Solution

ID: past-exam-of-the-mphil-in-micro-and-nanotechnology-enterprise-course-of-the-university-of-cambridge/2019/paper-1/section-a-i/1/iii/a/solution

A steady-current image is not supported by the electrical connection drawn. tunnelling atomic force microscopy requires a conducting AFM probe, an applied bias voltage and a continuous return path from the contacted region to the current amplifier. graphene is conducting, but a flake on insulating glass is not electrically grounded merely because the other side or edge of the glass is earthed. Charging transients or displacement current are not its steady conductivity. Add a metal contact actually touching the graphene before using its current contrast; ordinary force-based surface topography can still be recorded without that contact. The manufacturer's nanostructure measurements explicitly distinguish objects connected to conducting pads from unconnected particles on the same insulating substrate.[ref]

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