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The field emission properties of “porous diamond-like” carbon structures have been characterized. A hot filament chemical vapor deposition system fed with ethyl alcohol vapor diluted in helium was used to deposit the samples. Morphological analysis by field emission scanning electron microscopy revealed that they had a highly porous structure, which was attributed to the modification of the kinetics of the carbon deposition process due to the presence of helium as a buffer gas. Micro-Raman spectroscopy showed two peaks in the graphene and microcrystalline graphite frequencies and a new peak at 1620 cm−1. Low threshold fields (Et) and hysteresis in the current versus voltage characteristic have been observed, and a model to explain the hysteresis is proposed.

We show that the electrical properties of nitrogen-doped nominally undoped polycrystalline chemical vapor deposited diamond films are modified by post-deposition heating in an oxidizing atmosphere. We found that the first heating cycle in air in the temperature range of 300–673 K decreased the graphitization content still present in the diamond surface and that after the second heating cycle the electrical resistance versus temperature curves became stabilized. Using a flow of argon with residues of oxygen over the surface of the sample during the heating cycles, the stabilization of the resistance-temperature dependence also occurred but only after the fourth heating cycle. The results suggest the existence of an oxidation mechanism of the nondiamond carbon atoms present at the diamond surface. After stabilization, the deep donor ionization energy was found to be Ed=1.62±0.02 eV. All results brought together strongly suggest that this level is due to single nitrogen atoms that occupy substitutional latti...

Diamond polycrystals deposited by the hot‐filament chemical vapor deposition method on silicon (100) substrates have been examined by atomic force microscopy (AFM) in air. Measurements of the diamond unit cell show periodic spacings between 0.34 to 0.37 nm in a very good agreement with the theoretical value of the bulk constant of natural diamond (0.356 nm). Hybridized sp3 bonds can also be observed at the (111) surface.

Polycrystalline Si films with average grain sizes of ∼8 μm have been grown by laser‐induced chemical vapor deposition from SiCl4. A cw CO2 laser operated at 10.6 μm was used to provide local heating of quartz substrates in an otherwise cool reactor to initiate the endothermic decomposition reaction. Deposition rates of 5.1 μm/min were obtained for films grown at an incident laser power of 18.9 W, resulting in sharply defined mesa structures due to the occurrence of the reverse reaction, etching of free Si, at cooler regions of the substrate surface closer to the edge of the 6‐mm irradiated zone. The diameter of the mesas was 1.4 mm with thicknesses up to 26 μm. Three modes of film growth, depending on the incident laser power, were observed.