Investigation of analog memristive switching of iron oxide nanoparticle assembly between Pt electrodes

Abstract

The analog memristive switching of iron oxide (γ-Fe2O3) nanoparticle assembly was investigated. The γ-Fe2O3 nanoparticles were chemically synthesized with ∼10 nm in diameter and assembled to be a continuous layer as a switching element in Pt/nanoparticles/Pt structure. It exhibited the analog switching that the resistance decreased sequentially as repeating −V sweeps and pulses while increased as applying +V. The capacitance-voltage curves presenting hysteresis with flatband voltage shift and distortion of their shapes with respect to the applied voltage supported the redistribution of space charges in nanoparticle assembly that might induce resistive switching. The polarity-dependent analog resistance change proportional to pulse voltage, time, and number of pulses was analogy to potentiation and depression of adaptive synaptic motion.

Analog Memristive and Memcapacitive Characteristics of Pt-Fe2O3 Core-Shell Nanoparticles Assembly on p+-Si Substrate

“…Despite of the loss, the retention property is superior to the short-term memory loss in the range from seconds to tens of minutes in biological systems (e.g. human brain) [34] as well as that with -Fe 2 O 3 NPs in our previous study [18], thanks to the use of Pt-Fe 2 O 3 core-shell NPs storing the charges in deep Pt cores and leading to long-term memory of synaptic characteristics. …”

“…The NPs have large surface and interfacial states that effectively provides trapping and hopping sites for charge transport and consequently influences on the capacitance and resistance change. We have previously demonstrated that -Fe 2 O 3 NPs assembly exhibited the polarity-dependent analog memristive characteristics [18], unlike the FeO x thin films typically showing digital-type unipolar switching through formation and rupture of conducting filaments [19] and bipolar switching through redox reaction [20]. Compared to the assembly of -Fe 2 O 3 NPs [18], the use of Pt-Fe 2 O 3 core-shell NPs having Pt cores has a benefit of more stable charging in deep level of Pt cores [21].…”

“…We have previously demonstrated that -Fe 2 O 3 NPs assembly exhibited the polarity-dependent analog memristive characteristics [18], unlike the FeO x thin films typically showing digital-type unipolar switching through formation and rupture of conducting filaments [19] and bipolar switching through redox reaction [20]. Compared to the assembly of -Fe 2 O 3 NPs [18], the use of Pt-Fe 2 O 3 core-shell NPs having Pt cores has a benefit of more stable charging in deep level of Pt cores [21]. Also, the applied electric field is concentrated in metallic Pt cores inside the insulating Fe 2 O 3 shell [22], so the memristive and memcapacitive characteristics associated with charge trapping is thought to be facilitated by using Pt-Fe 2 O 3 core-shell NPs.…”

Analog Switching and Artificial Synaptic Behavior of Ag/SiOx:Ag/TiOx/p++-Si Memristor Device

“…In contrast to digital switching, the continuous conductance tunability in memristors bears some similarities with a biological synapse, which is the basic cellular unit for the learning and memory functions in the human brain [18]. In several memristor devices, the analog conductance changes used to emulate the weight modulation of biological synapses have been realized [19,20].…”

DFT+USimulation of theTi4O7−Padilha1, Rocha2, Dalpian3 2015Phys. Rev. Applied150150View full textAdd to dashboardCite

“…[4] There are reports of a wide range of materials (particularly metal oxides) which show this memristive effect. [5][6][7][8][9][10][11][12][13][14] Although the switching mechanism, and the origin of the different resistance states has not been completely elucidated, it is generally believed that the presence of oxygen deficient phases plays a major role in the memristive effect. [15] Within the possible materials, TiO 2 is one of the most studied ones.…”