Formation of GeO 2 under Graphene on Ge(001)/Si(001) Substrates by Water Vapor

Abstract

Water vapor penetrates through defects in graphene layers grown on Ge(001)/Si(001) substrates and oxidization of germanium forming GeO2 is described. The presence of trigonal GeO2 underneath of graphene has been identified by Raman measurements. It has been found that formation of blisters of GeO2 under graphene leads to dramatic increase of intensity of graphene Raman spectrum. The increase is the most likely due to screening of graphene by GeO2 from nano-faced Ge(001) surface.