Cryogenic behavior of NbO2 based threshold switching devices as oscillation neurons

This Letter investigates the cryogenic behavior of NbO2 threshold switching devices. Pt/NbO2/Pt devices are demonstrated to be well functional as threshold switching devices at ultra-low temperature (4 K). When the temperature decreases, the OFF-state resistance of NbO2 increases and the switching voltage increases. With the extracted characteristics of NbO2 ranging from 4 K to 300 K, we continue to study the neuromorphic system using the crossbar array with resistive memories as resistive synapses and NbO2 as oscillation neurons at different temperatures through SPICE simulation. The simulation results show that the oscillation systems could still work properly at 4 K. The oscillation amplitude decreases as temperature increases. The oscillation frequency depends on both the temperature and the input voltage.