High-power switching device based on field emission mechanism fabricated using highly crystalline single-walled carbon nanotubes

Since the Great East Japan Earthquake in 2011, there has been a growing interest in energy conservation all over the world. To build a society centered on renewable energy, it is essential to obtain inexpensive and stable renewable energy, and completely eliminate energy loss in the energy utilization system for conserving energy optimally. Towards the construction of an energy-saving low-carbon society, we have utilized the field emission (FE) characteristics of highly crystalline single-walled carbon nanotubes (HC-SWCNTs), which are synthesized by arc discharge, purified, and annealed at high temperatures, to form an excellent electron emission layer with high current density and high durability. The thin films containing HC-SWCNTs exhibit electrical properties that result in almost no heat generation at high current densities (i.e., high power densities). When the thin films fabricated in this research were used in a power switching device, the FE characteristics of HC-SWCNTs as an electron source in the device were applied to switch the ampere-order currents on and off. Owing to their high crystallinity, SWCNTs exhibit potentials close to the ideal conductive characteristics, and their performance is expected to meet the requirements of high-power density, zero energy loss, and high-frequency responses, even when compared with power devices fabricated using semiconductors, for example, SiC and GaN. Therefore, the purpose of this research is to establish a high-power-density and low-energy-loss thin-film formation technology and to develop a high-performance switching device.