Author(s): Lo An-Ya | Liu Shang-Bin | Kuo Cheng-Tzu
Journal: Nanoscale Research Letters
ISSN 1931-7573
Volume: 5;
Issue: 9;
Start page: 1393;
Date: 2010;
Original page
Keywords: CNTs | Growth mechanism | Base-growth | Tip-growth | CVD
ABSTRACT
Abstract To improve the understanding on CNT growth modes, the various processes, including thermal CVD, MP-CVD and ECR-CVD, have been used to deposit CNTs on nanoporous SBA-15 and Si wafer substrates with C2H2 and H2 as reaction gases. The experiments to vary process parameter of ΔT, defined as the vector quantities of temperature at catalyst top minus it at catalyst bottom, were carried out to demonstrate its effect on the CNT growth mode. The TEM and TGA analyses were used to characterize their growth modes and carbon yields of the processes. The results show that ΔT can be used to monitor the temperature gradient direction across the catalyst nanoparticle during the growth stage of CNTs. The results also indicate that the tip-growth CNTs, base-growth CNTs and onion-like carbon are generally fabricated under conditions of ΔT > 0,
Journal: Nanoscale Research Letters
ISSN 1931-7573
Volume: 5;
Issue: 9;
Start page: 1393;
Date: 2010;
Original page
Keywords: CNTs | Growth mechanism | Base-growth | Tip-growth | CVD
ABSTRACT
Abstract To improve the understanding on CNT growth modes, the various processes, including thermal CVD, MP-CVD and ECR-CVD, have been used to deposit CNTs on nanoporous SBA-15 and Si wafer substrates with C2H2 and H2 as reaction gases. The experiments to vary process parameter of ΔT, defined as the vector quantities of temperature at catalyst top minus it at catalyst bottom, were carried out to demonstrate its effect on the CNT growth mode. The TEM and TGA analyses were used to characterize their growth modes and carbon yields of the processes. The results show that ΔT can be used to monitor the temperature gradient direction across the catalyst nanoparticle during the growth stage of CNTs. The results also indicate that the tip-growth CNTs, base-growth CNTs and onion-like carbon are generally fabricated under conditions of ΔT > 0,
