Local order determination in SiCN(AlY) laser-synthesized nanopowders by x-ray photoemission spectroscopy

Chemical bonding in SiCNAlY(O) nanometric powders was investigated by x-ray photoemission spectroscopy. The powders were prepared by laser pyrolysis of binary mixtures of liquid hexamethyldisilazane and disolved solid isopropoxydes. As-prepared powders are amorphous and the atomic proportion of aluminum and yttrium do not exceed 1 at. %. They were annealed at 1600 °C under N2 atmosphere and we followed the evolution of the bonding configuration with annealing treatment for the composition with a C/N atomic ratio equal to 0.78. Two other compositions were studied (powders annealed at 1600 °C): a carbon rich powder (C/N=5.05) and a nitrogen rich powder (C/N=0.09). The strong increase of Al 2p and Y 3d peak intensities relatively to Si 2p peak intensity with annealing underlines an increase of the Al and Y content in superficial layers after annealing. The analysis of the chemical shift of Al 2p core level after annealing underline the appearance of Al–N bonds at 1600 °C. The chemical environment of Y atoms ...