Electrode-dependent electrical properties of metal/Nb-doped SrTiO3 junctions

Park, C.; Seo, Yasuhisa; Jung, Jae-Hun; Kim, Dong Wook

doi:10.1063/1.2872707

Cited by 110 publications

(85 citation statements)

References 21 publications

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“…A similar switching behavior has been reported in metal/Nb-doped SrTiO 3 single crystal structures without active layer. [23][24][25] Figure 3a is a schematic drawing of switching polarities as functions of Sr 2 TiO 4 layer thickness and growth temperature. Figure 3b corresponds to Figure1b which shows I-V curves of the junction with a 10 nm thick Sr 2 TiO 4 layer where both switching polarities were observed.…”

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confidence: 99%

Impact of Defect Distribution on Resistive Switching Characteristics of Sr₂TiO₄ Thin Films

et al. 2010

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The resistive switching properties of Sr2TiO4 thin films with specific defect distribution have been studied. Junctions of Sr2TiO4 thin films containing a high density of defects show well‐pronounced resistive switching properties while those with well‐ordered microstructure exhibited insignificant hysteresis windows. This work clearly demonstrates the crucial role of defects for the microscopic switching mechanisms in oxide thin films.

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confidence: 99%

Impact of Defect Distribution on Resistive Switching Characteristics of Sr₂TiO₄ Thin Films

et al. 2010

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“…Thus, the electronic barrier at these metal/oxide interfaces is not dominated by the work function of the electrode metals, which can be explained by the presence of a high concentration of interface states that are intrinsic to the oxide surfaces or are caused by the metal deposition [29,30]. Interface chemical reactions [31,32] between the metal electrodes and the Ti oxide can be a major source of these interface states.…”

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confidence: 99%

Metal/TiO2 interfaces for memristive switches

et al. 2011

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The interfaces between metal electrodes and the oxide in TiO 2 -based memristive switches play a key role in the switching as well as in the I -V characteristics of the devices in different resistance states. We demonstrate here that the work function of the metal electrode has a surprisingly minor effect in determining the electronic barrier at the interface. In contrast, Ti oxides can be readily reduced by most electrode metals. The amount of oxygen vacancies created by these chemical reactions essentially determines the electronic barrier at the device interfaces.The memristor, the fourth fundamental passive circuit element [1][2][3], has a wide variety of potential applications based on its promising device properties [1][2][3][4][5][6][7], including non-volatility, fast switching (<10 ns), low energy (∼1 pJ/operation), multiple-state operation, scalability and stackability. As suggested by the name, memristors can be used for information storage [8][9][10][11][12][13][14]. Moreover, memristors can function as stateful Boolean logic gates via the material implication operation [15]. In addition, memristors can also be used for neuromorphic computing [16,17] because of their analog switching, and some hybrid circuits due to their ease of stacking [18,19].Among all the kinds of switching materials that have been reported, oxides are the most extensively studied [4]. The interfaces between the metal electrodes and the oxide play a crucial role, especially for bipolar switches [5,6,20]. Under an applied electric field, oxygen vacancies can drift into the interface region, reducing the electronic barrier and resulting in a low-resistance state. Under an electric field with the opposite polarity, the oxygen vacancies are repelled away from the interface region, recovering the electronic barrier to regain the high resistance state [6,21,22]. A family of nanodevices with different switching and currentvoltage (I -V ) characteristics has been demonstrated by manipulating the elemental composition at the two interfaces of a simple metal/oxide/metal device stack [23]. For a crossbar array of memristors in a storage/memory circuit, sneak path currents [24] can be minimized by using memristors with a rectifying I -V characteristic, especially when they are in the low-resistance state. Therefore, interface engineering is critical to obtain the desired switching behavior and electrical properties for memristive devices.From a semiconductor physics point of view, the work function of the electrode metal might be an important factor in determining the electronic barrier at the metal/oxide interface [25]. This barrier in our thin film devices is not a traditional Schottky barrier because the oxide film is amorphous with a large concentration of defects and likely thinner than the depletion region of the semiconducting oxide. We prepared a set of 5 µm × 5 µm cross-point devices with six different top electrode metals (Au, Pt, Ag, Ni, W and Ti) to examine the effect of these contacts on the I -V characteristics, as show...

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“…In general, understanding the switching mechanisms is a major challenge in achieving better non-volatile memory performance. To explain the bipolar RS phenomenon, various electric field polarity-dependent models, including ion migration 19 , Mott transition 30 and formation of Schottky barrier [31][32][33] , have been suggested. In particular, the Schottky barrier formed at the interface has been identified to trigger the RS behaviour for Nb:STO-based junctions 31,33 .…”

Section: Resultsmentioning

confidence: 99%

“…To explain the bipolar RS phenomenon, various electric field polarity-dependent models, including ion migration 19 , Mott transition 30 and formation of Schottky barrier [31][32][33] , have been suggested. In particular, the Schottky barrier formed at the interface has been identified to trigger the RS behaviour for Nb:STO-based junctions 31,33 . More specifically, changes in the Schottky barrier by either a charge trap at the defect states or oxygen migration due to applied bias voltage has been frequently attributed for the bipolar RS behaviour 31,32,34 .…”

Section: Resultsmentioning

confidence: 99%

Resonant tunnelling in a quantum oxide superlattice

et al. 2015

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Resonant tunnelling is a quantum mechanical process that has long been attracting both scientific and technological attention owing to its intriguing underlying physics and unique applications for high-speed electronics. The materials system exhibiting resonant tunnelling, however, has been largely limited to the conventional semiconductors, partially due to their excellent crystalline quality. Here we show that a deliberately designed transition metal oxide superlattice exhibits a resonant tunnelling behaviour with a clear negative differential resistance. The tunnelling occurred through an atomically thin, lanthanum d-doped SrTiO 3 layer, and the negative differential resistance was realized on top of the bipolar resistance switching typically observed for perovskite oxide junctions. This combined process resulted in an extremely large resistance ratio (B10 5 ) between the high and low-resistance states. The unprecedentedly large control found in atomically thin d-doped oxide superlattices can open a door to novel oxide-based high-frequency logic devices.

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Electrode-dependent electrical properties of metal/Nb-doped SrTiO3 junctions

Cited by 110 publications

References 21 publications

Impact of Defect Distribution on Resistive Switching Characteristics of Sr₂TiO₄ Thin Films

Impact of Defect Distribution on Resistive Switching Characteristics of Sr₂TiO₄ Thin Films

Metal/TiO2 interfaces for memristive switches

Resonant tunnelling in a quantum oxide superlattice

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Electrode-dependent electrical properties of metal/Nb-doped SrTiO3 junctions

Cited by 110 publications

References 21 publications

Impact of Defect Distribution on Resistive Switching Characteristics of Sr2TiO4 Thin Films

Impact of Defect Distribution on Resistive Switching Characteristics of Sr2TiO4 Thin Films

Metal/TiO2 interfaces for memristive switches

Resonant tunnelling in a quantum oxide superlattice

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Impact of Defect Distribution on Resistive Switching Characteristics of Sr₂TiO₄ Thin Films

Impact of Defect Distribution on Resistive Switching Characteristics of Sr₂TiO₄ Thin Films