CONCENTRIC SHELLED AND PLATE-LIKE GRAPHITIC BORON-NITRIDE NANOPARTICLES PRODUCED BY CO2-LASER PYROLYSIS

The morphology of graphitic boron nitride nanometric particles produce d from the reaction between ammonia and borontrichloride heated by a C O2 laser is investigated by high resolution electron microscopy. A var iety of roughly spherical particles are revealed, consisting of concen tric graphitic shells and ranging in size from 20 to more than 100 nm and in shape from hollow to filled-to-the-center. This onion-like conf iguration is very similar to that observed in carbon materials. Anothe r morphology made of stackings of a few perfectly flat graphitic sheet s (10 to 50 layers, 50 nm in length) is developed after heat treatment .