Fig. 3
Reproduced with permission from Ref. [141]. Copyright 2017, John Wiley and Sons
Experimental demonstrations of filament-free switching memristors. a–c A nonfilamentary memristor based on the ferroelectric effect. Clear lattice fringe from the device structure (a), I-V hysteresis (b), and the modulation of the barrier structure according to the polarization direction (c). Reproduced with permission from Ref. [106]. Copyright 2020, Springer Nature. d–f A phase transition-based nonfilamentary memristor. Cross-sectional TEM images of MoS2 2H phase and lithiated MoS2 1 T phase (d), I-V switching curves accompanying first negative sweep (e), and AFM topography and schematics of Li+ ion distribution for device states (f). Reproduced with permission from Ref. [119]. Copyright 2019, Springer Nature. g–i A Filling-controlled Mott transition-based nonfilamentary memristor. Cross-sectional TEM images of the device structure g, I-V switching curves for different device fabrication conditions (h), and the switching mechanism based on bandgap and Fermi level change of GdNiO3−x layer (i).