Observation of anomalous transport characteristics in graphene-oxide thinfilm

This paper describes experimental results of an anomalous electrical transport properties of graphene-oxide (GO) thinfilm. A nonlinear current-voltage (I-V) characteristic has been observed and analyzed with various current-transport mechanisms such as thermionic emission, space-charge limited conduction (SCLC), and Poole-Frenkel (P-F) conduction. Observation of high ideality factor reveals that the current transport is not influenced by thermionic emission. Interestingly, a characteristic transition of current from Ohmic to SCLC has been noticed. P-F conduction has been evidenced through the straight line fit observed between ln(I/V) and V1/2. The recombination tunneling with SCLC is found to be the main conduction process compared to thermionic emission and P-F conduction. The charge traps present in the GO bulk causes SCLC and P-F conduction. A plausible mechanism for each current transport phenomenon is discussed in detail. The presence of charge traps in GO is further evidenced through Raman mapping analysis. Our study further advances the understanding of the fundamental charge transport mechanisms appeared in GO thinfilms which will be an essential parameter in the development resistive memory switching applications.