Figure 4
From: Observation of negative differential resistance in mesoscopic graphene oxide devices
NDR mechanism in reduced graphene oxide device. (a) Schematic illustration of the device under measurement, where the upper image shows measurement under vacuum and the lower one in the ambient environment and the blue arrows in both schematics indicate current direction. Electric charge in the channel lowers the activation energy of electrochemical reactions, involving thin adsorbed water layer, which results in the chemisorption of the dissociated OH− ions on the GO surface, as shown by curved red arrows. (b) I-V characteristics showing measurement in the ambient and vacuum environment. (c) Low power Raman spectra of GO and Joule heated GO, where the measurement was carried out twice to record the reduction in consecutive sweeps at the same spot. The inset shows a microscopic image of the sample after two electrical sweeps. (d) I-V characteristics of the GO device annealed from 100 oC to 400 oC with the inset figure showing the same data in semi-log scale.
