Method and apparatus for attaching nanostructure-containing material onto a sharp tip of an object and related articles

1. A method of attaching carbon nanotubes and/or nanowires onto a sharp tip by an electrophoresis process, the method comprising the successive steps of:

providing an object with a sharp, pointed tip;

forming a suspension containing at least one of a carbon nanotube or nanowire, wherein the suspension has a surface;

immersing an electrode in the suspension;

placing the sharp tip of the object perpendicular to and directly above the surface of the suspension;

applying a voltage between the immersed electrode and the sharp tip;

moving the sharp tip toward the surface of the suspension until electrical contact is established between the immersed electrode and the sharp tip;

allowing current to pass between the immersed electrode and the sharp tip for a predetermined amount of time, wherein the carbon nanotube or nanowire attaches to the sharp tip and remains permanently attached after the application of voltage is discontinued; and

raising the sharp tip above the surface of the suspension after expiration of the predetermined amount of time.

2. The method of claim 1 , comprising:

monitoring the current between the immersed electrode and the sharp tip to determine when electrical contact between the electrode and tip is established.

3. The method of claim 1 , further comprising:

annealing the sharp tip with attached nanotube or nanowire.

4. The method of claim 1 , wherein forming a suspension containing carbon nanotubes or nanowires further comprises selectively adding a charger to the liquid medium.

5. The method of claim 1 , wherein the nanotubes comprise at least one of carbon, BxNy, CxByNz, and MS2, wherein M=tungsten, molybdenum, or vanadium oxide.

6. The method of claim 1 , wherein the nanowires comprise at least one of an elemental metal, an elemental or a compound semiconductor, an oxide, a carbide, a nitride, and a chalcogenide.

7. The method of claim 1 , comprising attaching an individual nanotube, nanotube bundle, or nanowire to the sharp tip at a contact point of the sharp tip with the suspension.

8. The method of claim 1 , wherein the object with a sharp tip comprises a plurality of sharp tips, wherein the plurality of sharp tips are arranged to concurrently be in contact with the suspension, whereby the nanostructure-containing material attaches to each of the sharp tips.

9. The method of claim 1 , wherein the electrophoresis process is a dielectrophoresis method where an alternating-current voltage is applied between the sharp tip and the immersed electrode.

10. The method of claim 1 , wherein either an individual nanotube or a single nanowire is attached to the sharp tip after the electrophoresis process.

11. The method of claim 1 , wherein multiple nanotubes, multiple nanowires, or a mixture of nanotubes and nanowires are attached to the sharp tip after the electrophoresis process.

12. The method of claim 1 , wherein the sharp tip with the attached nanotube or nanowire used as a probe for an atomic force microscope, a probe for a scanning tunneling microscope, or a point electron field emission source.

13. The method of claim 1 , wherein allowing current to pass between the immersed electrode and the sharp tip for a predetermined amount of time comprises the carbon nanotube or nanowire forming a protrusion or bundle on the sharp tip wherein the carbon nanotube or nanowire remains permanently attached even after application of voltage is discontinued.