StatusThe thesis was presented on the 25 May, 2010
Approved by NCAA on the 5 July, 2010
Abstract– 0.73 Mb / in russian
– 0.72 Mb / in romanian
The management of transport properties in nanostructures using the phonon engineering methods”, PhD thesis, Chisinau, 2010. Introduction, four parts, conclusions, 68 references, 115 pages, 69 figures. The main results of thesis are summarized in 46 scientific works.
Key words: acoustic phonons, nanostructures, dynamic lattice model, thermal conductivity, electrical conductivity, coefficient „Figure of Merit” ZT, phonon engineering. The domain of study: physics of nanosystems.
The goal and objectives of the thesis: development of the concept of controlling thermal transport, kinetic and thermoelectric properties of nanoscale structures (planar heterostructures, quantum heterowires and 1D quantum-dot superlattices (1D QDSL)), affecting their phonon spectra. In order to achieve this goal the acoustic phonon spectra and group velocities in a threelayer planar heterostructures, as well as in rectangular quantum wires and heterowires with variable cross section, and 1D QDSL have been calculated and studied; the phonon thermal conductivity of planar structures, quantum wires and 1D QDSL were investigated; electron scattering rate, electron mobility and thermoelectric coefficient "Figure of Merit" in rectangular quantum wires and 1D QDSL have been calculated and studied.
Scientific novelty and originality the face-centered cubic cell (FCC) dynamic model of lattice vibrations was developed for planar structures: homogeneous layers and multilayered heterostructures, as well as for quantum wires of rectangular cross-section: homogeneous wires, wires in the shell (heterowires), wires of variable cross section and 1D QDSL was developed; the ways of decreasing and increasing of the lattice thermal conductivity in planar heterostructures, heterowires and 1D QDSL were established; the effect of the cladding material on the electron mobility and thermoelectric factor “Figure of Merit” ZT of nanostructures (quantum wires, covered with shells and 1D QDSL) was studied.
Theoretical importance: the concept of optimal control of the phonon thermal conductivity, mobility and thermoelectric properties of nanostructures is developed.
Significance of the work: practical implementation of this concept will improve thermal
management, i.e. transport, thermal and thermoelectric properties of nanoscale devices: fieldeffect
transistors and thermoelectric elements.