Crossover from synaptic to neuronal functionalities through carrier concentration control in Nb-doped SrTiO₃-based organic ferroelectric tunnel junctions

The development of neuromorphic architectures depends on the engineering of new functional materials and material interfaces. Here, we present a study on organic ferroelectric tunnel junctions (FTJs) comprising a metal/ferroelectric/semiconductor stack with varying charge carrier density in the semiconducting electrode and demonstrate fast, volatile switching behavior when the bound polarization charges in the tunnel barrier are insufficiently screened. The manipulation of ferroelectric polarization and depolarization dynamics in our FTJs through pulse magnitude, duration, and delay time constitutes a controlled transition from synaptic behavior to integrate-and-fire neuronal activity. This ability to tune the response of a single memristor device via charge carrier optimization opens pathways for the design of smart electronic neurons.