Experimental Demonstration of CeO₂-Based Tunable Gated Memristor for RRAM Applications

Abstract

This paper reports the fabrication and characterization of a cerium dioxide (CeO 2 )-based gated memristor with metal electrodes. The fabricated device exhibits memristive behavior, owing to the intrinsic oxygen vacancies originating from the utilized solution combustion method of synthesizing CeO 2 . By configuration of the biasing, this memristor can serve as either a conventional two-terminal (2T) memristor or a three-terminal (3T) gated memristor, offering the capability to adjust the set voltage (V SET ). Electrical assessments affirm that this constructed memristor boasts an exceptionally high R OFF /R ON ratio (∼10 5 ) and a low V SET of 0.756 V. At a compliance current (I CC ) of 20 mA, the device displays a remarkably low activation slope of 3.5 mV/decade. Additionally, it demonstrates outstanding cyclic stability, reproducibility, and data retention even after 10 5 cycles. In the three-terminal, or 3T, configuration, manipulation of the gate voltage can precisely control the V SET . We elucidate the operational theory of this gated memristor, focusing on electroformation. Numerical simulations illustrating the two-dimensional electric field profiles of the device support the findings from physical experiments, affirming the validity of the electroformation concept within the active layer. The ability to adjust V SET through the back gate bias enhances its utility in analog VLSI and data conversion. Furthermore, its impressive R OFF /R ON ratio positions it as an ideal candidate for resistive random access memory.

Dual Exciton Polarization in Bipolar CeO2–x Nanocrystals Controlled by Defect-Based Redox Processes

“…Cerium dioxide (or ceria) has a cubic (fluorite-type) crystal structure and exhibits a unique combination of ionic (oxide and proton), − and electrical (n- and p-type) ,− conductivities. This complex conductivity makes CeO 2 an attractive candidate material for an electrolyte in solid oxide fuel cells (SOFCs), electrocatalysts for rechargeable metalair batteries, and for memristor system technologies, including resistive random-access memory (RRAM). Ionic conductivity is due to oxygen vacancies, which are created either by substitutional doping of CeO 2 with trivalent lanthanide cations (e.g., Gd 3+ , Sm 3+ , or Pr 3+ ) or the presence of Ce 3+ (self-doping by reduction of Ce 4+ ): 2 Ce 4 + + O 2 − → 2 Ce 3 + + V O · · + 1 2 O 2 …”