CAPACITIVE CONTACTS: MAKING FOUR-POINT CHARACTERIZATIONS WITHOUT OHMIC CONTACTS

Four-point measurements are carried out on a Hall bar using specially designed capacitive contacts, reproducing the transport characteristics Rxx measured using standard ohmic contacts. All Rxx measurements using various combinations of ohmic and capacitive contacts are in quantitative agreement, with a calibrated scaling factor arising because of the device and measurement setup capacitances. Also amplitude and phase measurements represented with the Bode plots for all combinations of ohmic and capacitive contacts are carried out and the results compare favorably with our circuit analysis.