Bifunctional device with high-energy storage density and ultralow current analog resistive switching

Abstract

A bifunctional device capable of simultaneously achieving dielectric energy storage and resistive switching is first designed and fabricated based on a conventional metal–insulator–metal (MIM) structure. Typically, Al/TaOx/Pt structure shows a high breakdown strength up to 5.07 MV cm−1 and a relatively high-energy density of 27.6 J cm−3. Meanwhile, the leakage current of the MIM structure is at the sub-nanoampere level and exhibits the typical characteristic of analog switching under an applied voltage of about 12 volts. The energy density and the switching current in the developed integrated MIM structure are comparable to the corresponding performances in discrete binary oxides capacitors with linear dielectric and oxide-based memristors, respectively. Furthermore, synaptic functions with short-term and long-term plasticities can be realized. Both of the device properties are found to be correlated to the role of the AlOx interfacial layer between the Al electrode and the dielectric layer, which provides the possibility of coupling between these two functions coexisting in the MIM structure. The prototypical bifunctional device offers a great prospect for multifunctional energy and neuromorphic applications.