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Information × Registration Number 0219U100096, 0115U001630 , R & D reports Title The development of radiospectroscopic diagnosis methods of functional nanostructured materials for opto- nanoelectronics and medicine. popup.stage_title Head Кончиць Андрій Андрійович, Registration Date 17-01-2019 Organization V. Lashkaryov Institute of semiconductor physics popup.description2  Biomorphic carbon matrices (BСM) were obtained by pyrolysis of wood of different types, after which the finished BСMs were converted into SiC ceramics by their impregnation with liquid silicon and subsequent heat treatment. The properties of BСM and biomorphic SiC samples were investigated using scanning electron microscopy (SEM), Raman scattering (RS) and electronic paramagnetic resonance (EPR) techniques. It has been established that all BCM samples contain large (10-50 μm) and small (1-5 μm) pores with a surface density of ≈10^9 m^-2 and 10^11 m^-2, respectively. From the analysis of the Raman spectra, the size of the carbon clusters is estimated to be 5-11 nm, depending on the type of sample. The electronic properties of BCM and SiC ceramics have been investigated by EPR method. The theoretical analysis of the EPR spectra showed that spin resonance in BCM is due to the contribution of three subsystems: free electron spins, "quasifree" electronic spins from the tail of density states below the conduction band, and localized spins whose nature is associated with dangling carbon bonds . The contribution of different subsystems depends on the ratio of different structural phases, such as sp2-hybridized graphite-like carbon structure, amorphous phase, etc. The EPR line of the BCM is tens of times narrowed by the pumping of porous specimens and eliminating the influence of paramagnetic oxygen O2. The transformation of BCM into SiC ceramics by impregnating BCM samples with liquid silicon is clearly traceable in the Raman spectra and EPR. The optimum technological parameters for obtaining high-quality SiC ceramics are found. It has been established that the electronic properties of this ceramics are due to the presence of residual graphite-like carbon nanoclusters. Product Description popup.authors popup.nrat_date 2020-04-02 Close