The fundamentals of the chemical crystallization of diamond from the gas phase

The basic steps of researches for the synthesis of diamond from the gas phase is reviewed. The experimental results obtained on the thermal activation of a medium by using diamond powders as nucleation centers are considered. It has been established that the diamond rate from hydrocarbons exceeds that of graphite. Fractionation of the stable carbon isotopes is observed. The presence of hydrogen influences differently the growth of diamond and that of graphite.

The method of periodical pulse supersaturations is described, enabling one to obtain epitaxial films and isometrical diamond crystals. The method of activation of the gas medium by using an electric discharge allowed to obtain polycrystalline diamond films on the surface of metals and semiconductors. A possibility of the homogeneous formation of diamond in the gas phase has been established. The possibility of realization of this process in the cosmic space is discussed.