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Optic and photoelectric phenomena in anisotropic materials


Author: Dorogan Andrei
Degree:doctor of physics and mathematics
Speciality: 01.04.10 - Semiconductors physics and engineering
Year:2019
Scientific adviser: Nicolae Sîrbu
doctor habilitat, professor, Technical University of Moldova
Institution: Technical University of Moldova

Status

The thesis was presented on the 26 April, 2019 at the meeting of the Scientific Council and now it is under consideration of the National Council.

Abstract

Adobe PDF document0.86 Mb / in romanian

Thesis

CZU 535.2/.3 (043.2)

Adobe PDF document 6.62 Mb / in romanian
186 pages


Keywords

anisotropy, birefringence, gyration, dichroism, heterostructures, quantum wells, optic filters, photoreceivers

Summary

Thesis structure. The Ph.D. thesis comprises the introduction, four chapter, conclusions bibliography (151 titles), 7 appendixes, 139 pages of main text, 78 figures and 2 tables. The obtained results are published in 50 scientific articles.

Domain of study consists in the study of anisotropy and spectroscopy of excitonic polaritons of birefringent ZnAs2 crystals, In0,3Ga0,7As/GaAs nanostructures and estimation of basic optic properties and constants.

The scopes of the papers consists in the experimental study of anisotropy of semiconductor crystals with reduced symmetry, establishing the mechanisms of anisotropy of optical properties, study of phenomena at the crystals’ surface and at the interfaces of metal and other semiconductors, elucidating the practical applications of optical and photoelectric dichroism, study of parameters and properties of In0,3Ga0,7As/GaAs quantum well structures with the aim of developing optoelectronic devices.

The scientific novelty and originality consists in the characterization of optical properties of birefringent materials and structures with quantum wells and the determination of fundamental optical parameters at high resolution. The originality of the proposed solutions is to determine the possibility of developing optoelectronic devices sensitive to the polarization of optical radiation used in optical communication systems and other domains.

The solved scientific problem lies in the determination and calculation of the fundamental optical parameters of excitonic polaritons in ZnAs2 birefringent crystals with C2h5 symmetry and of the electronic transitions in the fundamental absorption band of anisotropic materials and heterostructures with quantum wells for optoelectronic devices development purposes.

The theoretical significance of the paper is the calculation of spectra of ZnAs2 excitonic polaritons based on the dispersion relations, the determination of the effective masses of electrons and holes, determination of fundamental optical parameters using Kramers-Kronig relations for ZnAs2 crystals and heterostructures with quantum wells.

The applicative value of the paper is the demonstration of the possibility of developing electronic devices sensitive to linear polarized radiation based on ZnAs2 anisotropic crystals and the objective estimation of the quality and parameters of heterostructures with quantum wells using optical spectroscopy methods.