Abstract
We investigate the low-temperature electron transport properties of chemically reduced graphene oxide (RGO) sheets with different carbon fractions of 55 to 80. We show that in the low-bias (Ohmic) regime, the temperature () dependent resistance () of all the devices follow Efros-Shklovskii variable range hopping (ES-VRH) with decreasing from 3.1×10 to 0.42×10 K and electron localization length increasing from 0.46 to 3.21 nm with increasing fraction. From our data, we predict that for the temperature range used in our study, Mott-VRH may not be observed even at 100 fraction samples due to residual topological defects and structural disorders. From the localization length, we calculate a band-gap variation of our RGO from 1.43 to 0.21 eV with increasing fraction from 55 to 80, which agrees remarkably well with theoretical predictions. We also show that, in the high bias non-Ohmic regime at low temperature, the hopping is field driven and the data follow providing further evidence of ES-VRH.
- Received 4 September 2012
DOI:https://doi.org/10.1103/PhysRevB.86.235423
©2012 American Physical Society