Identification of Semiconductive Patches in Thermally Processed Monolayer Oxo‐Functionalized Graphene
Zhenping Wang, Qirong Yao, Christof Neumann, Felix Börrnert, Julian Renner, Ute Kaiser, Andrey Turchanin, Harold J. W. Zandvliet, Siegfried Eigler
Abstract
Abstract The thermal decomposition of graphene oxide (GO) is a complex process at the atomic level and not fully understood. Here, a subclass of GO, oxo‐functionalized graphene (oxo‐G), was used to study its thermal disproportionation. We present the impact of annealing on the electronic properties of a monolayer oxo‐G flake and correlated the chemical composition and topography corrugation by two‐probe transport measurements, XPS, TEM, FTIR and STM. Surprisingly, we found that oxo‐G, processed at 300 °C, displays C−C sp 3 ‐patches and possibly C−O−C bonds, next to graphene domains and holes. It is striking that those C−O−C/C−C sp 3 ‐separated sp 2 ‐patches a few nanometers in diameter possess semiconducting properties with a band gap of about 0.4 eV. We propose that sp 3 ‐patches confine conjugated sp 2 ‐C atoms, which leads to the local semiconductor properties. Accordingly, graphene with sp 3 ‐C in double layer areas is a potential class of semiconductors and a potential target for future chemical modifications.