Polycrystalline diamond films have been patterned on Si3N4 Si and SiO2 Si substrates by selective seeding with a double-layer mask via hot-filament chemical vapor deposition. High quality in the patterned diamond films and high selectivity were obtained by the process. The diamond films deposited on the insulators at different CH4 H2concentrations were studied by scanning electron microscopy and Raman spectroscopy. The process proved to be far less damaging to the substrates, and yet effective in developing patterns of diamond films on a large and different substrate. 2001 Elsevier Science B.V. All rights reserved.

One-dimensional (1D) nanowires, two-dimensional (2D) nanodendrites, and three-dimensional (3D) nanochains of SnO2 have been grown on single silicon substrates by Au-Ag alloying catalyst assisted carbothermal evaporation of SnO2 powders. One-dimensional twinning crystalline nanowires, 2D nanodendrites with spidery structure, and 3D nanochains with zigzag structure were reported. Three new peaks at 370, 470, and 555 nm in the measured photoluminescence spectra were observed, implying that more luminescence centers exist in SnO2 nanostructures due to nanocrystals and defects. The growth of the SnO2 nanostructure was discussed on the basis of the vapor-liquid-solid (VLS) mechanism.