Article Abstract:
The irradiation of spherical carbon particles with concentric graphite-like shells (carbon onions) by electrons produces diamonds in their cores. The carbon onions, on heating to almost 700 degrees celsius and irradiation, form a compressed structure. The compression is due a decrease in the distance between the lattice planes from the outer to inner layer. The irradiation of these structures produces cubic diamonds that grow with further irradiation. The carbon onions cores may be polycrystalline or monocrystalline. The diamonds are stable at room temperature while the carbon shells are unstable.
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Article Abstract:
A non-equilibrium low-pressure process has been used to synthesize high-purity diamond microparticles. This process is based on a short and intense heat pulse which produces nucleation and growth of diamond in the dense carbon vapour. The carbon plasma is created in a stainless-steel vacuum-tight chamber by an electric pulse discharge between two sharpened tips of high purity graphitic electrodes. It is anticipated that adjustment of experimental parameters to maximize the density of the carbon-vapour phase will make it possible to grow larger diamond crystals.
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Article Abstract:
Research investigating the electrical conductivity of diamond insulators is presented. Particular attention is given to applications of the technique of atomic scanning tunnelling microscopy and of resonant electron injection to obtain imaging of insulating diamond at atomic scale.
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