Surface redox induced bipolar switching of transition metal oxide films examined by scanning probe microscopy

Lee, Min Hwan; Kim, Kyung Min; Song, Seul Ji; Rha, Sang Ho; Seok, Jun Yeong; Jung, Ji Sim; Kim, Gon−Ho; Yoon, Jung Ho; Hwang, Cheol Seong

doi:10.1007/s00339-011-6266-7

Cited by 24 publications

(17 citation statements)

References 10 publications

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“…Lee et al analyzed a 60 nm thick polycrystalline TiO 2 on a Pt bottom electrode with a Pt‐coated tip by conductive AFM measurements. In addition to the asymmetric contact geometry, they discussed the effect of possible adsorbed hydrocarbons on the TiO 2 surface …”

Section: Resultsmentioning

confidence: 99%

Resistive Switching of Individual, Chemically Synthesized TiO₂Nanoparticles

Schmidt

Hoffmann‐Eifert

Zhang

et al. 2015

Small

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Resistively switching devices are considered promising for next-generation nonvolatile random-access memories. Today, such memories are fabricated by means of "top-down approaches" applying thin films sandwiched between nanoscaled electrodes. In contrast, this work presents a "bottom-up approach" disclosing for the first time the resistive switching (RS) of individual TiO2 nanoparticles (NPs). The NPs, which have sizes of 80 and 350 nm, respectively, are obtained by wet chemical synthesis and thermally treated under oxidizing or vacuum conditions for crystallization, respectively. These NPs are deposited on a Pt/Ir bottom electrode and individual NPs are electrically characterized by means of a nanomanipulator system in situ, in a scanning electron microscope. While amorphous NPs and calcined NPs reveal no switching hysteresis, a very interesting behavior is found for the vacuum-annealed, crystalline TiO(2-x) NPs. These NPs reveal forming-free RS behavior, dominantly complementary switching (CS) and, to a small degree, bipolar switching (BS) characteristics. In contrast, similarly vacuum-annealed TiO2 thin films grown by atomic layer deposition show standard BS behavior under the same conditions. The interesting CS behavior of the TiO(2-x) NPs is attributed to the formation of a core-shell-like structure by re-oxidation of the reduced NPs as a unique feature.

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Section: Resultsmentioning

confidence: 99%

Resistive Switching of Individual, Chemically Synthesized TiO₂Nanoparticles

Schmidt

Hoffmann‐Eifert

Zhang

et al. 2015

Small

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“…The bipolar resistive switching of NiO had been interpreted as a result of oxygen-vacancymigration induced stoichiometry change, [14][15][16] resembling the oxygen-vacancy-based model of VCM in the n-type oxides. 2,[17][18][19] However, the charge carrier type may has a decisive impact on the switching mechanism, as observed in the case of unipolar resistive switching of TiO 2 and NiO.…”

Section: Introductionmentioning

confidence: 99%

Deterministic Role of Concentration Surplus of Cation Vacancy over Anion Vacancy in Bipolar Memristive NiO

Sun

Zhao

et al. 2016

ACS Appl. Mater. Interfaces

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Migration of oxygen vacancies has been proposed to play an important role in the bipolar memristive behaviors because oxygen vacancies can directly determine the local conductivity in many systems. However, a recent theoretical work demonstrated that both migration of oxygen vacancies and coexistence of cation and anion vacancies are crucial to the occurrence of bipolar memristive switching, normally observed in the small-sized NiO. So far, experimental work addressing this issue is still lacking. In this work, with conductive atomic force microscopy and combined scanning transmission electron microscopy and electron energy loss spectroscopy, we reveal that concentration surplus of Ni vacancy over O vacancy determines the bipolar memristive switching of NiO films. Our work supports the dual-defects-based model, which is of fundamental importance for understanding the memristor mechanisms beyond the well-established oxygen-vacancy-based model. Moreover, this work provides a methodology to investigate the effect of dual defects on memristive behaviors.

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“…set or reset) voltage value was obtained in the case of the C-AFM measurements. Although this latter observation needs further clarification, one can invoke the electric field enhancement effect produced in the vicinity of the AFM tip [27] which may improve the migration of metallic ions during set or reset process. In addition, since set and reset processes are electrode-dominated in the case of conductive-bridge devices [5], the difference in set/reset voltages may also originates from the different electronic properties, such as work function of the electrode material, where the ~800 mV difference observed between set voltages almost corresponds to the work function difference between W (4.55 eV) [28] and platinum-iridium (5.3 eV).…”

Section: A Step Toward Crossbar Memory Array On Flexible Substratementioning

confidence: 99%

Ge2Sb2Te5 layer used as solid electrolyte in conductive-bridge memory devices fabricated on flexible substrate

Deleruyelle

Putero

Ouled-Khachroum

et al. 2013

Solid-State Electronics

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This paper shows that the well-know chalcogenide Ge 2 Sb 2 Te 5 (GST) in its amorphous state may be advantageously used as solid electrolyte material to fabricate Conductive-Bridge Random Access Memory (CBRAM) devices. GST layer was sputtered on preliminary inkjet-printed silver lines acting as active electrode on either silicon or plastic substrates. Whatever the substrate, the resistance switching is unambiguously attested at a nanoscale by means of conductive-atomic force microscopy (C-AFM) using a Pt-Ir coated tip on the GST surface acting as a passive electrode. The resistance change is correlated to the appearance or disappearance of concomitant hillocks and current spots at the surface of the GST layer. This feature is attributed to the formation/dissolution of a silver-rich protrusion beneath the AFM tip during set/reset operation. Beside, this paper constitutes a step toward the elaboration of crossbar memory arrays on flexible substrates since CBRAM operations were demonstrated on W/GST/Ag crossbar memory cells obtained from an heterogeneous fabrication process combining physical deposition and inkjet-printing.

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Surface redox induced bipolar switching of transition metal oxide films examined by scanning probe microscopy

Cited by 24 publications

References 10 publications

Resistive Switching of Individual, Chemically Synthesized TiO₂Nanoparticles

Resistive Switching of Individual, Chemically Synthesized TiO₂Nanoparticles

Deterministic Role of Concentration Surplus of Cation Vacancy over Anion Vacancy in Bipolar Memristive NiO

Ge2Sb2Te5 layer used as solid electrolyte in conductive-bridge memory devices fabricated on flexible substrate

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Surface redox induced bipolar switching of transition metal oxide films examined by scanning probe microscopy

Cited by 24 publications

References 10 publications

Resistive Switching of Individual, Chemically Synthesized TiO2Nanoparticles

Resistive Switching of Individual, Chemically Synthesized TiO2Nanoparticles

Deterministic Role of Concentration Surplus of Cation Vacancy over Anion Vacancy in Bipolar Memristive NiO

Ge2Sb2Te5 layer used as solid electrolyte in conductive-bridge memory devices fabricated on flexible substrate

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Resistive Switching of Individual, Chemically Synthesized TiO₂Nanoparticles

Resistive Switching of Individual, Chemically Synthesized TiO₂Nanoparticles