The HR-TEM images in Fig. 3a and b show the microstructures of
the CNTs and CNCs, respectively. Unlike the crystalline structure of
CNTs, our CNCs showed a composite structure with some nano
graphite crystallites (indicated with arrows and circles) embedded
in the amorphous matrix.
In recent years, several research teams, including us, have used
CNCs as the cathode material to fabricate field emission lamp (FEL)
devices [26,27]. The results of these previous studies have indicated