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