Savchenko D. Electronic and magnetic properties of paramagnetic centers in carbon-containing materials

In this theses the properties of paramagnetic centers in carbon-containing materials by continuous wave and pulse radiospectroscopy were established. In 6H, 4H, 15 R polytypes of silicon carbide (SiC) of n-type the ligand structure of nitrogen (N) donors was determined. It was proposed that the N donors residing «k2» position in 6H SiC lattice and having deep levels in the bandgap should substitute Si atoms. At the same time the carbon excess in 15R SiC leads to the appearance of deep N donor levels in three cubic positions residing Si atoms. The spin relaxation mechanisms and times for N donors in 6H SiC monocrystals were determined. It has been found that the presence of the hopping conduction, donor clusters and conduction electrons (CE) has an impact on phase memory time of quantum state for N donors. Magnetic and electrical properties of CE in highly and low-doped 6H, 4H and 3С SiC monocrystals were revealed and studied. Magnetic properties of C-related centers in a-Si1−xCx:H, a-SiCxNy, DLC:Cr, Si:C and SiO2:C films were investigated. In SiO2:C nanocomposites the quantum-size effect for CE localized in C nanodots was found. The size-dependent effect for N donors in SiC nanoparticles was found. The triplet center from N-vacancy pair in self-assembled 6H SiC nanostructures was revealed and its parameters were determined.