Strong influence of the applied or self-induced (i.e. self-biasing) electric field on the alignment, orientation and structures wan found in the carbon nano-structure deposition process. This study applied microwave-plasma eleetron-cyelotron-resonance CVD (ECR-CVD) technique for carbon nano-structure deposition. The deposited structures and properties were characterized with SEM and field emission I-V measurements. The result shows that a negative dc bias applied on the substrate is a necessary condition. In this condition, all carbon nanostructures were well aligned and perpendicular to the substrate surfaces and independent to the plasma/gas flowing directions. Interestingly, when applied an additional electric field near the substrate surface by a guiding metal plate, the CNT growth direction could be manipulated from perpendicular to nearly parallel to the substrate surface. Moreover, a rattan-like CNT would form when prolonging the deposition lime or increasing the plasma carbon concentration. These novel nanostructures are expected to have high potential in energy storage, field emission display, nanoelectronics and gas sensing applications accordingly.
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