Synergetic interplay between pressure and surface chemistry for the conversion of sp 2 -bonded carbon layers into sp 3 -bonded carbon films
- Citation data:
Carbon, ISSN: 0008-6223, Vol: 106, Page: 158-163
- Publication Year:
- Repository URL:
- Chemistry; Materials Science; TOTAL-ENERGY CALCULATIONS; DIAMOND PHASE-TRANSITION; WAVE BASIS-SET; REVERSIBLE HYDROGENATION; HEXAGONAL DIAMOND; GRAPHITE; GRAPHENE; MECHANISM; TRANSFORMATION; NUCLEATION
The effects of the interplay between pressure and surface chemistry on the transformation of few-layer graphene into an sp 3 -bonded carbon film were investigated with first-principles density functional theory calculations including ab initio molecular dynamics. N 2 H 4, H 2 O, and He were each considered as a candidate pressure medium. Compared with the bulk graphite, the surface chemistry overwhelmingly governed the conversion energetics for nanometer-thick graphene layers. A hydrogen-donating medium reduced the required conversion pressure compared with an inert one; the conversion pressure obtained by using N 2 H 4 was 40% of the corresponding pressure obtained with He. We suggest that pressurizing the cell through hydrogen-donating pressure media has the advantage from the surface chemistry by concentrating hydrogen atoms on carbon surfaces.