Growth of spherical boron oxynitride nanoparticles with smooth and petalled surfaces during a chemical vapour deposition process

A rich variety of hollow and solid (without internal hollow spaces) spherical boron oxynitride nanoparticles (BNO-NPs) with smooth or petalled surfaces were synthesized during a boron oxide-assisted chemical vapour deposition (BOCVD) process. Diverse BNO-NPs were obtained while utilizing different precursors, gas flow rates and synthesis temperatures in the range of 1200-1430 degrees C. The BNO-NP morphologies, atomic structures and spatially-resolved chemical compositions were studied by scanning (SEM) and transmission electron microscopy (TEM), X-ray diffraction (XRD), energy-dispersive X-ray, Fourier-transform infrared and confocal Raman spectroscopy. Particle size distributions were measured using dynamic light scattering under visual microscopic control. A growth model of different spherical BNO-NP types based on the detailed analysis of physical-chemical processes at different BOCVD stages was proposed. A new type of spherical BNO-NPs of hedgehog morphologies with BN nanowires on their surfaces was first predicted in accordance with the designed model and then experimentally verified.