416
N. Shimoi
(a)
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
0.0
200.0
400.0
600.0
800.0
1000.0
1200.0
Loading FE current density / A cm -2
Loading time / hours
High crystallized SWCNTs
Annealed SWCNTs at over 10 -2 Pa
(Ref.)
Un- treated SWCNTs
(b)
Fig. 29.2 a Buckypaper made by pressing a solution of dispersed SWCNTs or MWCNTs. b The
radioactive half-time of FE current density up to 1000 h at an applied DC voltage. The loading time
when employing high crystallized SWCNTs against the initial FE current density was over 1000 h
without the attenuation of FE current
for the high crystallized SWCNTs after annealing studied in Fig. 29.1c. Although
the SWCNTs were found to be highly crystalline, this result particularly confirms
that the treated SWCNTs have high crystallization of the carbon network.
To show the importance of employing high crystallized SWCNTs in electrical
devices, the increased effect of the high crystallization of SWCNTs was examined
with high crystallized SWCNTs and un-annealed SWCNTs with crystal defects on
their electrical properties as FE electron sources.
29.3 Measurements and compression
29.3.1 Durability of SWCNTs Loading Field Electron
Emission Lifetime
The cathode electrodes prepared as Buckypaper made by pressing of solutiondispersed and filtered SWCNTs were used to measure FE lifetimes, as shown in
Fig. 29.2. Fig. 29.2b shows the FE lifetimes up to 1000 h for high crystallized