Diamond growth chemistry

The chemistry of diamond is a strong function of its growth form. The systematics of diamond growth and the factors influencing it have been reviewed by Gurney (1989), J. WUks and E. Wilks (1991), Harris (1992), Bulanova (1995), Mendelssohn and Milledge (1995), and Harlow (1998). 

As with methane, the photolysis of acetylene and subsequent chemistry involving the ethynyl (C2H) radical plays an important role in establishing the hydrocarbon balance in the atmospheres of the outer planets and their moons [4, 311]. The ethynyl radical is also an important reactive intermediate in combustion processes both it and acetylene have been implicated in soot formation, as well as in some models of diamond growth by chemical vapor deposition methods. 

Inorganic Chemistry of the Main-group Elements growth and martensitic conversion. It is conceded, however, that although it is inconceivable that the recognized diamonds for which mines are worked were produced by Galimov s process, the formation of microdiamonds by this process is possible. 

For example, although the story of carbon is as old as mankind itself, it is not fully told, and new chapters — sometimes new volumes -- are written from time to time. We appear to be in a period of a rapidly evolving carbon science right now. Not only is diamond film growth by chemical vapor deposition (CVD) an active area of research and development, but the discovery of fullerenes - the third allotrope of carbon - has opened up a whole new field of science with vast potential for both basic knowledge and applications. The paper that follows, authored by Professor Sir Harold W. Kroto, discusses the profound implications of the discovery of C q on the way we think about the structure of graphite and other layered materials. Because an important branch of chemistry — organic chemistry — deals with carbon and its compounds, carbon as a material quite naturally arouses the interests of chemists, particularly of materials chemists. 

This brief summary of the CVD process illustrates the importance of surface physics in the synthesis of diamond. Because the growth process itself is not directly accessible so far, most of the microscopic growth steps are inferred from experiments on diamond surfaces under idealized conditions and an analysis of the gas phase during CVD by mass as well as optical spectroscopies. These observations combined with estabhshed reaction sequences for the gas phase chemistry yield data such as growth rate and crystal habit and how they change with CVD conditions that can be measured and serve as benchmarks for particular growth models. 

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