Nucleation on an Intermediate Layer of Diamond-like Amorphous Carbon

2 Nucleation on an Intermediate Layer of Diamond-like Amorphous Carbon 

The HRTEM study of diamond nucleation and growth on copper TEM grids in HFCVD by Singh provides direct evidence for the formation of a diamond-like amorphous carbon layer. The intermediate layer is 8-14 nm thick, in which small diamond microcrystallites approximately 2-5 nm across were embedded (Fig. 6a), and large diamond crystallites were observed to grow from these microcrystallites (Figs. 6b-c). 

It was suggestedt that the diamond microcrystallites are formed as a result of direct transformation of the a-C into diamond, with the intermediate layer providing nucleation sites on which the large diamond crystallites grow. Based on these experimental observations, a detailed mechanism of diamond nucleation and growth on copper in HFCVD was proposed, as depicted in Fig. 7. 

Overall, these experimental results confirm that diamond crystallites are not located directly on the substrate surface but on an intermediate amorphous layer. Nucleation of diamond occurs readily on the 

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