Carbon nanotube growth on metallic substrate using vapor phase catalyst delivery
A chemical vapor deposition (CVD) method using a vapor phase catalyst of directly growing aligned carbon nanotubes on a metal surfaces. The method allows for fabrication of carbon nanotube containing structures that exhibit a robust carbon nanotube metal junction without a pre-growth application of solid catalytic materials to the metal surface or the use of solder or adhesives in a multi-step fabrication process.
1. A method for making carbon nanotubes, comprising:
providing a substrate having a metal surface;
providing a vapor phase mixture comprised of a nanotube forming precursor and a nanotube growth catalyst onto the metal surface of the substrate; and
directly growing the carbon nanotubes on the metal surface of the substrate such that the carbon nanotubes are substantially aligned in a direction perpendicular to said metal surface of the substrate;
wherein:
said nanotube growth catalyst is a metal catalyst vapor, and said metal surface of the substrate comprises a nickel, chromium and iron alloy;
the carbon nanotubes comprise multiwalled carbon nanotubes;
the multiwalled carbon nanotubes are grown at a temperature of 600-1100° C.; and
the metal surface of the substrate is not coated with a nanotube growth catalyst prior to initiating nanotube growth.
2. The method of claim 1 , wherein the nanotube forming precursor comprises xylene.
3. The method of claim 1 , wherein the nanotube growth catalyst comprises ferrocene.
4. The method of claim 1 , wherein the vapor phase mixture comprises a mixture of xylene and ferrocene.
5. The method of claim 1 , wherein the nickel, chromium and iron alloy comprises about 72% nickel.
6. The method of claim 1 , further comprising incorporating the carbon nanotubes directly grown on the metal surface into a field emission device comprising an electron emitting material, wherein the electron emitting material comprises the carbon nanotubes directly grown on the metal surface.
7. The method of claim 1 , further comprising incorporating the carbon nanotubes directly grown on the metal surface into a double layer capacitor comprising two electrodes separated by a separator, wherein at least one electrode comprises the carbon nanotubes directly grown on the metal surface.
8. A method of growing carbon nanotubes on a metal surface of a substrate, the method comprising:
exposing the metal surface to a vapor phase mixture comprising a nanotube-forming precursor and a nanotube-growth catalyst; and
directly growing the carbon nanotubes on the metal surface such that the carbon nanotubes are substantially aligned in a direction perpendicular to the metal surface;
wherein the nanotube-growth catalyst is a metal catalyst vapor; and
wherein the metal surface of the substrate comprises a nickel, chromium and iron alloy.
9. The method of claim 8 , wherein the nickel, chromium and iron alloy comprises about 72% nickel.