Nociceptive Memristor

Abstract

The biomimetic characteristics of the memristor as an electronic synapse and neuron have inspired the advent of new information technology in the neuromorphic computing. The application of the memristors can be extended to the artificial nerves on condition of the presence of electronic receptors which can transfer the external stimuli to the internal nerve system. In this work, nociceptor behaviors are demonstrated from the Pt/HfO₂/TiN memristor for the electronic receptors. The device shows four specific nociceptive behaviors; threshold, relaxation, allodynia, and hyperalgesia, according to the strength, duration, and repetition rate of the external stimuli. Such nociceptive behaviors are attributed to the electron trapping/detrapping to/from the traps in the HfO₂ layer, where the depth of trap energy level is ≈0.7 eV. Also, the built-in potential by the work function mismatch between the Pt and TiN electrodes induces time-dependent relaxation of trapped electrons, providing the appropriate relaxation behavior. The relaxation time can take from several milliseconds to tens of seconds, which corresponds to the time span of the decay of biosignal. The material-wise evaluation of the electronic nociceptor in comparison with other material, which did not show the desired functionality, Pt/Ti/HfO₂/TiN, reveals the importance of careful material design and fabrication.

Nociceptor behaviors are demonstrated from the Pt/HfO₂/TiN memristor as the electrical nociceptor. The memristor shows the characteristics of allodynia, and hyperalgesia, which are typical behaviors of the biological nociceptor. Such nociceptive responses are attributed to the threshold switching and resistance switching of the memristor, which are caused by electron trapping/detrapping to/from the traps in the HfO₂ layer.

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