Cost-effective method for fabricating carbon nanotube network transistors by reusing a 99% semiconducting carbon nanotube solution.

Carbon nanotubes (CNTs) are one-dimensional materials that have been proposed to replace silicon semiconductors and have been actively studied due to their high carrier mobility, high current density, and high mechanical flexibility. Specifically, highly purified, pre-separated, and solution-processed semiconducting CNTs are suitable for mass production. These CNTs have advantages, such as room-temperature processing compatibility, while enabling a fast and straightforward manufacturing process. In this paper, CNT network transistors were fabricated on a total of five 8 inch wafers by reusing a highly purified and pre-separated 99% semiconductor-enriched CNT solution. The results confirmed that the density of semiconducting CNTs deposited on the five selected wafers was notably uniform, even though the CNT solution was reused up to four times after the initial CNT deposition. Moreover, there was no significant degradation in the key CNT network transistor metrics. Therefore, we believe that our findings regarding this CNT reuse method may provide additional guidance in the field of wafer-scale CNT electronics and may contribute strongly to the development of practical device applications at an ultralow cost.

Wafer-scale carbon nanotube network transistors.

Highly purified, preseparated semiconducting carbon nanotubes (CNTs) hold great potential for high-performance CNT network transistors due to their high electrical conductivity, high mechanical strength, and room-temperature processing compatibility. In this paper, we report our recent progress on CNT network transistors integrated on an 8-inch wafer. We observe that the key device performance parameters of CNT network transistors at various locations on an 8-inch wafer are highly uniform and that the device yield is impressive. Therefore, this work validates a promising path toward mass production and will make a significant contribution to the future field of wafer-scale CNT electronics.

Flexible carbon nanotube Schottky diode and its integrated circuit applications.

Carbon nanotubes (CNTs), a low-dimensional material currently popular in industry and academia, are promising candidates for addressing the limits of existing semiconductors. In particular, CNTs are attractive candidates for flexible electronic materials due to their excellent flexibility and potential applications. In this work, we demonstrate a flexible CNT Schottky diode based on highly purified, preseparated, solution-processed 99% semiconducting CNTs and an integrated circuit application using the CNT Schottky diodes. Notably, the fabricated flexible CNT diode can greatly modulate the properties of the contact formed between the semiconducting CNT and the anode electrode via the control gate bias, exhibiting a high rectification ratio of up to 2.5 × 105. In addition, we confirm that the electrical performance of the CNT Schottky diodes does not significantly change after a few thousand bending/releasing cycles of the flexible substrate. Finally, integrated circuit (IC) applications of logic circuits (OR and AND gates) and an analog circuit (a half-wave rectifier) were presented through the use of flexible CNT Schottky diode combinations. The correct output responses are successfully achieved from the circuit applications; hence, we expect that our findings will provide a promising basis for electronic circuit applications based on CNTs.