An Energy‐Efficient, BiFeO3‐Coated Capacitive Switch with Integrated Memory and Demodulation Functions

A capacitive switching behavior is observed in a Si3N4/p-Si-based metal-insulator-semiconductor (MIS) structure due to the electron tunneling at the Si3N4/p-Si interface. A BiFeO3 (BFO) layer is deposited on Si3N4/p-Si by pulsed laser deposition technique to obtain the memcapacitive effect as the distribution of positive charges in the Si3N4 layer can be stabilized by the polarization charge of the ferroelectric BFO coating layer. The capacitive switching behavior of the Al/BFO/Si3N4/p-Si/Au MIS structure is also sensitive to both intensity and wavelength of the illumination, which offers the possibility to create a photodetector for both intensity and color detection. Thus, the presented device has the potential application for future information storage and visible light communications. As an example, a photocapacitive demodulator with capability of decoding both wavelength and intensity information of the incident light is demonstrated.