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Lecture

Localized electrical resistance of supported rGO measured using in-situ TEM

Thursday (29.09.2016)
12:15 - 12:30
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The electronic properties of reduced graphene oxide (rGO) can be altered through the reduction process parameters, meaning that it is a great candidate for many applications within energy storage. In order to fully utilize this promising material, it is essential to understand the behavior of the material on the nanoscale, including parameters such as substrate interactions and local wrinkling. Theoretical calculations of these topics are plenty, but experimental results to verify the conclusions are lacking. Here, we utilize in-situ transmission electron microscopy (TEM) to perform localized electrical measurements on wrinkled, supported rGO flakes. The rGO is deposited onto Au electrodes on a SiN membrane. The sample is loaded into an in-situ holder with an Au probe, which can be used to locally contact rGO to perform mechanical manipulation and electronic measurements. The results show that the overall resistance for this material is low, on the order of single kΩ, if the contact between the probe and the rGO is optimized. We find that the wrinkles reduce the contact resistance between the rGO and the probe. For more than 70 measurements, the trend shows that the overall resistance decreases with increasing amount of wrinkles underneath the probe. From these measurements, we estimate that the sheet resistance and maximal contact resistance for our measurements range from 5-20 kΩ/sq. and 6-20E-7Ω/cm2, respectively, which falls in line with other scanning probe measurements for graphene and metal contacts. These results provide evidence that wrinkled rGO on a substrate can transport electrons well and that it is thus not necessary to produce suspended, pristine graphene in order to benefit from its electrical transport properties.

 

Speaker:
Dr. Hanna Nilsson
Chalmers University of Technology
Additional Authors:
  • Dr. Ludvig de Knoop
    Chalmers University of Technology
  • Prof. Dr. John Cumings
    University of Maryland
  • Prof. Dr. Eva Olsson
    Chalmers University of Technology