Protons: Critical Species for Resistive Switching in Interface‐Type Memristors

• Published in: Advanced electronic materials 2023-01, Vol.9 (1), p.n/a
• Main Authors: Kunwar, Sundar, Somodi, Chase Bennett, Lalk, Rebecca A., Rutherford, Bethany X., Corey, Zachary, Roy, Pinku, Zhang, Di, Hellenbrand, Markus, Xiao, Ming, MacManus‐Driscoll, Judith L., Jia, Quanxi, Wang, Haiyan, Joshua Yang, J., Nie, Wanyi, Chen, Aiping
• Format: Article
• Language: English
• Subjects: Au/Nb:STO; Behavior; charge trapping/detrapping; Electrodes; Gases; Gold; High resistance; Hysteresis; Interfaces; interface‐type memristors; Memory devices; Memristors; Metal oxides; moisture effect; Moisture resistance; Protons; resistive switching; Switching
• ISSN: 2199-160X; 2199-160X
• DOI: 10.1002/aelm.202200816

Interface‐type (IT) resistive switching (RS) memories are promising for next generation memory and computing technologies owing to the filament‐free switching, high on/off ratio, low power consumption, and low spatial variability. Although the switching mechanisms of memristors have been widely studied in filament‐type devices, they are largely unknown in IT memristors. In this work, using the simple Au/Nb:SrTiO3 (Nb:STO) as a model Schottky system, it is identified that protons from moisture are key element in determining the RS characteristics in IT memristors. The Au/Nb:STO devices show typical Schottky interface controlled current–voltage (I–V) curves with a large on/off ratio under ambient conditions. Surprisingly, in a controlled environment without protons/moisture, the large I–V hysteresis collapses with the disappearance of a high resistance state (HRS) and the Schottky barrier. Once the devices are re‐exposed to a humid environment, the typical large I–V hysteresis can be recovered within hours as the HRS and Schottky interface are restored. The RS mechanism in Au/Nb:STO is attributed to the Schottky barrier modulation by a proton assisted electron trapping and detrapping process. This work highlights the important role of protons/moisture in the RS properties of IT memristors and provides fundamental insight for switching mechanisms in metal oxides‐based memory devices. Metal/Nb:SrTiO3 Schottky devices exhibit interface‐controlled resistive switching (RS) characteristics with high on/off ratios, good memory retention, and high endurance cycles. This work reveals that the RS and Schottky barrier modulation are dominantly controlled by protons (from ambient moisture) assisted charge trapping/detrapping processes at the metal/Nb:SrTiO3 interface.