title: An integrated capacitance bridge for high-resolution, wide temperature range quantum capacitance measurements.
abstract: We have developed a highly sensitive integrated capacitance bridge for quantum capacitance measurements. Our bridge, based on a GaAs HEMT amplifier, delivers attofarad (aF) resolution using a small AC excitation at or below k(B)T over a broad temperature range (4-300 K). We have achieved a resolution at room temperature of 60 aF/√Hz for a 10  mV ac excitation at 17.5 kHz, with an improved resolution at cryogenic temperatures, for the same excitation amplitude. We demonstrate the utility of our bridge for measuring the quantum capacitance of nanostructures by measuring the capacitance of top-gated graphene devices and cleanly resolving the density of states.
authors.affiliation: Department of Electric Engineering, Stanford University, 476 Lomita Mall, Stanford, California 94305, USA [corrected].
authors.forename: Arash
authors.initials: A
authors.lastname: Hazeghi
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Sulpizio
authors.forename: Georgi
authors.initials: G
authors.lastname: Diankov
authors.forename: David
authors.initials: D
authors.lastname: Goldhaber-Gordon
authors.forename: H S Philip
authors.initials: HS
authors.lastname: Wong