CHEMISORPTION OF FLUORINE, HYDROGEN AND HYDROCARBON SPECIES ON THE DIAMOND C(111) SURFACE

AES, XPS, TDS and LEED have been used to study the interactions of F, H and CHx species with the diamond C(111)-(2 x 1) surface. It is found that a small quantity of chemisorbed H atoms can induce the (2 x 1) to (1 x 1) phase transformation and uphold the sp3 structure to nearly 1400 K. In contrast, F atoms and CHx species are unable to do so. The distinct bonding characteristics of these adsorbates manifest clearly the diverse effects on the surface electronic and geometrical structures. It is further shown that H can react with and replace the preadsorbed CHx, while subsequent exposure to CHx can do the same to the preadsorbed H atoms. The results are relevant to a better understanding of the basic mechanisms involved in the diamond CVD process.