The Electrical Characterization of Nanomaterials

In this study, graphene oxide and reduced graphene oxide (rGO) were electrically characterized to evaluate how reduction and the different reduction techniques affect electrical conductivity. A four point probe procedure was developed using a Cascade Microtech Manual Probe Station and a Keithley 2636B Sourcemeter to measure the current voltage (I-V) behavior of the samples. Voltage sweeps from 0 to 1 V were applied to the samples and the resulting current responses were measured to generate I-V curves. The unreduced GO samples were tested on silicon wafer substrates, exhibiting very small currents, averaging approximately 77 pA at 1 V, indicating high electrical resistance. The GO samples were then reduced using four methods: solar, chemical, laser and thermal reduction. The solar reduced sample produced nearly identical current values as the unreduced GO, indicating minimal change in electrical behavior and minimal reduction. Laser reduction increased the maximum current to approximately 3.6 μA, while chemical reduction produced a larger current response of 19.4 μA. The thermally reduced sample resulted in the largest increase in electrical response, reaching approximately 274 μA under the same voltage sweep. These results indicate that the method of reduction significantly influences the electrical behavior of the GO, with thermal reduction resulting in the greatest increase in current, and therefore conductivity. Understanding how reduction methods affect electrical properties is important for the development of emerging GO based applications.