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 z eolite 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 photoemissio n spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). Nons toichiometric silicon nitride and unterminated silicon nanoparticles with s ize of estimated to be similar to 5.4 Angstrom in diameter were existed. Th ey 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 anneal ing was studied at 373 K. Thr change of silicon surface state (unterminated silicon nanoparticles) to hydride species was observed concurrently with b reaking of the NHx species. This result implies that the NHx species remain ed on the silicon particles form Si3N4 like bonds and the dissociated H-spe cies are bound to the unterminated silicon surface. (C) 1999 Elsevier Scien ce B.V. All rights reserved.