Non-volatile memory device using a polymer modified nanocrystal (original) (raw)
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Planar non-volatile memory based on metal nanoparticles
Materials Research Society Symposium Proceedings, 2011
Resistive switching properties of silver nanoparticles hosted in an insulating polymer matrix (poly(N-vinyl-2-pyrrolidone) are reported. Planar devices structures using interdigitated gold electrodes were fabricated. These devices have on/off resistance ratio as high as 10 3 , retention times reaching to months and good endurance cycles. Temperature-dependent measurements show that the charge transport is weakly thermal activated (73 meV) for both states suggesting that nanoparticles will not aggregate into a metallic filament.
Journal of Alloys and Compounds, 2018
Multilevel conductance switching was achieved using silver nanoparticles (Ag NPs) embedded in poly(9vinylcarbazole) (PVK) with a structure of ITO/PVK:Ag NPs/Al. The current-voltage (I-V) curves of the memory devices at low reading voltages showed three distinguished states of current. The memory devices exhibited non-volatile rewritable memory characteristics. The carrier transport mechanisms of the devices in each state were analyzed by theoretical models based on the experimental I-V data. In addition, retention time measurements showed clearly three current states with good data retention properties. From the retention times test, the average values of ON/OFF, ON/intermediate (INTERM) and INTERM/OFF current ratios of the memory devices were 1.7 Â 10 6 , 3.5 Â 10 2 and 5.0 Â 10 3 , respectively.
Resistive Random Access Memories (RRAMs) Based on Metal Nanoparticles
2011
It is demonstrated that planar structures based on silver nanoparticles hosted in a polymer matrix show reliable and reproducible switching properties attractive for non-volatile memory applications. These systems can be programmed between a low conductance (off-state) and high conductance (on-state) with an on/off ratio of 3 orders of magnitude, large retention times and good cycle endurance. The planar structure design offers a series of advantages discussed in this contribution, which make it an ideal tool to elucidate the resistive switching phenomena.
Nonvolatile Memory Elements Based on Organic Materials
Many organic electronic devices exhibit switching behavior, and have therefore been proposed as the basis for a nonvolatile memory (NVM) technology. This Review summarizes the materials that have been used in switching devices, and describes the variety of device behavior observed in their charge–voltage (capacitive) or current–voltage (resistive) response. A critical summary of the proposed charge-transport mechanisms for resistive switching is given, focusing particularly on the role of filamentary conduction and of deliberately introduced or accidental nanoparticles. The reported device parameters (on–off ratio, on-state current, switching time, retention time, cycling endurance, and rectification) are compared with those that would be necessary for a viable memory technology.
A New Nonvolatile Bistable Polymer-Nanoparticle Memory Device
IEEE Electron Device Letters, 2007
In this letter, we demonstrate a new organic bistable nonvolatile memory device that is adopting polymer-chainstabilized gold (Au) nanoparticles in a host polymer as a memory active layer. In this letter, the Au nanoparticles are well dispersed in the host polymer so as to enhance stability of memory devices. Current-voltage characteristics show that the device switches from an initial low-conductivity state to a high-conductivity state upon applying an external electric field at room temperature. This memory can be switched ON and OFF for over 150 times without an apparent performance degradation. In addition, the memory state can retain for over 36 000 s in air. This memory device is thus considered to be a suitable candidate for flexible electronics applications.
Nanotechnology, 2009
The resistive switching characteristics of polyfluorene-derivative polymer material in a sub-micron scale via-hole device structure were investigated. The scalable via-hole sub-microstructure was fabricated using an e-beam lithographic technique. The polymer non-volatile memory devices varied in size from 40 × 40 μm 2 to 200 × 200 nm 2 . From the scaling of junction size, the memory mechanism can be attributed to the space-charge-limited current with filamentary conduction. Sub-micron scale polymer memory devices showed excellent resistive switching behaviours such as a large ON/OFF ratio (I ON /I OFF ∼ 10 4 ), excellent device-to-device switching uniformity, good sweep endurance, and good retention times (more than 10 000 s). The successful operation of sub-micron scale memory devices of our polyfluorene-derivative polymer shows promise to fabricate high-density polymer memory devices.
Nonvolatile resistive switching memories-characteristics, mechanisms and challenges
Progress in Natural Science: Materials International, 2010
This review presents a summary of current understanding of the resistive switching materials and devices which have inspired extraordinary interest all over the world. Although various switching behaviors and different conductive mechanisms are involved in the field, the resistive switching effects can be roughly classified into filament type and interface type according to their conducting behavior in low resistance state. For those filament based systems, the migration of metallic cations and oxygen vacancies, characterization of the filament as well as the role of Joule heating effects are discussed in detail. As to the interface based system, we describe the methods of modulating interface barrier height such as using different electrodes, inserting a tunnel layer. It is demonstrated that the switching mechanism can transform from one to another along the change of some specific conditions. We also give an overview on the latest developments in multilevel storage and the resistive switching in organic materials. In this paper, the solutions to address the sneak current problems in crossbar structure are discussed.
Admittance spectroscopy of polymer-nanoparticle nonvolatile memory devices
Applied Physics Letters, 2006
Nonvolatile resistive memory consisting of gold nanoparticles embedded in the conducting polymer poly͑4-n-hexylphenyldiphenylamine͒ examined using admittance spectroscopy. The frequency dependence of the devices indicates space-charge-limited transport in the high-conductivity "on" state, as well as evidence for similar transport in the lower-conductivity "off" state. Furthermore, the larger dc capacitance of the on state indicates that a greater amount of filling of the midgap nanoparticle trap levels increases the overall device conductivity, leading to the memory effect.
Multistate resistive switching in silver nanoparticle films
Science and Technology of Advanced Materials
Resistive switching devices have garnered significant consideration for their potential use in nanoelectronics and non-volatile memory applications. Here we investigate the nonlinear current–voltage behavior and resistive switching properties of composite nanoparticle films comprising a large collective of metal–insulator–metal junctions. Silver nanoparticles prepared via the polyol process and coated with an insulating polymer layer of tetraethylene glycol were deposited onto silicon oxide substrates. Activation required a forming step achieved through application of a bias voltage. Once activated, the nanoparticle films exhibited controllable resistive switching between multiple discrete low resistance states that depended on operational parameters including the applied bias voltage, temperature and sweep frequency. The films’ resistance switching behavior is shown here to be the result of nanofilament formation due to formative electromigration effects. Because of their tunable a...