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 QD lasers is
generalized for the case of multiple radiative transitions.
The effect of microscopic parameters on the gain is
discussed. The conditions for a smooth or step-like change
in the lasing wavelength with the losses are formulated.
Threshold characteristics of a laser based on self-assembled
pyramidal InAs QDs in GaAs matrix are simulated. A small
overlap integral for optical transitions in such QDs (and
hence large spontaneous radiative lifetime) is shown to be a
main possible reason for a low value of the modal gain of
the respective structure, which is deficient to attain
lasing at moderately short (several hundreds of micrometers)
cavity lengths.
Theory of multimode generation caused by the effect of
spatial hole burning in QD lasers is generalized for low
temperatures. The multimode generation threshold is shown
to be controlled by the spontaneous lifetime in QDs and is
essentially temperature-independent (in contrast to high-
temperature regime when it is controlled by the nonvanishing
times of thermally excited escapes of carriers from QDs and
depends exponentially on the temperature). Ways to optimize
the QD laser, aimed at maximizing the multimode generation
threshold, are outlined.
Theoretical analysis of carrier photoexcitation from levels
in QDs to continuous-spectrum states during the laser
operation is given. The light absorption in the process of
carrier photoexcitation is shown to be essential in the
quantum dot laser operation only at very low total losses,
e.g., for the case of long-cavities.
Simple variational function, well deckribing X+ and X-
trions in two-dimension quantum well, is found.
We have continued the theoretical investigation of kinetic
properties of carriers in Quantum Dot Superlattices of
various dimesionality (1D, 2D, 3D QDSL). The qualitative
analysis of the dependence 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 dephasing of Bloch oscillations is
few degrees of magnitude slower than that for quantum well
superlattices. Such a small dephasing time opens a
possibility of observation and practical usage of Bloch
oscillations at the enviropment temperature.
The wave functions of carriers in quantum wells with the
existence of the transversal magnetic field were found in
the framework of the 4-band Kane model. The temperature and
magnetic field dependences of Auger coefficient in such
systems were studied. The wave functions of carriers in
cylindrical quantum wires and spherical quantum dots were
found in the framework of the 4-band Kane model. The
dependences of Auger coefficient in quantum dots on
the temperature, heights of heteroboundaries and radius
were studied.
The investigations of defect evolution in silicon carbide
under Al and N ion irradiation has been carried our taking
into account stress field due to different clusters of
radiation defects.
2.7. A.F. Ioffe Physico-Technical Institute of Russian Academy of
Sciences