Silicon Rich Oxide (SRO) has been considered as a material to overcome the drawbacks of silicon to achieve optical functions. Various techniques can be used to produce it, including Low-Pressure Chemical Vapor Deposition (LPCVD). In this paper, a brief description of the studies carried out and discussions of the results obtained on electro-, cathode-, and photoluminescence properties of SRO prepared by LPCVD and annealed at 1,100°Care presented. The experimental results lead us to accept that SRO emission properties are due to oxidation state nanoagglomerates rather than to nanocrystals. The emission mechanism is similar to Donor-Acceptor decay in semiconductors, and a wide emission spectrum, from 450 to 850 nm, has been observed. The results show that emission is a function of both silicon excess in the film and excitation energy. As a result different color emissions can be obtained by selecting the suitable excitation energy.

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This paper describes the results from systematic experiments performed to investigate the influence of different substrate-filaments distances, surface-substrate temperatures and reaction of precursors during the growth of Ultrananocrystalline Diamond (UNCD) films via the hot filament chemical vapor deposition (HFCVD) process. The experimental results provide valuable information to understand the important role of key molecules (CHx, x=1, 2, 3) and atoms (H), resulting from the cracking of precursor molecules (CH4, H2) on the hot surface of the filaments, and the contribution of argon (Ar) inert gas atoms, all interacting on the surface of the substrates when using different filaments-substrate distances to produce films with different structures and properties. The interaction of the cracked molecular and atomic species at different filamentssubstrate distances, play a critical role in the nucleation and growth of films with different structures, as observed by complementary analytical techniques. Films grown at 5, 15, and 30 mm filaments-substrate distances exhibit graphite-disordered graphene phases, while those grown at 20 mm distances exhibit mixed large UNCD-minor graphite mixed phases, and those grown at 25 and 35 mm distances exhibit pure UNCD phase. UNCD films grown at ~ 600 ˚C exhibit grain boundaries with sp 2 and Trans-Polyacetylene (TP-A) dangling chemical bonds and low sheet resistance (~5 ), while UNCD films grown at relativity low temperature (~490 °C) exhibit high sheet resistance (~8 M) and more TP-A dangling bonds. The results presented in this paper indicate that UNCD and mixed UNCD/disordered graphene/graphite films can be grown with tailored resistivity enabling potential applications in electronic power devices.

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