Synthesis of diamond from ethanol highly diluted in neon/hydrogen mixtures

In this work, we undertook a unique study of the growth kinetics of diamond in a hot-filament chemical vapor deposition (HF-CVD) reactor fed with the mixture C2H5OH + H-2 + Ne, varying the concentration of Ne from 0% vol. to 60% vol. Images obtained by scanning electron microscopy (SEM) show that th e addition of neon influenced the grain morphology, but diamond films with well-defined crystalline facets and good Raman quality were obtained up to a concentration of 60% vol. Ne. We verified that neon changes the diamond g rowth mechanism in the space between the grains, probably by the minimizati on of the hydrogenation kinetics in these regions. There is an apparent inc rease in the grain size and an increase in the flaws between the grains. Th e presence of Ne in the feed mixture also induces a broadening of the Raman peak characteristic of diamond, and this broadening may be related to an i ncrease in the density of vacancies within the diamond grains. (C) 2001 Els evier Science B.V. All rights reserved.