Infiltrated carbon nanotubes
Described herein are examples of systems, methods, apparatuses, and devices which include a carbon nanotube structure. The carbon nanotube structure may include a first carbon nanotube with a first top surface and a first bottom surface. The carbon nanotube structure may include a second carbon nanotube vertically aligned with the first carbon nanotube. The second carbon nanotube may include a second top surface and a second bottom surface. The first carbon nanotube and the second carbon nanotube may be infiltrated with carbon by a mixture that is flowing. The mixture may include a first amount of ethylene and a second amount of hydrogen. The carbon nanotube structure may include a thin film extending along the first bottom surface and the second bottom surface.
1 . An apparatus, comprising:
a first carbon nanotube, comprising:
a first top surface; and
a first bottom surface;
a second carbon nanotube vertically aligned with the first carbon nanotube, the second carbon nanotube comprising:
a second top surface; and
a second bottom surface, wherein the first carbon nanotube and the second carbon nanotube are infiltrated with carbon by a mixture that is flowing and having a temperature between 800 and 950 degrees Celsius, the mixture comprising:
a first amount of ethylene between 150 standard cubic centimeter per minute (sccm) and 200 sccm; and
a second amount of hydrogen between 100 sccm and 200 sccm, wherein the hydrogen is 25-75% of the flow, wherein infiltrating the first carbon nanotube and the second carbon nanotube with carbon causes the first carbon nanotube and the second carbon nanotube to have carbon deposits formed thereon and to not delaminate from a substrate during cooling subsequent the infiltrating; and
a thin film extending along the first bottom surface and the second bottom surface, wherein the thin film is suspended between the first carbon nanotube and the second carbon nanotube.
2 . The apparatus of claim 1 , wherein the thin film comprises a carbon film.
3 . The apparatus of claim 1 , further comprising a sacrificial layer disposed between the thin film and both the first bottom surface of the first carbon nanotube and the second bottom surface of the second carbon nanotube, wherein the sacrificial layer comprises a thickness of 1-1000 microns.
4 . The apparatus of claim 1 , wherein the first carbon nanotube and the second carbon nanotube are further infiltrated with an additional material other than carbon by chemical vapor deposition, and the thin film comprises a silicon dioxide film, an aluminum oxide film, or a boron carbide film.
5 . The apparatus of claim 1 , further comprising a yield tensile strength of 110 megapascals (MPa) and a Young's modulus of 6 gigapascals (GPa).
6 . The apparatus of claim 1 , wherein the thin film comprises carbon to increase resistance to bending of a transmission electron microscopy (TEM) grid.
7 . A method, comprising:
growing a carbon nanotube (CNT) structure on a substrate, wherein the CNT structure comprises:
a first CNT; and
a second CNT, wherein the first CNT and the second CNT are vertically aligned, wherein, during growing the first CNT or the second CNT includes:
flowing the ethylene at approximately fifteen parts per minute; and
flowing the hydrogen at approximately forty parts per minute; and
infiltrating bulk carbon between the first CNT and the second CNT, the bulk carbon adhering to the first CNT and the second CNT, wherein the infiltrating comprises heating the first CNT and the second CNT in the presence of a gas mixture to a temperature between approximately 800 to 950° C., wherein:
the gas mixture comprises:
ethylene flowing at approximately one part per minute; and
hydrogen flowing at approximately two parts per minute;
the gas mixture is flowed over the first CNT and the second CNT for an amount of time ranging from 1 minute to 24 hours; and
the infiltrating strengthens the carbon nanotube structure such that when the carbon nanotubes are cooled, the carbon nanotubes do not delaminate from the substrate; and
cooling the first CNT and the second CNT in the presence of argon to approximately 300° C.
8 . The method of claim 7 , wherein growing the first CNT and the second CNT comprises:
growing the first CNT on a first iron catalyst site deposited on the substrate; and
growing the second CNT on a second iron catalyst site deposited on the substrate,
wherein the growing comprises:
heating the substrate to between 60° and 900° C.; and
flowing ethylene and hydrogen over the substrate for 10 minutes.
9 . The method of claim 7 , wherein:
the substrate comprises a silicon substrate; and
the silicon substrate is heated to 750° C.
10 . The method of claim 7 , further comprising removing the substrate via etching, wherein the etching is performed in 300 Watt oxygen plasma at 100 mTorr.
11 . The method of claim 7 , wherein the first CNT or the second CNT comprises a carbon density of approximately 1% of a volume of the first CNT or the second CNT.
12 . The method of claim 7 , comprising flowing 25 sccm of argon over the first CNT and the second CNT during the cooling.
13 . The method of claim 7 , further comprising burning out the first CNT and the second CNT in an oxygen-containing environment to remove the carbon deposited on the first CNT and the second CNT during the infiltration.