Ultra-compact, passive, varactor-based wireless sensor using quantum capacitance effect in graphene
First Claim
1. A sensor comprising:
- a graphene quantum capacitance varactor having a graphene layer, wherein capacitance of the graphene layer changes in response to electrical charge collected proximate to the graphene layer; and
a readout circuit responsive to the capacitance of the graphene layer and configured to output a signal indicative of the electrical charge.
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Abstract
An electrical device includes at least one graphene quantum capacitance varactor. In some examples, the graphene quantum capacitance varactor includes an insulator layer, a graphene layer disposed on the insulator layer, a dielectric layer disposed on the graphene layer, a gate electrode formed on the dielectric layer, and at least one contact electrode disposed on the graphene layer and making electrical contact with the graphene layer. In other examples, the graphene quantum capacitance varactor includes an insulator layer, a gate electrode recessed in the insulator layer, a dielectric layer formed on the gate electrode, a graphene layer formed on the dielectric layer, wherein the graphene layer comprises an exposed surface opposite the dielectric layer, and at least one contact electrode formed on the graphene layer and making electrical contact with the graphene layer.
30 Citations
19 Claims
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1. A sensor comprising:
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a graphene quantum capacitance varactor having a graphene layer, wherein capacitance of the graphene layer changes in response to electrical charge collected proximate to the graphene layer; and a readout circuit responsive to the capacitance of the graphene layer and configured to output a signal indicative of the electrical charge. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A sensor comprising:
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a graphene quantum capacitance varactor having a graphene layer, wherein capacitance of the graphene layer changes in response to electrical charge external to the graphene layer, and a multi-finger structure comprising at least two gate electrode fingers, and wherein each of the at least two gate electrode fingers is electrically connected in parallel with the others of the at least two gate electrode fingers.
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13. A sensor having a graphene quantum capacitance varactor comprising:
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an insulator layer defining a plurality of fingers, wherein a first finger of the plurality of fingers extends in a first direction within the insulator layer, and wherein a second finger of the plurality of fingers extends in a second direction substantially opposite to the first direction; a gate electrode formed in the plurality of fingers; a dielectric layer formed on the gate electrode; a first graphene layer positioned over the first finger, wherein the first graphene layer comprises a first exposed surface opposite the dielectric layer; a second graphene layer positioned over the second finger, wherein the second graphene layer comprises a second exposed surface opposite the dielectric layer; at least one contact electrode formed on the first and second graphene layers and making electrical contact with the first and second graphene layers; and glucose-sensitive molecules attached to at least one of the first exposed surface or the second exposed surface. - View Dependent Claims (14)
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15. A wireless sensing system comprising:
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a sensor comprising; a graphene quantum capacitance varactor comprising a graphene layer, wherein the capacitance of the graphene layer changes in response to electrical charge external to the graphene layer, and a first inductor electrically connected to the graphene quantum capacitance varactor, wherein the first inductor and the graphene quantum capacitance varactor form an LC oscillator circuit having a resonant frequency responsive to a sense charge collected by the graphene quantum capacitance varactor; and a second inductor electromagnetically coupled to the first inductor to produce a signal responsive to the resonant frequency of the LC oscillator.
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16. A method of forming a sensor, the method comprising:
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forming a graphene quantum capacitance varactor comprising a graphene layer, wherein the capacitance of the graphene layer changes in response to a sense charge collected proximate to the graphene layer upon exposure to a sample; and coupling the graphene layer to a readout circuit responsive to the capacitance of the graphene layer and configured to output a signal indicative of the sense charge. - View Dependent Claims (17, 18, 19)
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Specification