Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Scientists find technique to improve carbon superlattices for quantum electronic devices: In a paradigm shift from conventional electronic devices, exploiting the quantum properties of superlattices holds the promise of developing new technologies

A schematic atomic diagram of a quantum well made from amorphous carbon layers. The blue atoms represent amorphous carbon with a high percentage of diamond-like carbon. The maroon atoms represent amorphous carbon which is graphite-like. The diamond-like regions have a high potential (diamond is insulating) while the graphite-like regions are more metallic. This creates a quantum well as electrons are confined within the graphite-like region due to the relatively high potential in the diamond-like regions. Superlattices are made up of a series of quantum wells.
CREDIT
Wits University
A schematic atomic diagram of a quantum well made from amorphous carbon layers. The blue atoms represent amorphous carbon with a high percentage of diamond-like carbon. The maroon atoms represent amorphous carbon which is graphite-like. The diamond-like regions have a high potential (diamond is insulating) while the graphite-like regions are more metallic. This creates a quantum well as electrons are confined within the graphite-like region due to the relatively high potential in the diamond-like regions. Superlattices are made up of a series of quantum wells. CREDIT Wits University

Abstract:
Researchers at the Nanoscale Transport Physics Laboratory from the School of Physics at the University of the Witwatersrand have found a technique to improve carbon superlattices for quantum electronic device applications. Superlattices are made up of alternating layers of very thin semiconductors, just a few nanometers thick. These layers are so thin that the physics of these devices is governed by quantum mechanics, where electrons behave like waves. In a paradigm shift from conventional electronic devices, exploiting the quantum properties of superlattices holds the promise of developing new technologies.

Scientists find technique to improve carbon superlattices for quantum electronic devices: In a paradigm shift from conventional electronic devices, exploiting the quantum properties of superlattices holds the promise of developing new technologies

Johannesburg, South Africa | Posted on October 20th, 2016

The group, headed by Professor Somnath Bhattacharyya has been working for the past 10 years on developing carbon-based nano-electronic devices.

"Carbon is the future in the electronics field and it soon will be challenging many other semiconductors, including silicon," says Bhattacharyya.

The physics of carbon superlattices is more complex than that of crystalline superlattices (such as gallium arsenide), since the material is amorphous and carbon atoms tend to form chains and networks. The Wits group, in association with researchers at the University of Surrey in the UK, has developed a detailed theoretical approach to understand the experimental data obtained from carbon devices. The paper has been published in Scientific Reports (Nature Publishing Group) on 19 October.

"This work provides an understanding of the fundamental quantum properties of carbon superlattices, which we can now use to design quantum devices for specific applications," says lead author, Wits PhD student, Ross McIntosh. "Our work provides strong impetus for future studies of the high-frequency electronic and optoelectronic properties of carbon superlattices".

Through their work, the group reported one of the first theoretical models that can explain the fundamental electronic transport properties in disordered carbon superlattices.

Bhattacharyya started looking at the use of carbon for semiconductor applications almost 10 years ago, before he joined Wits University, when he and co-authors from the University of Surrey developed and demonstrated negative differential resistance and excellent high-frequency properties of a quantum device made up of amorphous carbon layers. This work was published in Nature Materials in 2006.

McIntosh undertook the opportunity at honours level to measure the electrical properties of carbon superlattice devices. Now, as a PhD student and having worked extensively with theoretician Dr. Mikhail V. Katkov, he has extended the theoretical framework and developed a technique to calculate the transport properties of these devices.

Bhattacharyya believes this work will have immense importance in developing Carbon-based high-frequency devices.

"It will open not only fundamental studies in Carbon materials, but it will also have industrial applications in the electronic and optoelectronic device sector," he says.

Superlattices are currently used as state of the art high frequency oscillators and amplifiers and are beginning to find use in optoelectronics as detectors and emitters in the terahertz regime. While the high frequency electrical and optoelectronic properties of conventional semiconductors are limited by the dopants used to modify their electronic properties, the properties of superlattices can be tuned over a much wider range to create devices which operate in regimes where conventional devices cannot.

Superlattice electronic devices can operate at higher frequencies and optoelectronic devices can operate at lower frequencies than their conventional counterparts. The lack of terahertz emitters and detectors has resulted in a gap in that region of the electromagnetic spectrum (known as the "terahertz gap"), which is a significant limitation, as many biological molecules are active in this regime. This also limits terahertz radio astronomy.

Amorphous Carbon devices are extremely strong, can operate at high voltages and can be developed in most laboratories in the world, without sophisticated nano-fabrication facilities. New Carbon-based devices could find application in biology, space technology, science infrastructure such as the Square Kilometre Array (SKA) telescope in South Africa, and new microwave detectors.

"What was lacking earlier was an understanding of device modelling. If we have a model, we can improve the device quality, and that is what we now have," says Bhattacharyya.

####

About University of the Witwatersran
The Wits Nanoscale Transport Physics Laboratory (NSTPL) was established in 2009 under the leadership of Bhattacharyya when Professor Joćo Rodrigues was the Head of the School of Physics at the University of the Witwatersrand, South Africa. The department is known as a leading Physics school in the African continent, having one of the largest academic staff complements on a single campus. Since the opening of the laboratory, the NSTPL has gone from strength to strength in establishing a facility that houses world class fabrication and measurement equipment, an initiative strongly supported by research entities such as the NRF, CSIR, Wits Research Office and DST/NRF Centre of Excellence in Strong Materials.

The NSTPL is well equipped with various sophisticated synthesis facilities, as well as a cryogenic micro-manipulated probe station to conduct sensitive quantum transport measurements at temperatures near absolute zero. The NSTPL also houses a fully operational electron beam lithography scanning electron microscope, used to fabricate nanoscale devices based on these carbon materials.

Some noteworthy current projects include the fabrication of spintronic devices using supramolecular Gd-functionalized carbon nanotubes, the fabrication of graphene field effect transistors and most recently the study of the unconventional superconductivity observed in boron-doped diamond. The NSTPL group has also published a number of papers on theoretical investigations, led by Dr Mikhail Katkov and Dr Dmitry Churochkin, on the role of disorder on the quantum transport in carbon systems. These various topics form part of the broader direction the group has taken, that being, investigating the physics of carbon materials in the hopes of finding application in quantum information systems as well as detector devices valuable for space exploration.

For more information, please click here

Contacts:
Schalk Mouton

27-827-399-637

Copyright © University of the Witwatersran

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 News Press

Quantum Physics

The speed limit for intra-chip communications in microprocessors of the future January 23rd, 2017

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

News and information

The speed limit for intra-chip communications in microprocessors of the future January 23rd, 2017

New, old science combine to make faster medical test: Nanoparticles and Faraday rotation allow faster diagnoses January 23rd, 2017

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

Possible Futures

The speed limit for intra-chip communications in microprocessors of the future January 23rd, 2017

New, old science combine to make faster medical test: Nanoparticles and Faraday rotation allow faster diagnoses January 23rd, 2017

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

Spintronics

First experimental proof of a 70 year old physics theory: First observation of magnetic phase transition in 2-D materials, as predicted by the Nobel winner Onsager in 1943 January 6th, 2017

Investigations of the skyrmion Hall effect reveal surprising results: One step further towards the application of skyrmions in spintronic devices December 28th, 2016

Electron highway inside crystal December 12th, 2016

Making spintronic neurons sing in unison November 18th, 2016

Chip Technology

The speed limit for intra-chip communications in microprocessors of the future January 23rd, 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

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

Nanotubes/Buckyballs/Fullerenes

Captured on video: DNA nanotubes build a bridge between 2 molecular posts: Research may lead to new lines of direct communication with cells January 9th, 2017

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

WPI researchers build liquid biopsy chip that detects metastatic cancer cells in blood December 15th, 2016

Infrared instrumentation leader secures exclusive use of Vantablack coating December 5th, 2016

Quantum Computing

Seeing the quantum future... literally: What if big data could help you see the future and prevent your mobile phone from breaking before it happened? January 16th, 2017

NIST physicists 'squeeze' light to cool microscopic drum below quantum limit January 12th, 2017

First experimental proof of a 70 year old physics theory: First observation of magnetic phase transition in 2-D materials, as predicted by the Nobel winner Onsager in 1943 January 6th, 2017

Diamonds are technologists' best friends: Researchers from the Lomonosov Moscow State University have grown needle- and thread-like diamonds and studied their useful properties December 30th, 2016

Nanoelectronics

The speed limit for intra-chip communications in microprocessors of the future January 23rd, 2017

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

Discoveries

The speed limit for intra-chip communications in microprocessors of the future January 23rd, 2017

New, old science combine to make faster medical test: Nanoparticles and Faraday rotation allow faster diagnoses January 23rd, 2017

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

Announcements

The speed limit for intra-chip communications in microprocessors of the future January 23rd, 2017

New, old science combine to make faster medical test: Nanoparticles and Faraday rotation allow faster diagnoses January 23rd, 2017

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

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

The speed limit for intra-chip communications in microprocessors of the future January 23rd, 2017

New, old science combine to make faster medical test: Nanoparticles and Faraday rotation allow faster diagnoses January 23rd, 2017

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

Aerospace/Space

National Space Society Congratulates SpaceX on the Falcon 9's Return to Flight January 19th, 2017

Eric Berger Wins the National Space Society's 2017 Space Pioneer Award for Mass Media January 19th, 2017

Infrared instrumentation leader secures exclusive use of Vantablack coating December 5th, 2016

New records set up with 'Screws of Light' November 20th, 2016

Quantum nanoscience

The speed limit for intra-chip communications in microprocessors of the future January 23rd, 2017

First experimental proof of a 70 year old physics theory: First observation of magnetic phase transition in 2-D materials, as predicted by the Nobel winner Onsager in 1943 January 6th, 2017

Quantum simulation technique yields topological soliton state in SSH model January 3rd, 2017

Diamonds are technologists' best friends: Researchers from the Lomonosov Moscow State University have grown needle- and thread-like diamonds and studied their useful properties December 30th, 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