All-Solid-State Synaptic Transistors with High-Temperature Stability Using Proton Pump Gating of Strongly Correlated Materials

Abstract

Designing energy-efficient artificial synapses with adaptive and programmable electronic signals is essential to effectively mimic synaptic functions for brain-inspired computing systems. Here, we report all-solid-state three-terminal artificial synapses that exploit proton-doped metal–insulator transition in a correlated oxide NdNiO3 (NNO) channel by proton (H+) injection/extraction in response to gate voltage. Gate voltage reversibly controls the H+ concentration in the NNO channel with facile H+ transport from a H+-containing porous silica electrolyte. Gate-induced H+ intercalation in the NNO gives rise to nonvolatile multilevel analogue states due to H+-induced conductance modulation, accompanied by significant modulation of the out-of-plane lattice parameters. This correlated transistor operated by a proton pump shows synaptic characteristics such as long-term potentiation and depression, with nonvolatile and distinct multilevel conductance switching by a low voltage pulse (≥ 50 mV), with high energy efficiency (∼1 pJ) and tolerance to heat (≤150 °C). These results will guide the development of scalable, thermally-stable solid-state electronic synapses that operate at low voltage.

Ion‐Gated Transistor: An Enabler for Sensing and Computing Integration

“…Given the feature of flexible operation for tuning the channel conductance, IGTs are favorable for artificial synaptic devices and thereby being used for neuromorphic computing. [137][138][139][140][141][142][143][144][145][146][147][148][149][150][151][152][153] Figure 6. a) Alcohol detection by simply breathing on the OECT-based sensors.…”

“…[ 109–136 ] Given the feature of flexible operation for tuning the channel conductance, IGTs are favorable for artificial synaptic devices and thereby being used for neuromorphic computing. [ 137–153 ]…”

Deep Proton Insertion Assisted by Oxygen Vacancies for Long‐Term Memory in VO2 Synaptic Transistor

“…As δ increases in VO 2− δ channels, the H + is incorporated into a much “deeper” region from the electrolyte/VO 2− δ interfaces (Figure 2e); these results clearly demonstrate that the deep penetration of H + during application of V G is facilitated by preformed oxygen vacancies in VO 2− δ layers; H + are inserted more deeply into the VO 2− δ lattice than into the VO 2 lattice, so the VO 2− δ lattice retains more residual (or trapped) H + than the VO 2 lattice does. [ 6,9,15 ]…”

“…[ 2 ] Unlike the devices using transport of oxygen ion (via oxygen vacancies), [ 2,3 ] H + as an extrinsic defect can be externally inserted into a target VO 2 channels to alter conductivity and induce phase transition between insulating and metallic phase without disrupting the crystal lattice framework [ 6,10,13 ] ; this smallest and lightest ions can increase the switching speed at low voltage in insertion transistors. [ 4,6,10,15 ]…”

Perovskite neural trees

“…Here, we show that tree-like structures can be experimentally realized at room temperature in strongly correlated rare-earth perovskite nickelates (ReNiO 3 , where Re is a rare-earth ion), a class of quantum materials whose electrical properties are largely dominated by the strong interactions among electrons in them [28][29][30] . For example, in NdNiO 3 and SmNiO 3 , prior studies have shown that hydrogen doping results in several orders of magnitude change in electrical resistance via modifying electron occupancy of the Ni orbitals 31,32 . When hydrogen molecules are split by a catalytic electrode into hydrogen atoms and doped into the rare-earth perovskite nickelate lattice, the electron from the hydrogen atom is injected to the Ni e g orbital, while the proton resides in interstitial sites.…”