Abstract
Small diameter single wall carbon nanotubes are desirable for various physical and electrical properties of carbon nanotubes. Here, we report the sensitivities of parameters and the optimal conditions for small diameter carbon nanotube growth by chemical vapor deposition (CVD). These results were obtained using the Taguchi method, which is commonly used to find the optimal parameters of various processes. The possible parameter ranges given by the experimental equipment and laboratory conditions, we attempted several times to determine the proper ranges, using photoluminescence (PL) imaging to determine the exact positions of suspended carbon nanotubes on the quartz substrates after synthesis. The diameters of the carbon nanotubes were then determined from the radial breathing modes (RBM) using Raman spectroscopy with a 785nm wavelength laser. Among the 4 major parameters listed above, we concluded that the temperature was the most significant parameter in determining carbon nanotube diameter, hydrogen flow rate was the second most significant, the ethanol and argon gas flow rate was the third, and finally time was the least significant factor.
Highlights
Carbon nanotubes have been widely researched since their discovery in 1991 by Iijima.[1]
PL imaging was carried out using a thermoelectrically cooled InGaAs array (Xenics, Inc.) in conjunction with a defocused 785nm laser. These images were used to identify the exact positions of these suspended single walled nanotube (SWNT), and the radial breathing mode (RBM) frequency was measured by Raman spectroscopy to determine the diameter of each SWNT
The diameter of SWNTs is inversely proportional to the frequency of the RBM, TABLE I
Summary
Carbon nanotubes have been widely researched since their discovery in 1991 by Iijima.[1] During this time, carbon nanotubes (CNTs) have been utilized for a variety of applications. The electronic structure of carbon nanotubes is strongly dependent on their diameter.[2] The smallest diameter single walled nanotube (SWNT) that is stable was theoretically predicted to be as small as 0.4nm, as reported by Sawada et al.[3] There have been other reports of small diameter SWNTs by several other research groups.[4,5,6] Making SWNTs with small diameters has been investigated for many years.[7,8,9] The previous research of Arjmandi et al investigated chemical vapor deposition (CVD) synthesis of carbon nanotubes based on equipment designed and developed within their group.[10] While these studies report various recipes of how to make small diameter nanotubes, they do not investigate the sensitivities of each growth parameter for SWNTS with small diameter. We report the sensitivities of these growth parameters for making SWNTs with small diameters
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
