2.1.    99-02-16796
2.2.    Suris Robert Arnol'dovich
2.3.    Theoretical investigations of the electronic and optical
        properties and the processes of growth of semiconductor
        heterostructures with quantum dots and strained quantum 
        wells.
2.4.    2001
2.5.    2
2.6     Theory of threshold characteristics of quantum dot (QD)
        lasers was created.

        The critical tolerable parameters of the QD structure (QD
        size dispersion, their surface density and the cavity
        length) behind which the lasing generation is impossible
        to attain have been shown to exist. The threshold current
        density increases infinitely and the relative multimode
        generation threshold approaches zero as the parameter
        tends to its critical tolerable value.

        The effect of spatial hole burning in the population
        inversion in QDs has been shown to be very important in
        QD lasers (in contrast to quantum well lasers). The
        multimode generation threshold in QD lasers due to this
        effect is calculated as a function of QD size dispersion
        and temperature. Ways to optimize the QD laser, aimed at
        maximizing the multimode generation threshold, are
        outlined.

        Theory of threshold characteristics of QD lasers is
        generalized for the case of multiple radiative
        transitions, the role of carriers photoexitation from QD
        levels to continuous spectra has been investigated.

        A small overlap integral for optical transitions is shown
        to be a main possible reason for a low value of the modal
        gain of lasers based on self-assembled pyramidal InAs QDs
        in GaAs matrix, which is deficient to attain lasing at
        moderately short (several hundreds of micrometers) cavity
        lengths.

        We have shown that spectrum of electrons in ideal 2D and
        3D quantum dot superlatices (QDSL) in homogenious dc
        electric field can be discrete or continuos depending on
        the field orientation. In the last case the width of
        appearing miniband exponentially depends on field
        direction.

        The Bloch oscillations in 2D and 3D QDSL have been
        studied. Analysis of dependences of phase relaxation time
        of Bloch oscillating electrons on the dc electric field
        strength and orientation and on the values of resonant
        tunneling matrix elements among quantum dots have been
        developed. We have found the conditions when at room
        temperature dephasing of Bloch oscillations is few
        degrees of magnitude slower than that for quantum well
        superlattices.

        Rates of Auger recombination in quantum wires, quantum
        dots and in quantum wells in magnetic field were
        obtained. Influence of many-particle relaxation processes
        on rates of radiative and Auger recombination in quantum
        sized heterostructures was investigated. Two novel types
        of optoelectronic devices, namely, Auger-laser on
        subband-subband transitions and laser with active region
        cooled by injection current, were proposed.

        The binding energies of the singlet and the triplet state
        of two-dimensional X+ and X- trions is calculated at all
        values of the electron-to hole mass ratio with a simple
        variational function. The critical value of the mass
        ratio is found for the triplet state of X+ trion. The
        behavior of the trion binding energy has been examined
        analytically near the critical mass ratio.

        The investigations of defect structure in silicon carbide
        under Al and N ion irradiation at different temperatures,
        as well as during annealing of irradiated samples. The
        estimations of displacement threshold energies in Si and
        GaAs have been made.

        It is shown, that  correct modeling of wavy-shaped step
        structures on vicinal surfaces during epitaxial growth or
        etching could be achieved only via taking in account
        second neighour interacting. We found the set of model
        parameteres controlling processes of patterning crystall
        surface.

        We demonstrate that at low supersaturations mean
        concentration approximation incorrectly describes
        condensed phase nucleation from the vapour of diffusing
        monomers. In this case characteristic drops of
        supersaturation due to monomers capture by growing nuclei
        exceed the value needed to "switch off" nucleation. We
        propose a simple model correctly describing nucleation in
        this case.

2.7.    A.F. Ioffe Physico-Technical Institute of Russian Academy of 
        Sciences