Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

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

Traffic jam in empty space: New success for Konstanz physicists in studying the quantum vacuum January 22nd, 2017

A big nano boost for solar cells: Kyoto University and Osaka Gas effort doubles current efficiencies January 21st, 2017

Explaining how 2-D materials break at the atomic level January 20th, 2017

New research helps to meet the challenges of nanotechnology: Research helps to make the most of nanoscale catalytic effects for nanotechnology January 20th, 2017

Imaging

Chemists Cook up New Nanomaterial and Imaging Method: Nanomaterials can store all kinds of things, including energy, drugs and other cargo January 19th, 2017

Distinguishing truth under the surface: electrostatic or mechanic December 31st, 2016

Nanoscale 'conversations' create complex, multi-layered structures: New technique leverages controlled interactions across surfaces to create self-assembled materials with unprecedented complexity December 22nd, 2016

Safe and inexpensive hydrogen production as a future energy source: Osaka University researchers develop efficient 'green' hydrogen production system that operates at room temperature in air December 21st, 2016

Molecular Machines

Micro-bubbles make big impact: Research team develops new ultrasound-powered actuator to develop micro robot November 25th, 2016

Scientists come up with light-driven motors to power nanorobots of the future: Researchers from Russia and Ukraine propose a nanosized motor controlled by a laser with potential applications across the natural sciences and medicine November 11th, 2016

HKU chemists develop world's first light-seeking synthetic Nanorobot November 9th, 2016

Light drives single-molecule nanoroadsters: Rice University scientists part of international team demonstrating untethered 3-wheelers November 4th, 2016

Chip Technology

Explaining how 2-D materials break at the atomic level January 20th, 2017

New research helps to meet the challenges of nanotechnology: Research helps to make the most of nanoscale catalytic effects for nanotechnology January 20th, 2017

Ultra-precise chip-scale sensor detects unprecedentedly small changes at the nanoscale January 20th, 2017

Nanometrics to Announce Fourth Quarter and Full Year Financial Results on February 7, 2017 January 19th, 2017

Nanoelectronics

Nano-chimneys can cool circuits: Rice University scientists calculate tweaks to graphene would form phonon-friendly cones January 4th, 2017

Advance in intense pulsed light sintering opens door to improved electronics manufacturing December 23rd, 2016

Fast track control accelerates switching of quantum bits December 16th, 2016

GLOBALFOUNDRIES Demonstrates Industry-Leading 56Gbps Long-Reach SerDes on Advanced 14nm FinFET Process Technology: Proven ASIC IP solution will enable significant performance and power efficiency improvements for next-generation high-speed applications December 13th, 2016

Announcements

Traffic jam in empty space: New success for Konstanz physicists in studying the quantum vacuum January 22nd, 2017

A big nano boost for solar cells: Kyoto University and Osaka Gas effort doubles current efficiencies January 21st, 2017

A toolkit for transformable materials: How to design materials with reprogrammable shape and function January 20th, 2017

New research helps to meet the challenges of nanotechnology: Research helps to make the most of nanoscale catalytic effects for nanotechnology January 20th, 2017

Tools

Chemists Cook up New Nanomaterial and Imaging Method: Nanomaterials can store all kinds of things, including energy, drugs and other cargo January 19th, 2017

Nanometrics to Announce Fourth Quarter and Full Year Financial Results on February 7, 2017 January 19th, 2017

Distinguishing truth under the surface: electrostatic or mechanic December 31st, 2016

Nanomechanics Inc. Continues Growth in Revenue and Market Penetration: Leading nanoindentation company reports continued growth in revenues and distribution channels on national and international scales December 27th, 2016

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