Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


DHgate

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

Solid state physics: Quantum matter stuck in unrest August 1st, 2015

Self-assembling, biomimetic membranes may aid water filtration August 1st, 2015

Transparent, electrically conductive network of encapsulated silver nanowires: A novel electrode for optoelectronics August 1st, 2015

Kalam: versatility personified August 1st, 2015

Imaging

Take a trip through the brain July 30th, 2015

Publication on Atomic Force Microscopy based nanoscale IR Spectroscopy (AFM-IR) persists as a 2015 top downloaded paper July 29th, 2015

Short wavelength plasmons observed in nanotubes: Berkeley Lab researchers create Ludinger liquid plasmons in metallic SWNTs July 28th, 2015

Reshaping the solar spectrum to turn light to electricity: UC Riverside researchers find a way to use the infrared region of the sun's spectrum to make solar cells more efficient July 27th, 2015

Molecular Machines

Injectable electronics: New system holds promise for basic neuroscience, treatment of neuro-degenerative diseases June 8th, 2015

One step closer to a single-molecule device: Columbia Engineering researchers first to create a single-molecule diode -- the ultimate in miniaturization for electronic devices -- with potential for real-world applications May 25th, 2015

UCLA nanoscientists are first to model atomic structures of three bacterial nanomachines: Cryo electron microscope enables scientists to explore the frontiers of targeted antibiotics April 21st, 2015

Advances in molecular electronics: Lights on -- molecule on: Researchers from Dresden and Konstanz succeed in light-controlled molecule switching April 20th, 2015

Chip Technology

This could replace your silicon computer chips: A new semiconductor material made from black phosphorus may be a candidate to replace silicon in future tech July 30th, 2015

March 2016; 6th Int'l Conference on Nanostructures in Iran July 29th, 2015

Meet the high-performance single-molecule diode: Major milestone in molecular electronics scored by Berkeley Lab and Columbia University team July 29th, 2015

Short wavelength plasmons observed in nanotubes: Berkeley Lab researchers create Ludinger liquid plasmons in metallic SWNTs July 28th, 2015

Nanoelectronics

Superfast fluorescence sets new speed record: Plasmonic device has speed and efficiency to serve optical computers July 27th, 2015

Spintronics: Molecules stabilizing magnetism: Organic molecules fixing the magnetic orientation of a cobalt surface/ building block for a compact and low-cost storage technology/ publication in Nature Materials July 25th, 2015

ORNL researchers make scalable arrays of 'building blocks' for ultrathin electronics July 22nd, 2015

An easy, scalable and direct method for synthesizing graphene in silicon microelectronics: Korean researchers grow 4-inch diameter, high-quality, multi-layer graphene on desired silicon substrates, an important step for harnessing graphene in commercial silicon microelectronics July 21st, 2015

Announcements

Self-assembling, biomimetic membranes may aid water filtration August 1st, 2015

Transparent, electrically conductive network of encapsulated silver nanowires: A novel electrode for optoelectronics August 1st, 2015

Harris & Harris Group Portfolio Company, HZO, Announces Partnerships with Dell and Motorola August 1st, 2015

Advances and Applications in Biosensing, Sensor Power, and Sensor R&D to be Covered at Sensors Global Summit August 1st, 2015

Tools

Heating and cooling with light leads to ultrafast DNA diagnostics July 31st, 2015

Take a trip through the brain July 30th, 2015

Publication on Atomic Force Microscopy based nanoscale IR Spectroscopy (AFM-IR) persists as a 2015 top downloaded paper July 29th, 2015

Nanometrics Announces Upcoming Investor Events July 28th, 2015

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