Simulation of charge transport in multi-island tunneling devices: Application to disordered one-dimensional systems at low and high biases

Savaikar, Madhusudan A.; Banyai, Douglas; Bergstrom, Paul L.; Jaszczak, John A.

doi:10.1063/1.4821224

Cited by 10 publications

(36 citation statements)

References 33 publications

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“…We have examined at T = 0 K the up-steps for the disordered 25-junction chain system previously studied by Savaikar et al, 16 which has reasonably strong inter-island couplings, and for which the interisland spacings vary over a range from ∼1.1 nm to ∼4.9 nm and island radii vary from ∼4.2 nm to ∼9.6 nm. The model device is schematically shown in Fig.…”

Section: Physical Mechanism Leading To the Coulomb Blockade And Thresmentioning

confidence: 99%

“…In a disordered system with a sufficiently random distribution in junction widths and island radii, the junction charging energies are expected to have a fairly broad distribution. 16 The junction charging energy (E c ) is the energy required for a single electron transition across a junction between the two coupled islands, as determined by all of the capacitances of the system. 16 In a system with reasonably strong inter-island capacitive couplings, E c is influenced by both the junction widths and the island radii, but predominantly by the later.…”

Section: Physical Mechanism Leading To the Coulomb Blockade And Thresmentioning

confidence: 99%

“…16 The junction charging energy (E c ) is the energy required for a single electron transition across a junction between the two coupled islands, as determined by all of the capacitances of the system. 16 In a system with reasonably strong inter-island capacitive couplings, E c is influenced by both the junction widths and the island radii, but predominantly by the later. These charging energies, along with the evolving charge states of the system play a crucial role in determining the V th and the IV characteristics.…”

Section: Physical Mechanism Leading To the Coulomb Blockade And Thresmentioning

confidence: 99%

“…4,6,13 Middleton and Wingreen 14 carried out a theoretical investigation on an array of islands with uniform capacitances but with the potential levels randomly offset by quenched background charges showing the linear variation of device V th (N). The computational study by Elteto et al 15 extended the work to a uniform system with the nearestneighbor inter-island coupling in order to explain the experimental device features observed by Parthasarathy et al 6 In studies carried out on a disordered system with strong inter-island capacitive coupling and non-zero screening length (λ) that defines the sphere of electrostatic influence of the charge carrier, Lee et al 4 and Savaikar et al 16 showed that V th (N) is still linear, but it is difficult to analytically predict the slope of the V th dependence on N. In spite of numerous efforts, no definitive work has been done to demonstrate the mechanisms that give rise to CB and CS structure that extend from small to large source-drain biases especially in devices consisting of stronglycoupled islands. In this computational study of one-dimensional (1D) chains of gold nano-islands based on semi-classical tunneling theory and kinetic Monte Carlo (MC) simulation, we describe the physical mechanism behind the CB and CS structures at temperature T = 0 K at * Electrochemical Society Member.…”

mentioning

confidence: 99%

“…These charging energies, along with the evolving charge states of the system play a crucial role in determining the V th and the IV characteristics. 16 In any static charge state of the system, the change in free energy ( W i j = −eV i j + E c,i j , where V ij is the potential drop across the junction coupling the two islands i and j, and E c,ij is its charging energy) of the system for tunneling between any two islands i and j has W i j > 0 and the tunneling is forbidden for T = 0 K. 16 For any transition to take place at T = 0 K, W i j needs to be less than or equal to zero, and the energy required to overcome the coulomb energy barrier can be supplied only by the external sources. When a 1D system consisting of nano-islands with strong inter-islandand self-capacitances (and with no background charges) is biased by ) unless CC License in place (see abstract).…”

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confidence: 99%

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Physical Mechanisms Leading to the Coulomb Blockade and Coulomb Staircase Structures in Strongly Coupled Multi-Island Single-Electron Devices

Savaikar

Bergstrom

Jaszczak

2016

ECS J. Solid State Sci. Technol.

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Controlled transport of electrons through tunnel junctions and their confinement by mesoscopic structures have opened up immense possibilities of single-electron device (SED) applications. The realization of a practical working SED has remained challenging largely owing to the poor understanding of the physics of operation of singe-electron tunneling devices, especially of those with multiple nanometer-sized islands. In this simulation study of one-dimensional (1D) multi-island chains, we propose physical mechanisms that lead to the coulomb blockade (CB) and coulomb staircase (CS) characteristics that are enhanced by the geometrical disorder in the chain. With increasing source-drain (V DS = V D − V S ) bias, a multi-island device has to overcome multiple discrete energy barriers (up-steps) for charge advancement before reaching the threshold voltage (V th ). Beyond V th , current flow is rate-limited by certain junctions with low transition rates, which leads to the CS structures in the current-voltage (IV) characteristic. Each step in the CS is characterized by a unique distribution of charges on the islands, each with an associated distribution of tunneling probabilities that depend on both the charge state and V DS . This study marks an important step in unraveling the microscopic details of SED operation and will inspire further experimental and theoretical studies. Two particularly interesting and important features of a singleelectron device (SED) are the coulomb blockade (CB) and coulomb staircase (CS) current-voltage (IV) characteristics that are manifestations of the charging effects of the islands due to their small size when they are at the nanometer scale. While many research groups 1-7 have fabricated SEDs, some demonstrating the CB and the CS features even at room temperature, 7 a few others have successfully explored the applications of a single-electron transistor (SET) device for nanometerscale displacement sensing, 8 thermometry, 9 and the SET as a fast and ultrasensitive electrometer.10,11 Single-electron behavior in materials such as single-wall carbon nanotubes has also been demonstrated. 12But to successfully design and fabricate a SED that can exhibit the CB and CS features, it is necessary to better understand the physics behind the charge transport leading to the CB and CS features in the device IV characteristics, which has remained poorly understood so far. A nearly linear variation of the device threshold voltage (V th ) with the number of islands along the chain (N), which is proportional to the chain length (L), has been observed in the experimental devices. 4,6,13 Middleton and Wingreen 14 carried out a theoretical investigation on an array of islands with uniform capacitances but with the potential levels randomly offset by quenched background charges showing the linear variation of device V th (N). The computational study by Elteto et al. 15 extended the work to a uniform system with the nearestneighbor inter-island coupling in order to explain the experimental device features o...

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Section: Physical Mechanism Leading To the Coulomb Blockade And Thresmentioning

confidence: 99%

Section: Physical Mechanism Leading To the Coulomb Blockade And Thresmentioning

confidence: 99%

Section: Physical Mechanism Leading To the Coulomb Blockade And Thresmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Physical Mechanisms Leading to the Coulomb Blockade and Coulomb Staircase Structures in Strongly Coupled Multi-Island Single-Electron Devices

Savaikar

Bergstrom

Jaszczak

2016

ECS J. Solid State Sci. Technol.

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Direct Observation of Conversion Between Threshold Switching and Memory Switching Induced by Conductive Filament Morphology

Sun

Liu

et al. 2014

Adv Funct Materials

290

221

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Although the kinetics of CF formation/ dissolution is still unclear, it is widely accepted that the CF formation/dissolution is strongly related to the electromigration and electrochemical reaction of anion (i.e., oxygen vacancy) [13][14][15][16] or cation (i.e., Cu 2+ , Ag + or Ni 2+ ). [17][18][19][20][21][22] Generally, RS behavior can be classifi ed as two modes: nonvolatile memory switching (MS) and volatile threshold switching (TS). In the MS mode, both LRS and HRS can be maintained after removing the external voltage, while the LRS in the TS mode will be back to the HRS once the applied voltage is smaller than a critical value. [23][24][25] To avoid confusion with MS, the LRS and HRS in TS are renamed as "TS ON-state" and "TS OFFstate" in this article. The MS device can be used for the non-volatile data storage [1][2][3][4][5] while TS device can be as a selector in series with memory cell to suppress crosstalk effect in the crossbar array. [26][27][28][29][30] Recently, some groups reported that TS and MS can coexist and mutually transform in a single device at suitable external excitation. [23][24][25][26][27][28] Several models have been proposed to explain this phenomenon, including CF thermal instability, [ 23 ] strong electron correlation effect, [ 24 ] quantum-wire model, [ 25 ] interface barrier modulation, [ 26 ] and space charge effect. [ 27 ] However, the underlying mechanism of the phenomenon is still unclear, especially lacking of direct evidences to uncover when and how the two RS modes happen and what is the internal relationship between them.Here, we demonstrate that the TS and MS modes can be modulated in the Ag/SiO 2 /Pt structure by controlling the compliance current ( I CC ) in electroforming. We systematically investigate the morphologies, chemical components, and dynamic growth of the CF using scanning electron microscope (SEM), high-resolution transmission electron microscopy (HRTEM) and electron energy loss spectroscopy (EELS) analysis. The results confi rm that the TS and MS modes correspond to the CF consisting of isolated and continuous Ag nanocrystals, respectively. In addition, by Kelvin probe force microscopy (KPFM) studies, the voltage potential distribution of CF in the ON-and OFF-state further indicate that the TS mode is Volatile threshold switching (TS) and non-volatile memory switching (MS) are two typical resistive switching (RS) phenomena in oxides, which could form the basis for memory, analog circuits, and neuromorphic applications. Interestingly, TS and MS can be coexistent and converted in a single device under the suitable external excitation. However, the origin of the transition from TS to MS is still unclear due to the lack of direct experimental evidence. Here, conversion between TS and MS induced by conductive fi lament (CF) morphology in Ag/SiO 2 /Pt device is directly observed using scanning electron microscopy and high-resolution transmission electron microscopy. The MS mechanism is related to the formation and dissolution of CF consisting of continuous Ag...

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Engineering Silver Nanowire Networks: From Transparent Electrodes to Resistive Switching Devices

Wan

Qü

et al. 2017

ACS Appl. Mater. Interfaces

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Metal nanowires (NWs) networks with high conductance have shown potential applications in modern electronic components, especially the transparent electrodes over the past decade. In metal NW networks, the electrical connectivity of nanoscale NW junction can be modulated for various applications. In this work, silver nanowire (Ag NW) networks were selected to achieve the desired functions. The Ag NWs were first synthesized by a classic polyol process, and spin-coated on glass to fabricate transparent electrodes. The as-fabricated electrode showed a sheet resistance of 7.158 Ω □ with an optical transmittance of 79.19% at 550 nm, indicating a comparable figure of merit (FOM, or Φ) (13.55 × 10 Ω). Then, two different post-treatments were designed to tune the Ag NWs for not only transparent electrode but also for threshold resistive switching (RS) application. On the one hand, the Ag NW film was mechanically pressed to significantly improve the conductance by reducing the junction resistance. On the other hand, an Ag@AgO core-shell structure was deliberately designed by partial oxidation of Ag NWs through simple ultraviolet (UV)-ozone treatment. The Ag core can act as metallic interconnect and the insulating AgO shell acts as a switching medium to provide a conductive pathway for Ag filament migration. By fabricating Ag/Ag@AgO/Ag planar structure, a volatile threshold switching characteristic was observed and an on/off ratio of ∼100 was achieved. This work showed that through different post-treatments, Ag NW network can be engineered for diverse functions, transforming from transparent electrodes to RS devices.

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Simulation of charge transport in multi-island tunneling devices: Application to disordered one-dimensional systems at low and high biases

Abstract: Articles you may be interested in Multi-island single-electron devices from self-assembled colloidal nanocrystal chains Appl.

Cited by 10 publications

References 33 publications

Physical Mechanisms Leading to the Coulomb Blockade and Coulomb Staircase Structures in Strongly Coupled Multi-Island Single-Electron Devices

Physical Mechanisms Leading to the Coulomb Blockade and Coulomb Staircase Structures in Strongly Coupled Multi-Island Single-Electron Devices

Direct Observation of Conversion Between Threshold Switching and Memory Switching Induced by Conductive Filament Morphology

Engineering Silver Nanowire Networks: From Transparent Electrodes to Resistive Switching Devices

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