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A systematic study is reported on the effects of nano-diamond seeding density on the growth, quality, and morphology of diamond films. A process is described to examine nano-diamond seeding densities 4 × 108, 8 × 1010, and 2 × 1012 cm−2 on silicon wafers. The diamond film is grown using hot-filament chemical vapor deposition with CH4/H2/O2 feed gases and varying growth time to determine properties at coalescence and as thickness increases. Polycrystalline morphology is examined by scanning electron and atomic force microscopy. Both vertical and lateral growth rates are found to be higher for sparse seeding prior to coalescence. Following coalescence, the growth rate is similar for all densities. The development of polycrystals is found to be influenced by the initial growth with smaller mean lateral size at higher seeding density and reduced surface roughness that also improves with thickness to reach ≲90 nm at a thickness of 6.4 μm. The crystal quality is examined by micro-Raman spectroscopy from the sample surfaces and line images from cross sections. Narrowing of the diamond phonon peak shows material quality to improve with the thickness, at a given seed density, and as density increases. Concomitant improvements are seen from the relative intensity of the diamond phonon and Raman bands from non-diamond carbon. Cross-section micro-Raman results suggest improved diamond film quality and crystallinity near the substrate interface as well as at the growth surface for the film grown with 2 × 1012 cm−2 seed density compared to 4 × 108 and 8 × 1010 cm−2. X-ray photoelectron spectroscopy confirms these trends at the diamond surface.

We report a simple and feasible technique for the formation of well-distributed nickel nanodot arrays on both oxidized and unoxidized silicon substrate by a conventional annealing process. The shape and distribution of nickel nanodots were maintained by adjusting annealing temperature, time and the SiO2 buffer layer thickness in between nickel film and the silicon substrate. The diffusion of nickel into the silicon is significantly reduced when the nickel film on the oxidized silicon substrate is annealed at high temperature. From this conventional annealing technique, we achieve a maximum nickel nanodots density up to (7.94±1.92) nanodot counts/µm2 on the oxidized silicon substrate with a well-defined spherical shape by adjusting the thickness of nickel film as well as buffer SiO2 layer. In the next experiment, the surface charge distribution on the nickel nanodot arrays were characterized through the Kelvin probe force microscope (KPFM) on tapping mode. It is found that the nickel nanodots can store and release the electric charges under an applied bias voltage.