Fast Spiking of a Mott VO<sub>2</sub>-Carbon Nanotube Composite Device.

Bohaichuk, Stephanie M; Kumar, Suhas; Pitner, Greg; McClellan, Connor J; Jeong, Jaewoo; Samant, Mahesh G; Wong, H-S Philip; Parkin, Stuart S P et al. · Nano Lett · 2019

basic_science · Level V

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Abstract

The recent surge of interest in brain-inspired computing and power-efficient electronics has dramatically bolstered development of computation and communication using neuron-like spiking signals. Devices that can produce rapid and energy-efficient spiking could significantly advance these applications. Here we demonstrate direct current or voltage-driven periodic spiking with sub-20 ns pulse widths from a single device composed of a thin VO<sub>2</sub> film with a metallic carbon nanotube as a nanoscale heater, without using an external capacitor. Compared with VO<sub>2</sub>-only devices, adding the nanotube heater dramatically decreases the transient duration and pulse energy, and increases the spiking frequency, by up to 3 orders of magnitude. This is caused by heating and cooling of the VO<sub>2</sub> across its insulator-metal transition being localized to a nanoscale conduction channel in an otherwise bulk medium. This result provides an important component of energy-efficient neuromorphic computing systems and a lithography-free technique for energy-scaling of electronic devices that operate via bulk mechanisms.