Hon Hai Precision Industry Co., Ltd. (Tu-Cheng, Taipei Hsien, TW) and Tsinghua University (Beijing, CN) received U.S. Patent 7,700,048 for a chemical vapor deposition apparatus to quickly and inexpensively manufacture an array of super-aligned carbon nanotubes using an iron catalyst on a quartz-boat region.
According to inventors Kai-Li Jiang (Beijing, CN) and Shou-Shan Fan (Beijing, CN), the reaction chamber has a first gas inlet configured for introducing a carbon source gas and a carrier gas into the chamber, a second gas inlet is configured for introducing a hydrogen gas into the chamber, a guiding tube in communication with the second gas inlet, and a gas outlet. The quartz-boat region is configured for accommodating a quartz boat for supporting a substrate; wherein the guiding tube extends inwardly a distance sufficient to enable the majority of the introduced hydrogen gas that reaches the substrate not to react with the carbon source gas.
The quartz boat is disposed in the reaction chamber, the quartz boat has an obliquely oriented portion for accommodating the substrate. The reaction chamber is substantially tubular in shape. The carrier gas includes at least one of the noble gases or nitrogen gas. The carbon source gas is selected from the group consisting of ethylene, methane, acetylene, ethane, and any combination of them.
Compared with conventional CVD devices for making carbon nanotube arrays, the device s has the following advantages. Firstly, the present apparatus can perform at a relatively low temperature, for example, in the range from 600 to 700 degree C. In the preferred embodiment of the apparatus, an array of bundled and super-aligned carbon nanotubes can be synthesized at temperatures in the range from 620 to 690 degree C. Secondly, growth speed and yield of carbon nanotubes are both improved. After growing carbon nanotubes for 30 to 60 minutes, the carbon nanotube array has a height of a few hundred micrometers to a few millimeters. Thirdly, the apparatus and method for growing carbon nanotubes is inexpensive. A carrier gas and a carbon source gas of the preferred method can be inexpensive argon and acetylene. A catalyst can be inexpensive iron.
Compared with conventional CVD devices for making carbon nanotube arrays, the device s has the following advantages. Firstly, the present apparatus can perform at a relatively low temperature, for example, in the range from 600 to 700 degree C. In the preferred embodiment of the apparatus, an array of bundled and super-aligned carbon nanotubes can be synthesized at temperatures in the range from 620 to 690 degree C. Secondly, growth speed and yield of carbon nanotubes are both improved. After growing carbon nanotubes for 30 to 60 minutes, the carbon nanotube array has a height of a few hundred micrometers to a few millimeters. Thirdly, the apparatus and method for growing carbon nanotubes is inexpensive. A carrier gas and a carbon source gas of the preferred method can be inexpensive argon and acetylene. A catalyst can be inexpensive iron.
FIG. 1 is a schematic view of an Tsinghua University and Hon Hai apparatus for making an array of carbon nanotubes in accordance with a preferred embodiment of theapparatus for CNT production.


Referring to FIGS. 2 and 3, a SEM image and a TEM image of the multi-walled carbon nanotube array formed by the present apparatus are shown. It can be seen that the carbon nanotubes in the carbon nanotube array are highly bundled and super-aligned. The height of the carbon nanotube array is about 300 micrometers.
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