Nanocrystalline silicon powder was produced by using a vibratory disc mill in a top-down synthesis route from single crystalline silicon wafers and a polycrystalline bulk. The morphology and elemental composition of the produced silicon nanoparticles were investigated using microscopy (SEM and TEM) and energy dispersive x-ray spectroscopy (EDX) techniques. The particles consisted of a wide range of size distributions, ranging from a few faceted particles about m µ 3 1− in size to a large number

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... of much rounder particles in the nm 100 range. The EDX analysis reveals that the level of contaminants, which may have resulted from reactions with the milling medium, as well as with the atmospheric oxygen, remains insignificant for the duration of the milling process. The structural properties of the produced powder were investigated by means of X-ray diffraction (XRD), electron diffraction and Raman spectroscopy techniques. XRD reveals diffraction patterns with characteristic sharp peaks. It also shows a small broadening of the peaks widths, which may have arisen from a reduction in the powder's grain size and a possible buildup of lattice strain in the particles. Electron diffraction reveals patterns of continuous rings containing discrete reflections spots, which is indicative of a transformation from single crystalline to polycrystalline atomic structures in the case of powder milled from the wafer bulk. Raman spectroscopy study confirms that the milling process did not induce amorphous phases in the produced particle even after 5 hours of milling. This suggests that the milling of silicon from its bulk state with a laboratory disc mill is indeed a viable method of producing nanocrystalline silicon.