ALD-Driven Ultra-Thin ZnO Channels for Flexible Electrolytic Neuromorphic Devices

Ultra-thin (4-nm) ZnO films, grown by atomic layer deposition (ALD) at 250 °C with a rate of 2 Å/cycle, enable stable electrical performance in corresponding devices. Low-frequency noise measurements combined with Kelvin probe force microscopy reveal that these ALD-ZnO channels possess the ability to trap carriers and couple ions with electrons. Integrating a sodium-ion electrolyte, the neuromorphic device successfully demonstrates essential synaptic plasticity while reducing the energy consumption per synaptic event by an order of magnitude. Consequently, 2-level encryption and a 5-bit reservoir computing system are experimentally implemented, achieving information concealment and pattern classification, respectively. Furthermore, an artificial nociceptor, constructed by cascading alarm units, exhibits sensitive responses to stimuli as short as 0.1 s. This study demonstrates the significant potential of ALD-fabricated ultra-thin channels for advanced neuromorphic applications.