Rapid generation of carbon filament structures of controlled geometries at low temperatures
Exemplary embodiments provide methodologies for generating structures of filamentous carbon (or carbon filaments) with controlled geometries. In one exemplary embodiment of forming the carbon filament structure, a metal template can be exposed to a fuel rich gaseous mixture to form a carbon filament structure at an appropriate gas flow and/or at an appropriate temperature on the metal template. The metal template can have one or more metal surfaces with controlled geometries. Carbon filament structures can then be grown on the metal surfaces having corresponding geometries (or shapes) in the growth direction. The carbon filament structure can be two or three dimensional and can have high density. In various embodiments, the metal template can be removed to leave a self-supporting carbon filament structure.
1. A method for preparing a filament structure comprising:
exposing a template to a fuel rich gaseous mixture comprising one or more hydrocarbons and at least one oxidizer, wherein the fuel rich gaseous mixture has a flow rate chosen to produce a turbulent flow over the template; and
heating the fuel rich gaseous mixture and the template to a temperature sufficient to form a woven carbon filament film on the template, wherein the template comprises a catalytic metal and the woven carbon filament film comprises a non-graphitic carbon structure.
2. The method of claim 1 , further comprising forming a patterned metal template comprising one or more metal surfaces, wherein the filament structure is grown on each metal surface mimicking a shape of the metal surface in the growth direction.
3. The method of claim 1 , wherein the metal template comprises a finely divided catalytic metal.
4. The method of claim 3 , wherein the catalytic metal comprises a noble metal.
5. The method of claim 3 , wherein the finely divided catalytic metal comprises palladium, platinum, nickel, colbalt, rhodium, or mixtures thereof.
6. The method of claim 1 , wherein the metal template is selected from the group consisting of a foam, a lattice, a patterned array, a thin film, a wire and a monolith.
7. The method of claim 1 , further comprising controlling an exposure time of the metal template to the fuel rich gaseous mixture so as to control a growth length of the filament structure.
8. The method of claim 1 , wherein the metal template at least partially covers a substrate that comprises a non-catalytic metal, a ceramic, or a semiconductor.
9. The method of claim 1 , further comprising incorporating epoxy into the formation of the filament structure.
10. The method of claim 1 , wherein the fuel rich gaseous mixture and the template surface are heated at the temperature of about 100° C. to about 1000° C.
11. The method of claim 1 , further comprising removing the metal template and leaving the formed filament structure.
12. The method of claim 1 , further wherein a planar graphitic structure is formed on a portion of the metal template.
13. The method of claim 1 , wherein the fuel rich gaseous mixture further comprises a chemically inert gas.
14. The method of claim 13 , wherein the hydrocarbon comprises ethylene; the oxidizer comprises oxygen; and the chemically inert gas comprises argon, nitrogen, or helium.
15. A method for preparing a filament coated article comprising:
placing a template into a container, wherein the template comprises one or more catalytic metal surfaces that at least partially cover the template;
introducing a fuel rich gaseous mixture into the container, wherein the fuel rich gaseous mixture comprises one or more hydrocarbons and at least one oxidizer and has a flow rate chosen to produce a turbulent flow over the template; and
heating the template to a temperature chosen to at least partially combust the one or more hydrocarbons, thereby depositing a woven carbon filament film on each of the one or more catalytic metal surfaces of the template, wherein the woven carbon filament film comprises a non-graphitic carbon structure.
16. The method of claim 15 , further comprising preparing the template having the one or more catalytic metal surfaces and pre-treating the one or more catalytic metal surfaces prior to the introduction of the gaseous mixture.
17. The method of claim 16 , wherein the preparation of the template comprises:
forming a silicon oxide film on a silicon wafer; and
depositing a catalytic metal palladium film on the formed silicon oxide film, wherein the palladium film is finely divided and has a thickness of about 500 angstroms.
18. The method of claim 15 , further comprising controlling a shape of the filament film in the deposition direction by mimicking a shape of an underlying catalytic metal surface.
19. The method of claim 15 , further comprising a cooling process to freeze the deposition of the filament film.
20. The method of claim 15 , further comprising depositing a carbon filament film to fill a via structure between levels of a multi-level integrated circuit.
21. The method of claim 15 , further comprising depositing a filament film on a large part of a vehicle comprising a truck, an automobile, a ship, a spaceship, and an airplane.
22. A method for preparing a filament coated article comprising:
forming a patterned metal template and placing the patterned metal template into a container comprising a tube furnace;
pre-treating the patterned metal template in the container;
introducing a fuel rich gaseous mixture comprising one or more hydrocarbons and oxygen into the container with a flow rate chosen to produce a turbulent flow;
heating the patterned metal template to a temperature chosen to at least partially combust the one or more hydrocarbons, whereby a patterned woven carbon filament film is deposited on the patterned metal template, wherein the template comprises a catalytic metal and the woven carbon filament film comprises a non-graphitic carbon structure; and
cooling the container to freeze the deposition of the filament film.
23. The method of claim 22 , wherein the fuel rich gaseous mixture further comprises a chemically inert gas comprising argon, nitrogen, or helium.