Ultra-sensitive detection techniques
View Patent ↗Techniques for ultra-sensitive detection are provided. In one aspect, a detection device is provided. The detection device comprises a source; a drain; a nanowire comprising a semiconductor material having a first end clamped to the source and a second end clamped to the drain and suspended freely therebetween; and a gate in close proximity to the nanowire.
1. A detection device comprising:
a source;
a drain;
a nanowire comprising a semiconductor material having a first end clamped to the source and a second end clamped to the drain and suspended freely therebetween; and
a gate separated from the nanowire by a distance of up to about ten nanometers.
2. The device of claim 1 , wherein a length of the nanowire suspended between the source and the drain is between about 100 nanometers and about 200 nanometers.
3. The device of claim 1 , wherein the nanowire has a diameter of between about 15 nanometers and about 30 nanometers.
4. The device of claim 1 , wherein the gate has a width that is less than a length of the nanowire suspended between the source and the drain.
5. The device of claim 1 , further comprising a dielectric substrate between at least a portion of the gate and one or more of the source and the drain, wherein the dielectric substrate has a thickness of up to about ten nanometers and comprises one or more of silicon dioxide, hafnium oxide and air.
6. The device of claim 1 , wherein the nanowire comprises one or more of germanium, silicon, galliumarsenide, indiumphosphide, graphene, organic semiconductors and Pentacene.
7. The device of claim 1 , wherein at least a portion of a surface of the nanowire has at least one functional group thereon comprising one or more of an amine, a thiol and a carboxyl group.
8. The device of claim 1 , wherein at least a portion of a surface of the nanowire is charge-sensitized.
9. The device of claim 1 , wherein the nanowire is configured to actuate in response to a voltage being applied to the gate at a given frequency, wherein the given frequency equals a resonance frequency of the nanowire.
10. An integrated circuit comprising:
at least one detection device comprising:
a source;
a drain;
a nanowire comprising a semiconductor material having a first end clamped to the source and a second end clamped to the drain and suspended freely therebetween;
a gate in close proximity to the nanowire; and
at least one frequency modulation demodulator in circuit with the at least one detection device, wherein the at least one frequency modulation demodulator is configured to detect a source-drain current modulation in the at least one detection device.
11. The integrated circuit of claim 10 , further comprising:
at least one transimpedance amplifier electrically connected to the drain;
at least one bandpass filter electrically connected to the transimpedance amplifier; and
at least one automatic gain control circuit electrically connected to the bandpass filter.
12. The method of claim 10 , wherein the actuating step further comprises the steps of:
applying a voltage to the gate at a given frequency to induce a modulated electric field between the gate and the nanowire at the given frequency wherein the given frequency equals a resonance frequency of the nanowire; and
using the modulated electric field to exert a force on the nanowire at the given frequency.
13. The method of claim 10 , wherein the detecting step further comprises the steps of:
using a modulation in distance between the nanowire and the gate, brought about by actuating the nanowire, to induce a modulation of capacitance between the nanowire and the gate; and
using the modulation of capacitance between the nanowire and the gate to induce a source-drain current modulation at a given frequency, wherein the given frequency equals a resonance frequency of the nanowire.
14. A mass detection device comprising:
a source;
a drain;
a nanowire comprising a semiconductor material having a first end clamped to the source and a second end clamped to the drain and suspended freely therebetween; and
a gate separated from the nanowire by a distance of up to about ten nanometers, wherein the gate has a width that is less than a length of the nanowire suspended between the source and the drain, and wherein the nanowire is configured to actuate in response to a voltage being applied to the gate at a given frequency.
15. A molecular detection device comprising:
a source;
a drain;
a nanowire comprising a semiconductor material having a first end clamped to the source and a second end clamped to the drain, wherein at least a portion of a surface of the nanowire is charge-sensitized; and
a gate, at least a portion of which is separated from one or more of the source and the drain by a dielectric substrate, and wherein the gate is separated from the nanowire by a distance of up to about ten nanometers.
16. A method of operating a mass detection device comprising a source; a drain; a nanowire comprising a semiconductor material having a first end clamped to the source and a second end clamped to the drain and suspended freely therebetween; and a gate separated from the nanowire by a distance of up to about ten nanometers, wherein the gate has a width that is less than a length of the nanowire suspended between the source and the drain, the method comprising the steps of:
actuating the nanowire; and
detecting mechanical resonance of the nanowire.
17. A method of operating a molecular detection device comprising a source; a drain; a nanowire comprising a semiconductor material having a first end clamped to the source and a second end clamped to the drain, wherein at least a portion of a surface of the nanowire is charge-sensitized; and a gate, at least a portion of which is separated from one or more of the source and the drain by a dielectric substrate, the method comprising the steps of:
generating free electrical charge in the nanowire, rendering the nanowire conductive;
exposing the molecular detection device to an ambient containing at least one compound; and
detecting reactions between the charge-sensitized surface of the nanowire and the compound.
18. The method of claim 17 , wherein the generating step further comprises the step of:
applying a voltage to the gate to generate free electrical charge in the nanowire, wherein the voltage is greater than a threshold voltage of the nanowire.
19. The method of claim 17 , wherein the detecting step further comprises the steps of:
inducing a change in a source-drain current, the change in the source-drain current indicating the reactions between the charged-sensitized surface of the nanowire and the compound.