Alignment of Carbon Nanotubes inside the Fibers Through Interfacial Interaction of Nanoparticles for Using as Cathode for Field Emission

Alignment of carbon nanotubes (CNTs) inside the CNT fiber is very important for the fast electron movement through CNTs. We utilized nanoparticles, such as ZnO for the alignment of CNTs and described how semiconducting ZnO can act as an alignment agent in carbon nanotubes (CNTs) fibers. Due to the alignment of CNTs through the ZnO nanoparticles linking groups, the CNTs inside the fibers were equally distributed by the attraction of bonding forces into sheet-like bunches, such that any applied mechanical breaking load was equally distributed to each CNT inside the fiber, making them mechanically robust against breaking loads. Although semi-conductive ZnO nanoparticles were used here, the electrical conductivity of the aligned CNT fiber was comparable to bare CNT fibers, suggesting that the total electron movement through the CNTs inside the aligned CNT fiber is not disrupted by the insulating behavior of ZnO nanoparticles. Due to the high electrical, mechanical, and thermal properties of CNT fiber, it is a good candidate as field emitter. For using CNT fiber as cathode for sheet beam, CNT fiber further was converted to the sheet structure, which are more important for getting sheet nanoparticles incorporated on CNT surfaces, but it still showed lower current. So, for the increase of emission current, need good contact between substrate and CNTs or need to use substrate free techniques. In addition, electrical, mechanical, and thermal properties of the CNTs should be improved for field emission application. The alignment of CNTs are beneficial for many different applications including field emission [2] and also increases electrical conductivity with mechanical properties.