Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Atomic switches: Ionic computing

Figure 1: Comparison between semiconductor-transistor-based and atomic-switch-based
switching circuits.
Figure 1: Comparison between semiconductor-transistor-based and atomic-switch-based switching circuits.

Abstract:
A critical review of the current status and future prospects of new computing architectures based on ‘atomic switches' fabricated by controlling the movement of cationic ions during solid electrochemical reactions.

Atomic switches: Ionic computing

Japan | Posted on March 24th, 2011

A review of new types of nanodevices and computing based on cationic-based atomic switches is presented Takami Hino and coworkers at the WPI Center for Materials Nanoarchitectonics at the National Institute for Materials Science (NIMS) in Tsukuba, Japan. The review paper is published this month in the journal Science and Technology of Advanced Materials.

The researchers describe the fundamental mechanisms governing the operation of nanoionic atomic switches with detailed examples of their own three terminal devices, and predict a bright future for integrating atomic switches with conventional silicon devices by using ionic conductive materials.

Mechanical atomic switches—operated by manipulating atoms between a conducting surface and the tip of a scanning tunneling microscope (STM)—were first reported in the early 1990s. These mechanical switches triggered intense interest in the development of electrically controlled atomic switches, produced by the movement of cationic ions in solid electrochemical reactions, where the operation of cationic atomic switches is governed by the formation of a conducting channel either in or on an ionic conductor.

Now, the challenge for researchers in this field is the fabrication of nanoionic device structures that can be integrated with conventional metal oxide silicon semiconductor devices.

In its simplest configuration, the operation of a nanoionic atomic switch consists of the formation and disintegration of nanometer sized metallic wires via a solid electrochemical reaction, which leads to major changes in the resistance between electrodes—the ‘on' and ‘off' states.

In this review, Hino and colleagues describe the control of silver ions in silver sulphide—an ionic conductor— using an STM tip to inject electrons to produce silver protrusions on the surface of silver sulphide, and their shrinkage by applying an appropriate bias voltage between the STM tip and electrode. Importantly, the application of a positive bias between a silver sulphide tip and a platinum surface leads to the growth of silver wires and a negative bias led their shrinkage. This bipolar control is important for practical device applications.

Gap-type atomic switches are a fundamental building block for bipolar nanoionic devices. Here, the researchers give a detailed account of bipolar switching using silver sulphide STM tips and platinum electrodes based on their own experiments on ‘crossbar' device structures with a 1 nm gap between silver sulphide and platinum, with emphasis on the physical mechanism governing high speed switching at 1 MHz, and the finding that switching time decreases exponentially with increasing bias voltage. The authors stress that the development of a reproducible method for fabricating ‘crossbar' devices was a major breakthrough, which enabled the first demonstration of nanoionic circuits such as logic gates.

With a view to practical applications of atomic switches, the authors give examples of advanced atomic switches including gapless-type devices consisting of metal/ionic conductor/metal structures, where one of the metals is electrochemically active and the other inert. Notably, recent reports on the use of metal oxides as ionic conductors have added further momentum for device commercialization.

Notably, gapless atomic switches also act as so-called ‘memristors' (memory resistors)—passive two terminal multi-state memory devices—where the size of the nanowire protrusion governs the operation characteristics.

Other advanced atomic switches include: three terminal devices such as structures with a solid copper sulphide electrolyte, where the formation of a copper bridge between a platinum-source electrode and copper-drain electrode is controlled by a copper gate-electrode; and photoassisted atomic switches, which do not require nanogaps, and nanowire protrusions are grown by optical irradiation of a photoconductive material located between the anion and electron conducting electrode and a counter metal electrode. Intriguingly, since the switch is turned ‘on' when the growing metal protrusion reaches the counter electrode, and the protrusion does not grow in the dark, the photoassisted atomic switch behaves as a programmable switch that could be used in erasable programmable read-only memory (EPROM).

The authors also describe the ‘learning abilities' of atomic switches capable of short-term and long-term memories in single nanoionic devices; nonvolatile bipolar switches; two terminal atomic switch logic gates; and field programmable gate arrays integrated with CMOS devices.

This review contains 77 references and 20 figures and provides an invaluable source of up-to-date information for newcomers and experts in this exciting area of research.

####

Contacts:
National Institute for Materials Science
Tsukuba, Japan
Email:
Tel. +81-(0)29-859-2494

Copyright © National Institute for Materials Science

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

[1] Takami Hino et al, Atomic switches: atomic-movement-controlled nanodevices for new types of computing, Sci. Technol. Adv. Mater.12 (2011) 013003.

[2] National Institute for Materials Science:

[3] The International Center for Materials Nanoarchitectonics (MANA)

Related News Press

News and information

The International Space Elevator Consortium (ISEC) is proud to announce the 2014 Space Elevator Conference! This annual event will be held at the Museum of Flight in Seattle, Washington from Friday, August 22nd through Sunday, August 24th August 19th, 2014

KaSAM-2014 International Conference (September 7-10, 2014, Kathmandu, Nepal) August 19th, 2014

Success in Intracellular Imaging of Cesium Distribution in Plants Used for Cesium Absorption August 19th, 2014

Electrical engineers take major step toward photonic circuits: Team invents non-metallic metamaterial that enables them to 'compress' and contain light August 19th, 2014

Graphene rubber bands could stretch limits of current healthcare, new research finds August 19th, 2014

Imaging

Success in Intracellular Imaging of Cesium Distribution in Plants Used for Cesium Absorption August 19th, 2014

Oxford Instruments Asylum Research Receives the 2014 Microscopy Today Innovation Award for blueDrive Photothermal Excitation August 18th, 2014

Molecular Machines

Optimum inertial design for self-propulsion: A new study investigates the effects of small but finite inertia on the propulsion of micro and nano-scale swimming machines July 29th, 2014

Breakthrough laser experiment reveals liquid-like motion of atoms in an ultra-cold cluster: University of Leicester research team unlocks insights into creation of new nano-materials July 25th, 2014

NIST shows ultrasonically propelled nanorods spin dizzyingly fast July 22nd, 2014

University of Illinois researchers demonstrate novel, tunable nanoantennas July 14th, 2014

Chip Technology

Electrical engineers take major step toward photonic circuits: Team invents non-metallic metamaterial that enables them to 'compress' and contain light August 19th, 2014

Promising Ferroelectric Materials Suffer From Unexpected Electric Polarizations: Brookhaven Lab scientists find surprising locked charge polarizations that impede performance in next-gen materials that could otherwise revolutionize data-driven devices August 18th, 2014

AI Technology (AIT) Introduces Novel High Temperature Large Area Underfill with Proven Stress Absorption August 15th, 2014

Iranian Scientists Stabilize Protein on Highly Stable Electrode Surface August 14th, 2014

Nanoelectronics

A*STAR and industry form S$200M semiconductor R&D July 25th, 2014

A Crystal Wedding in the Nanocosmos July 23rd, 2014

3-D nanostructure could benefit nanoelectronics, gas storage: Rice U. researchers predict functional advantages of 3-D boron nitride July 15th, 2014

IBM Announces $3 Billion Research Initiative to Tackle Chip Grand Challenges for Cloud and Big Data Systems: Scientists and engineers to push limits of silicon technology to 7 nanometers and below and create post-silicon future July 10th, 2014

Announcements

Сalculations with Nanoscale Smart Particles August 19th, 2014

Life on Mars? Implications of a newly discovered mineral-rich structure August 19th, 2014

Harris & Harris Group Letter to Shareholders on Website August 19th, 2014

Electrical engineers take major step toward photonic circuits: Team invents non-metallic metamaterial that enables them to 'compress' and contain light August 19th, 2014

Tools

Oxford Instruments Asylum Research Receives the 2014 Microscopy Today Innovation Award for blueDrive Photothermal Excitation August 18th, 2014

Laser makes microscopes way cooler: Cooling a nanowire probe with a laser could lead to substantial improvements in the sensitivity of atomic force probe microscopes August 15th, 2014

JPK reports on the use of AFM and advanced fluorescence microscopy at the University of Freiburg August 13th, 2014

Phasefocus reports on the use of their high-precision Lens Profiler for measuring contact lens thickness at the Brien Holden Vision Institute in Sydney, Australia August 13th, 2014

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE