Event Information
Property Control of Single Walled Carbon Nanotubes and Their Devices
- Abstract:
Since their discovery by Iijima, single walled carbon nanotubes have displayed potential in a variety of promising applications such as transistors, sensors, light emitters, logic circuits, and so forth because of their unique structural, mechanical, and electronic properties. Single walled carbon nanotubes can be either semiconducting or metallic depending on the helicity and diameter. To fulfill their potential in large scale, the charility, diameter and allocation of the nanotubes must be controlled. However, the technological hurdle of synthesizing specific nanotubes or modifying their properties after growth has hampered the further development of carbon nanotube applications because the synthesis yields a mixture of carbon nanotubes with different properties. In this study, we demonstrate the control of single walled carbon nanotube properties as well as their device performance by extensive studies in direct controllable synthesis of nanotubes or post-growth treatment using metal decoration.
Various efforts have been developed trying to obtain high quality, narrow diameter distribution, and aligned single walled carbon nanotubes. One approach is the control in the direct synthesis of carbon nanotubes in terms of their diameter, uniformity, and allocation by chemical vapor deposition method. The employed approaches include using uniform nanoparticles with specific sizes as catalysts, using laser irradiation to grow uniform and high quality nanotubes, changing the gas flow pattern to obtain different density, and using the external force including flow, topography and substrate guidance to grow horizontally aligned nanotubes. Importantly, purely semiconducting horizontally aligned nanotube arrays on quartz have been illustrated. In addition, the channel length, nanotube density and diameter effect on the field effect transistor performance are demonstrated both by experiments and modeling. Other than this method, the properties of carbon nanotubes can be manipulated by Pd decoration after growth. Two novel applications including carbon nanotube film conductivity improvement and nanostructure growth catalysis are developed as well as the decoration mechanism was explained.
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