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 sp3‐patches and possibly C−O−C bonds, next to graphene domains and holes. It is striking that those C−O−C/C−C sp3‐separated sp2‐patches a few nanometers in diameter possess semiconducting properties with a band gap of about 0.4 eV. We propose that sp3‐patches confine conjugated sp2‐C atoms, which leads to the local semiconductor properties. Accordingly, graphene with sp3‐C in double layer areas is a potential class of semiconductors and a potential target for future chemical modifications.
Highlights
The mobility values of monolayer oxo-functionalized graphene (oxo-G) first increased with the release of adsorbed water, disproportionation up to 220 8C and decreased due to the formation of holes and surprisingly discovered stacked regions bearing sp3-C
By X-ray photoelectron spectroscopy (XPS), we identified a fraction of about 26 % CÀC sp3 and about 3.4 % CÀO/CÀOH/CÀOÀC, containing nanometer-sized sp3-patches as visualized by transmission electron microscopy (TEM)
The subsequent thermal treatments up to 300 8C do not induce an obvious change in chemical compositions (Figure 2 E–H), with the CÀC sp3 reaching about 26.1 % and CÀO/CÀOH/CÀ OÀC of 3.4 %
Summary
We present the structure evolution and related transport properties of oxo-G60% on the single-layer level by gradual thermally induced disproportionation. The mobility values of monolayer oxo-G first increased with the release of adsorbed water, disproportionation up to 220 8C and decreased due to the formation of holes and surprisingly discovered stacked regions bearing sp3-C.
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call