Characterization of nitrogen terminated silicon nanoparticles on AFI zeolite with X-ray and ultraviolet photoelectron spectroscopies

Nitrogen terminated silicon nanoparticles were synthesized on AFI AlPO4-5 zeolite by pulsed Laser ablation of silicon target in the presence of 1.33 x 10(-5) Pa of ammonia, and were characterized in situ by X-ray photoemission spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). Nonstoichiometric silicon nitride and unterminated silicon nanoparticles with size of estimated to be similar to 5.4 Angstrom in diameter were existed. They were found to migrate and diffuse into the AlPO4-5 channels at 373 K and migrate back to the external surface at 503 K. The effect of sample annealing was studied at 373 K. Thr change of silicon surface state (unterminated silicon nanoparticles) to hydride species was observed concurrently with breaking of the NHx species. This result implies that the NHx species remained on the silicon particles form Si3N4 like bonds and the dissociated H-species are bound to the unterminated silicon surface. (C) 1999 Elsevier Science B.V. All rights reserved.