Memristors are candidates for scaled-down brain-inspired neuromorphic circuits because of their simple two-terminal (2T) device geometry and in-memory computation capability which can overcome the power limitations of the von Neumann architecture. Crossbar circuits based on 2T memristors typically require an additional unit such as a transistor for individual node selection. Although highly effective, this approach significantly increases circuit footprint and manufacturing complexity. A memristive device with gate-tunable synaptic functionalities would not only integrate selection functionality at the cell level but could also lead to enriched on-demand learning schemes. Here, a three-terminal (3T) mixed-halide perovskite memristive device with gate-tunable synaptic functions operating at low potentials is demonstrated [1]. The device operation was controlled by both the drain (V_D) and gate (V_G) potentials, with an extended endurance of >2000 cycles and a state retention of >5000 s. Applying a voltage (V_set) of 20 V across the 50 μm channel switches its conductance from a high-resistance-state (HRS) to low-resistance-state (LRS). A memristive switching mechanism is proposed that is supported by current injection models through a Schottky barrier and Kelvin probe force microscopy data. The simultaneous application of a V_G potential is found to further modulate the channel conductance and reduce the operating V_set to 2 V, thus requiring a low electric field of 400 V/cm, which is by a factor of 50× less compared to state-of-the-art literature reports. Gate-tunable retention, endurance and synaptic functionalities were demonstrated, further highlighting the beneficial effect of V_G on device operation. By setting appropriate current compliance current, the devices can be operated in volatile I-V switching mode demonstrating extended endurance characteristics [2]. In this diffusive memristor mode, the devices exhibit pulse-amplitude and -frequency characteristics allowing linear conductivity modulation opening the path for the implementation of a leaky integrate-and -fire (LIF) neuron with light and gate tunable functions.

[1] Rogdakis, K.; Chatzimanolis, K.; Psaltakis, G.; Tzoganakis, N.; Tsikritzis, D.; Anthopoulos, T. D.; Kymakis, E Mixed-halide perovskite memristors with gate-tunable functions operating at low switching electric fields. Adv. Electron. Mater.2023, 2300424

[2] Rogdakis K., et al. Manuscript in preparation.