Nature of Paramagnetic Centers in Amorphous Boron

Abstract

ABSTRACTAmorphous powders of boron isotopes have been studied in the temperature range 100–450 K using EPR method. It was shown that paramagnetic centers with g=2.0029 ± 0.0001 are the holes captured on trapping levels. The centers represent volume defects. On the basis of temperature dependent measurements of the concentration of paramagnetic centers and their linewidth an energetical parameter of trapping level equal to 0.11eV over valence band was defined. An observed strong narrowing of the EPR line is connected with the increase of the frequency of delocalization of electrons with temperature. The structure of powders was studied by electron microscope method. Experimental results confirm the existence of icosahedral arrangement in amorphous boron.