Carbon Nanotube-Based High-Current Nanoscale Air-Channel Electronic Devices for Low-Power Ultrafast Electronics

Abstract

Nanoscale air-channel electronic devices (NAEDs) have gained intensive attention recently due to their great potential as fundamental building blocks in future low-power ultrafast electronics. Despite considerable progress on low-power ultrafast characteristics, practical applications of NAEDs are being hindered by the low working current generally in the range of 0.01–20 μA. This unattainable high current is mainly due to the weak emission of electrons from a seriously limited effective emission area in conventional low-voltage field-emission (LV-FE) electron sources of currently existing NAEDs. Here, we present a high-current LV-FE electron source for an NAED, which consists of high-aspect-ratio carbon nanotubes (CNTs) and large-specific surface-area microstructures. The emission current density is increased exponentially by compensating for the field-screening effect between adjacent CNTs with the additional field-enhancement effect derived from underlying microstructures. Due to the simultaneously enlarged effective emission area, milliampere-level high current is achieved by optimizing the structure of the CNT-based LV-FE electron source. CNTs have been directly grown on well-selected microstructures with the matched feature size and improved interface contact, experimentally demonstrating an optimized LV-FE electron source with a high current of 6 mA. The feasibility of achieving high-current performance with a subpicosecond ultrafast response at a low turn-on voltage has been confirmed by configuring NAED with a CNT-based LV-FE electron source. This achievement has great potential to promote future practical applications in low-power ultrafast electronics.