Interactions of deuterium and hydrocarbon species with the diamond C(111) surface

Abstract

AES, XPS, TDS and LEED have been used to study the adsorption, the desorption and the reaction behavior of D atoms and CHx (1 ≤ x ≤ 3) species on the diamond C(111) surface. It is found that a small amount of chemisorbed D atoms can induce the (2 × 1) to (1 × 1) phase transition and hold the sp3 structure up to nearly 1400 K. The structural transformation can also be monitored by the optical second-harmonic generation technique. Thermal desorption of deuterium occurs mainly around 1300 K. Adsorption of CHx can also induce the phase change but not as readily as the D atoms. Annealing of the adlayer at a high temperature results in the partial conversion to graphitic carbon. D atoms can react with both the adsorbed CHx and the surface graphite. The surface bonding characteristics and the relevance of present results to the diamond CVD process are briefly discussed. © 1991.