Iridium oxide nanotubes and method for forming same
View Patent ↗A method is provided for forming iridium oxide (IrOx) nanotubes. The method comprises: providing a substrate; introducing a (methylcyclopentadienyl)(1,5-cyclooctadiene)iridium(I) precursor; introducing oxygen as a precursor reaction gas; establishing a final pressure in the range of 1 to 50 Torr; establishing a substrate, or chamber temperature in the range of 200 to 500 degrees C.; and using a metalorganic chemical vapor deposition (MOCVD) process, growing IrOx hollow nanotubes from the substrate surface. Typically, the (methylcyclopentadienyl)(1,5-cyclooctadiene)iridium(I) precursor is initially heated in an ampule to a first temperature in the range of 60 to 90 degrees C., and the first temperature is maintained in the transport line introducing the precursor. The precursor may be mixed with an inert carrier gas such as Ar, or the oxygen precursor reaction gas may be used as the carrier.
1. A method for forming iridium oxide (IrOx) nanotubes, the method comprising:
providing a substrate with a surface;
introducing a (methylcyclopentadienyl)(1,5-cyclooctadiene)iridium(I) precursor as follows:
initially heating the precursor to a first temperature in the range of 60 to 90 degrees C.;
maintaining the first temperature in the transport line introducing the precursor; and
mixing the precursor with a carrier gas;
introducing oxygen as a precursor reaction gas; and,
using a metalorganic chemical vapor deposition (MOCVD) process, growing IrOx hollow nanotubes from the substrate surface.
2. The method of claim 1 further comprising:
establishing a final pressure in the range of 1 to 50 Torr.
3. The method of claim 2 further comprising:
prior to introducing the precursor, establishing a base pressure in the range of 1×10 −8 to 1×10 −3 Torr.
4. The method of claim 3 wherein introducing oxygen as a precursor reaction gas includes adding oxygen to increase the base pressure to the final pressure; and,
wherein introducing precursor includes introducing precursor alter the final pressure has been reached.
5. The method of claim 3 wherein establishing a final pressure includes simultaneously adding oxygen and precursor, increasing the base pressure to the final pressure.
6. The method of claim 1 wherein mixing the precursor with a carrier gas includes mixing with a carrier gas selected from the group including Ar and oxygen.
7. The method of claim 1 wherein introducing the (methylcyclopentadienyl) (1,5-cyclooctadiene)iridium(I) precursor includes introducing the precursor and carrier gas at a flow rate in the range of 50 to 500 standard centimeter cube per minute (sccm).
8. The method of claim 1 wherein introducing oxygen as a precursor reaction gas includes introducing oxygen at a flow rate in the range of 50 to 500 sccm.
9. The method of claim 2 wherein establishing a final pressure in the range of 1 to 50 Torr includes establishing a final pressure in the range of 30 to 50 Torr.
10. The method of claim 1 further comprising:
establishing a substrate temperature in the range of 200 to 500 degrees C.
11. The method of claim 1 wherein growing IrOx hollow nanotubes from the substrate surface includes growing nanotubes with square-shaped diameters.
12. The method of claim 1 wherein growing IrOx hollow nanotubes from the substrate surface includes growing nanotubes with a diameter in the range of 100 Å to 1 micron.
13. The method of claim 1 wherein growing IrOx hollow nanotubes from the substrate surface includes growing nanotubes having an aspect ratio (length to width) in the range of 1:1 to 50:1.
14. The method of claim 1 wherein growing IrOx hollow nanotubes from the substrate surface includes:
growing a cluster of adjacent nanotips with ends;
merging the nanotip ends; and
growing the cluster of merged ends, creating a closed tube structure.
15. The method of claim 14 wherein merging the nanotip ends includes merging four ends from the cluster.
16. The method of claim 1 wherein providing a substrate with a surface includes providing a substrate made from a material selected from the group including TiN, TaN, Ti, Ta, Si, and SiO2.
17. The method of claim 1 wherein growing IrOx hollow nanotubes from the substrate surface includes growing nanotubes having a length in the range of 500 Å to 2 microns.
18. An iridium oxide (IrOx) nanotube, the nanotube comprising:
a plurality of clustered IrOx nanotips with joined ends;
a hollow cavity formed between the nanotips; and
wherein a IrOx hollow nanotube is formed by joining 4 nanotip ends.
19. The nanotubes of claim 18 wherein the hollow nanotube has a square-shaped diameter.
20. The nanotube of claim 18 wherein the hollow nanotube has a diameter in the range of 100 Å to 1 micron.
21. The nanotube of claim 18 wherein the hollow nanotube has an aspect ratio (length to width) in the range of 1:1 to 50:1.
22. The nanotube of claim 18 wherein the nanotubes have a length in the range of 500 Å to 2 microns.
23. A method for forming iridium oxide (IrOx) nanotubes, the method comprising:
providing a substrate with a surface;
introducing a (methylcyclopentadienyl) (1,5-cyclooctadiene)iridium(I) precursor; and
using a metalorganic chemical vapor deposition (MOCVD) process, growing IrOx hollow nanotubes from the substrate surface as follows:
growing a cluster of adjacent nanotips with ends;
merging the nanotip ends; and
growing the duster of merged ends, creating a closed tube structure.