Release Time:2019-03-09  Hits:

Indexed by: Journal Article

Date of Publication: 2010-10-08

Journal: PHYSICAL REVIEW B

Included Journals: Scopus、SCIE

Volume: 82

Issue: 16

ISSN: 1098-0121

Abstract: We determine the energy diagram of graphene oxides (GOs) as a function of oxygen and hydrogen chemical potentials by systematic first-principles calculations. The diagram reveals that thermodynamically stable GOs can exist only in stringent growth conditions in the form of hydroxyl, epoxy, or mixed hydroxyl/epoxy phases. There is no mixed phase with sp(2) carbon because of substrate relaxation, which is unique to two-dimensional system with little coupling in the third direction such as graphene. The mixed phase observed experimentally is interpreted instead, in terms of a kinetic stability of nonequilibrium grown GOs against phase separation.