Bratus' V. Nature and structure of paramagnetic defects in GaAs, SiC and silicon-based materials with nanostructures

The thesis deals with a solution of a problem to understand nature and structure of extrinsic and intrinsic paramagnetic defects in GaAs, SiC and silicon-based materials with nanostructures. It has been clarified that resonant spin absorption of neutral Mn acceptor has electric-dipole nature. Symmetry and hyperfine parameters have been defined for shallow boron center in 3C-SiC. A model of BSi has been examined, it explains the EPR spectrum parameters and temperature behavior. The spin-Hamiltonian parameters of three dominant defects Ky1, Ky2 and Ky3 have been determined in electron-irradiated p-type 6H-SiC crystals. A comparison of hyperfine parameters obtained from experiment and first-principal calculations allows to identify the defects as a positively charged carbon vacancy in three inequivalent positions of 6H-SiC lattice. The T5 and EI3 centers have been identified as positive and neutral charge state of the carbon <100> split interstitial in SiC respectively. A model for the Pb defect at Si/SiO2 interface has been proved. Paramagnetic defects have been revealed and identified in a lot of silicon materials formed with various evaporation techniques and ion implantation into Si/SiO2 structures.