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

A capacitive switching behavior is observed in a Si 3 N 4 /p-Si-based metal–insulator–semiconductor (MIS) structure due to the electron tunneling at the Si 3 N 4 /p-Si interface. A BiFeO 3 (BFO) layer is deposited on Si 3 N 4 /p-Si by pulsed laser deposition technique to obtain the memcapacitive effect as the distribution of positive charges in the Si 3 N 4 layer can be stabilized by the polarization charge of the ferroelectric BFO coating layer. The capacitive switching behavior of the Al/BFO/Si 3 N 4 /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.