Bistable nanoswitch
A non-volatile bistable nano-electromechanical switch is provided for use in memory devices and microprocessors. The switch employs carbon nanotubes as the actuation element. A method has been developed for fabricating nanoswitches having one single-walled carbon nanotube as the actuator. The actuation of two different states can be achieved using the same low voltage for each state.
1. A non-volatile, bistable nanoswitch device comprising:
an actuation element comprising one or more single-walled or multi-walled carbon nanotube spanning a gap between first and second electrical terminals exposed on a surface of an insulating nanosubstrate, the gap comprising a first nanoscale channel and a second nanoscale channel;
a third electrical terminal exposed on the surface of the nanosubstrate and electrically connected to a conductive layer situated within the first channel;
a fourth electrical terminal exposed on the surface of the nanosubstrate and electrically connected to a conductive layer situated within the second channel;
wherein application of a first voltage between the first and third terminals causes the nanotube to form an electrical contact with the conductive layer in the first channel, whereby state 1 is activated by forming a non-volatile electrical connection between the first and third terminals; wherein application of a second voltage between the second and fourth terminals causes the nanotube to form an electrical contact with the conductive layer in the second channel, whereby state 2 is activated by forming a non-volatile electrical connection between the second and fourth terminals; and wherein activation of state 1 is accompanied by inactivation of state 2 , and activation of state 2 is accompanied by inactivation of state 1 .
2. The nanoswitch device of claim 1 , wherein the insulating substrate comprises silicon dioxide or silicon nitride.
3. The nanoswitch device of claim 1 , wherein the insulating substrate further comprises an oxide layer deposited onto said surface.
4. The nanoswitch device of claim 1 , wherein the conductive layer comprises gold, chromium, silver, or a mixture thereof.
5. The nanoswitch device of claim 1 , wherein a first voltage above a first threshold causes the nanotube to form an electrical contact with the conductive layer in the first channel.
6. The nanoswitch device of claim 1 , wherein a second voltage above a second threshold causes the nanotube to form an electrical contact with the conductive layer in the second channel.
7. The nanoswitch device of claim 1 , wherein the first and second threshold voltages are each about 3 volts.
8. The nanoswitch device of claim 1 , wherein the actuation element consists essentially of a bundle of from about 1 to about 10 single-walled carbon nanotubes.
9. The nanoswitch device of claim 8 , wherein the actuation element consists essentially of one single-walled carbon nanotube.
10. The nanoswitch device of claim 1 , wherein the nanoscale channels each have a width of at least about 20 nm and a length of at least about 100 nm.
11. An electrical component comprising one or more nanoswitch devices according to claim 1 .
12. The electrical component of claim 11 which is a memory device, microprocessor, latch, flip-flop, register, or relay.
13. A method of actuating the nanoswitch device of claim 1 , the method comprising the steps of:
providing the nanoswitch device of claim 1 in state 1 , having a non-volatile electrical connection between the first and third terminals;
applying a voltage between the second and fourth terminals;
removing the voltage between the second and fourth terminals;
whereby a non-volatile electrical connection is established between the second and fourth terminals, and the electrical connection between the first and third terminals is abolished.
14. The method of claim 13 , wherein the voltage applied between the second and fourth terminals is about 3 volts.
15. A method of actuating the nanoswitch device of claim 1 , the method comprising the steps of:
providing the nanoswitch device of claim 1 in state 2 , having a non-volatile electrical connection between the second and fourth terminals;
applying a voltage between the first and third terminals;
removing the voltage between the first and third terminals;
whereby a non-volatile electrical connection is established between the first and third terminals, and the electrical connection between the second and fourth terminals is abolished.
16. The method of claim 15 , wherein the voltage applied between the first and third terminals is about 3 volts.