Preparation of boron nitride nanocapsules by plasma-assisted pulsed laser deposition

Nanocapsules of crystalline boron nitride (BN), whose diameters ranged from 50 to 300 nm, have been synthesized by pulsed-laser-vaporization of BN, where the laser plume was controlled by the modulated plasma jet flow field. Their shapes varied from polyhedrons to cocoons and the interlayer spacings along the c axis were enlarged according to their size and shape (curvature). Without the synchronization of the laser pulses with the plasma modulation, soot-like BN was obtained. This soot-like BN represented the trace of the precursor state which should have been molded into the nanocapsules if it had been just hit by the modulated plasma jet at the appropriate speed. (C) 2002 American Institute of Physics.