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Indexed by:期刊论文

Date of Publication:2010-10-08

Journal:PHYSICAL REVIEW B

Included Journals:SCIE、Scopus

Volume:82

Issue:16

ISSN No.: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.