11{sup left}B and 10{sup left}B MAS NMR studies of distorted tetrahedral coordination of wurtzite boron nitride

摘要

Magic-angle spinning nuclear magnetic resonance of 11{sup left}B and 10{sup left}B (11{sup left}B and 10{sup left}B MAS NMR) spectroscopy has been conducted to characterize distorted chemical bonds of wurtzite boron nitride (wBN), in which boron atoms are coordinated by four nitrogen atoms. Although X-ray analysis gives the difference from ideal tetrahedral symmetry by simulation, comparison of results of MAS NMR measurements gives proof of anisotropic symmetry Anisotropy was typically revealed in the broadened linewidth of the 10{sup left}B MAS NMR spectrum. In contrast, defective density and impurities in wBN must not be very high, since a small broadening of the linewidth in 11{sup left}B MAS NMR spectrum was revealed. These situations contrast with results of 11{sup left}B and 10{sup left}B MAS NMR measurements of cubic boron nitride (cBN) films prepared by plasma chemical vapor deposition.