Damaging Graphene with Ozone Treatment: A Chemically Tunable Metal−Insulator Transition

Abstract

We present a multiscale ab initio study of electronic and transport properties of two-dimensional graphene after epoxide functionalization via ozone treatment. The orbital rehybridization induced by the epoxide groups triggers a strong intervalley scattering and changes dramatically the conduction properties of graphene. By varying the coverage density of epoxide defects from 0.1 to 4%, charge conduction can be tuned from a diffusive to a strongly localized regime, with localization lengths down to a few nanometers long. Experimental results supporting the interpretation as a metal-insulator transition are also provided.

Magnetotransport in disordered graphene exposed to ozone: From weak to strong localization

“…[17][18][19] By contrast, recent calculations show that this is not the case for graphene exposed to ozone. 37 In addition, even if such a gap was created, our measurements suggest that it would be very small. Indeed, we obtain an energy gap of 1 meV when we compare the temperature dependence of the resistivity at the Dirac point to a thermal activation behavior.…”

Insulating behavior of an amorphous graphene membrane

“…However, despite the large amount of disorder, such graphene flakes (when deposited onto oxide substrates) usually maintain a finite conductivity down to very low temperatures owing to electron-hole puddles-induced percolation effects that preclude localization phenomena close to the Dirac point 6 . The predicted Anderson localization in two-dimensional disordered graphene has been hard to measure in non intentionally damaged graphene, in contrast to chemically modified graphene 7,8 . Nevertheless, in a recent experiment it was possible to screen out electron-holes puddles using sandwiched graphene in between two boron-nitride layers, together with an additional graphene control layer 9 .…”

“…Such method, pioneered in 28 , has been successfully applied to many different types of systems, and in particular it has allowed to scrutinize Anderson localization in oxygen functionalized graphene 8 . The zero-frequency conductivity for carriers at energy E is computed as…”

Charge and Spin Transport in Disordered Graphene-Based Materials

“…However, despite the large amount of disorder, such graphene flakes usually maintain a finite conductivity down to very low temperatures (when deposited onto oxide substrates) owing to electron-hole puddles (charge inohomogeneities fluctuations)-induced percolation effects which limit localization phenomena [2]. The predicted Anderson localization in two-dimensional disordered graphene has been hard to measure in non intentionally damaged graphene, in contrast to chemically modified graphene [230,231]. In a recent experiment, it was however possible to screen out electronholes puddles using sandwiched graphene in between two boron-nitride layers, together with an additional graphene control layer [113].…”