(2)O(3) and ZrO(2) dielectric matrices were calculated. We employ the model of an Si quantum dot surrounded by a spherical thin intermediate layer with a radially varying permittivity, separating the nanocrystal and the host dielectric matrix. The latter was modelled by the finite-height potential barriers.

Improvement of the photon generation efficiency in phosphorus-doped silicon nanocrystals: Γ-X mixing of the confined electron states.

It has been shown that the central-cell potential of a phosphorus ion embedded in a silicon nanocrystal effectively mixes the electronic states of X- and Γ-bands. Quantum confinement strengthens the Γ-X mixing which, in turn, straightens the nanocrystal's band structure, and substantially intensifies interband radiative recombination.

The nonlinear decay of complex signals in dissipative media.

The solution of Burgers' equation with random initial conditions is often said to describe "Burgers turbulence." The Burgers equation describes two fundamental effects characteristic of any turbulence-the nonlinear transfer of energy over the spectrum and the dissipation of energy in the small-scale components. Strong interaction between coherent harmonics, associated with the nondispersive nature of the dynamics, leads to the appearance of local self-similar structure.

The kinetics of liquid-gas phase transitions of a Van der Waals substance with fluctuations taken into account.

The isotherm of a Van der Waals substance, containing only stable points, is obtained on the basis of using the thermodynamic potential for nonequilibrium states and taking fluctuations into account. It is shown that in the vicinity of two-phase states this isotherm is close to the horizontal phase equilibrium line, defined by Maxwell's rule. The lifetimes of the metastable states of the Van der Waals substance, which depend on the intensity of the external fluctuations and the number of particles in the system, are estimated.