Carbon nanotubes for the selective transfer of heat from electronics
Under one aspect, a method of cooling a circuit element includes providing a thermal reservoir having a temperature lower than an operating temperature of the circuit element; and providing a nanotube article in thermal contact with the circuit element and with the reservoir, the nanotube article including a non-woven fabric of nanotubes in contact with other nanotubes to define a plurality of thermal pathways along the article, the nanotube article having a nanotube density and a shape selected such that the nanotube article is capable of transferring heat from the circuit element to the thermal reservoir.
1. A heat conduction element for cooling a circuit element, comprising:
a thermal reservoir having a temperature lower than an operating temperature of said circuit element; and
a nanotube article in thermal contact with said circuit element and said thermal reservoir;
wherein said nanotube article comprises a non-woven fabric of nanotubes in contact with other nanotubes to define a plurality of thermal pathways along said nanotube article;
wherein said nanotube article has a nanotube density and a geometry selected such that said nanotube article is capable of transferring heat from said circuit element to said thermal reservoir.
2. The heat conduction element of claim 1 wherein said nanotube article is formed by depositing pre-formed nanotubes on a surface so as to form a non-woven fabric of nanotubes.
3. The heat conduction element of claim 2 wherein depositing said pre-formed nanotubes comprises at least one of spin-coating pre-formed nanotubes and spray-coating pre-formed nanotubes.
4. The heat conduction element of claim 1 wherein said nanotube article is formed by growing nanotubes on a surface so as to form a non-woven fabric of nanotubes.
5. The heat conduction element of claim 1 wherein said geometry of said nanotube article is defined lithographically.
6. The heat conduction element of claim 5 wherein defining the shape of the nanotube article lithographically comprises forming a non-woven fabric of nanotubes and subsequently removing selected portions of that non-woven fabric of nanotubes in accordance with the shape.
7. The heat conduction element of claim 1 wherein said nanotube article is formed conformably said circuit element.
8. The heat conduction element of claim 1 wherein said nanotube article has a substantially planar shape.
9. The heat conduction element of claim 1 further comprising a substrate element having a substantially planar major surface and a feature not in the plane of the major surface, and wherein said nanotube article substantially conforms to said feature.
10. The heat conduction element of claim 1 further comprising support elements under said nanotube article, said support elements defining a gap over which said nanotube article is suspended.
11. The heat conduction element of claim 1 wherein the nanotube density and geometry are selected such that the nanotube article is capable of transferring heat from the circuit element to the thermal reservoir at a pre-defined rate selected to maintain the circuit element below a pre-specified temperature.
12. The heat conduction element of claim 1 wherein said pre-specified temperature comprises an upper limit of a normal operating temperature.
13. The heat conduction element of claim 1 wherein said nanotube article has a pre-defined composition.
14. The heat conduction element of claim 13 wherein said pre-defined composition includes single-walled nanotubes.
15. The heat conduction element of claim 13 wherein said pre-defined composition includes multi-walled nanotubes.
16. The heat conduction element of claim 1 wherein said circuit element comprises at least a portion of an integrated circuit.
17. The heat conduction element of claim 1 wherein said circuit element comprises an encapsulation material.
18. The heat conduction element of claim 1 wherein said thermal reservoir comprises a heat sink.
19. The heat conduction element of claim 18 wherein said heat sink comprises a plurality of fins that radiate heat.
20. The heat conduction element of claim 1 further comprising a thermally conductive material between and in thermal contact with each of said nanotube article and said circuit element.