Current Modulation by Optoelectric Control of Ferroelectric Domains

Optoelectric control of domains is likely to pave the foundation for optoferroelectric devices. This work reports the combined effect of light and low-voltage electric bias for optoelectric control of ferroelectric domains in a semiconducting ceramic material—KNBNNO ((K_0.5Na_0.5)NbO₃ doped with 2 mol % Ba(Ni_0.5Nb_0.5)O_3−δ). The effect is utilized to achieve two orders of magnitude amplification in electrical response, asymmetric AC modulation, and domain velocities of 30 000 nm s^–1 with ultralarge domain switching areas of over 30 μm in fractions of a second. The charge injection due to light illumination on this material causes the tuning of material conductivity and acts as a virtual electrode. Based on this mechanism, a proof of concept for a monolithic ferroelectric light-effect transistor with a source and drain as electrical contacts with light acting as a virtual gate is demonstrated. This is likely to offer a potential solution to the scaling limit of conventional three-terminal transistors. The same device is also demonstrated to work as a photodiode, a half-wave rectifier, and an electrical output modulator.