Tuning Graphene Oxide Band Gaps with Electricity

Spatio-temporal Analysis of Electric Field Induced Solid State Reduction Dynamics of Graphene Oxide Thin Films for Controlled Bandgap Modulation

N. Prasad, S. Tanwar, S. Mukhopadhyay and T. Kundu

J. Phys. Chem. C 124, 21874-21885 (2020)

An electric field-induced reduction mechanism studied for tuning the band gap of graphene oxide thin films in a two-electrode configuration on a SiO2/Si substrate is presented. During the reduction, temporal changes in the sheet resistance and optical band gap of the film were monitored and the correlation between these parameters in this solid state chemical reaction was established. As the reduction progresses, three different kinds of temporal dependence of electrical characteristics were observed. Further, from spatio-temporal analysis of the reduction of graphene oxide in such a disordered system, an analytical model was developed to describe the time dynamics of the reduction process. This model provides the flexibility for in situ monitoring the band gap of the material in terms of sheet resistance during the reduction, hence allowing device optimization for different applications. It is envisaged that this reduced graphene oxide-based tunable platform may find enormous potential for various electronic and optoelectronic applications.