
138 CHAPTER 5 Engineered carbon nanotube field emission devices
Figure 5.9 shows the growth rate (R) as a function of reciprocal (absolute) tem-
perature for various PE-CVD and T-CVD synthesized nanotubes, nanobers, and
graphene [135,192,204]. Data has been linearly tted according to the Arhenius
relation:
R DS
E
kT
∝
−
oo
a
B
exp
where T is the growth temperature, k
B
is Boltzmann’s constant, and D
o
and S
o
denote the
carbon diffusivity and solubility prefactors [135]. E
a
is estimated by linear interpolation
and gradient extrapolation [200]. For ITO/Ni and ITO/Fe nanobers (closed/open red
squares) the activation energies are 0.51 ± 0.15 ...