(Press-News.org) An international team of researchers has taken a significant step towards understanding the fundamental properties of the two-dimensional material silicene by showing that it can remain stable in the presence of oxygen.
In a study published today, 12 August, in IOP Publishing's journal 2D Materials, the researchers have shown that thick, multilayers of silicene can be isolated from its parent material silicon and remain intact when exposed to air for at least 24 hours.
It is the first time that such a feat has been achieved and will allow scientists to further probe the material and exploit the properties that have made silicene a promising material in the electronics industry.
Silicene is made from single, honeycomb-shaped layers of silicon that are just one atom thick. At the moment, silicene must be produced in a vacuum to avoid any contact with oxygen, which could completely destroy the formation of the single layers.
Silicene must also be "grown" on a surface that matches its natural structure — silver is the leading candidate. To create silicene, a wafer of silicon is heated to high temperatures, forcing single silicon atoms to evaporate and land on the silver substrate, forming the single layer.
Silicene can also be transformed from a 2D material into a 3D material by stacking more and more single layers on top of each other. However, previous research has demonstrated that silicene has "suicidal tendencies" and always reverts back to silicon as more layers are added, because a silicon structure is more stable.
In this new study, an international team of researchers based in Italy and France fabricated multilayers of silicene using a silver substrate kept at a temperature of 470 K and a solid silicon source, which was heated to 1470 K. A total of 43 monolayers of silicene were deposited onto the substrate.
Once fabricated, the researchers observed that a very thin layer of oxidation had formed on top of the multi-layered stack of monolayers; however, it was shown that this preserved the integrity of the stack, acting like a protective layer.
The stack of monolayers remained preserved for at least 24 hours in open air, in which time the researchers were able to use x-ray diffraction and Raman spectroscopy to confirm that the material was in fact silicene and not ordinary silicon.
Lead author of the study Paola De Padova, from Consiglio Nazionale delle Ricerche in Italy, said: "These results are significant as we have shown that it is possible to obtain a silicon-based 2D material, which up until a couple of years ago was deemed inconceivable.
"Our present study shows that multi-layered silicene is more conductive than single-layered silicene, and therefore opens up the possibility of using it throughout the silicon microelectronics industry. In particular, we envisage the material being used as gate in a silicene-based MOSFET, which is the most commonly used transistor in digital and analog circuits.
"We are currently studying the possibility of growing multi-layered silicene directly onto semiconductor substrates to explore the joint superconducting properties."
INFORMATION:
This paper can be downloaded from http://iopscience.iop.org/2053-1583/1/2/021003/article
Contact
For further information, a full draft of the journal paper or contact with one of the researchers, contact IOP Press Officer, Michael Bishop: Tel: 0117 930 1032 E-mail: michael.bishop@iop.org For more information on how to use the embargoed material above, please refer to our embargo policy.
IOP Publishing Journalist Area
The IOP Publishing Journalist Area gives journalists access to embargoed press releases, advanced copies of papers, supplementary images and videos. In addition to this, a weekly news digest is uploaded into the Journalist Area every Friday, highlighting a selection of newsworthy papers set to be published in the following week. Login details also give free access to IOPscience, IOP Publishing's journal platform. To apply for a free subscription to this service, please email Michael Bishop, IOP Press Officer, michael.bishop@iop.org, with your name, organisation, address and a preferred username.
24h stability of thick multilayer silicene in air
The published version of the paper '24h stability of thick multilayer silicene in air' (Paola De Padova et al 2014 2D Mater. 1 021003) will be freely available online from Tuesday 12 August. It will be available at http://iopscience.iop.org/2053-1583/1/2/021003/article.
2D Materials
2D Materials is a multidisciplinary, electronic-only journal devoted to publishing fundamental and applied research of the highest quality and impact covering all aspects of graphene and related two-dimensional materials.
IOP Publishing
IOP Publishing provides publications through which leading-edge scientific research is distributed worldwide.
Beyond our traditional journals programme, we make high-value scientific information easily accessible through an ever-evolving portfolio of books, community websites, magazines, conference proceedings and a multitude of electronic services.
IOP Publishing is central to the Institute of Physics, a not-for-profit society. Any financial surplus earned by IOP Publishing goes to support science through the activities of the Institute.
Go to ioppublishing.org.
Access to Research
Access to Research is an initiative through which the UK public can gain free, walk-in access to a wide range of academic articles and research at their local library. This article is freely available through this initiative. For more information, go to http://www.accesstoresearch.org.uk
The Institute of Physics
The Institute of Physics is a leading scientific society. We are a charitable organisation with a worldwide membership of more than 50,000, working together to advance physics education, research and application.
We engage with policymakers and the general public to develop awareness and understanding of the value of physics and, through IOP Publishing, we are world leaders in professional scientific communications.
In September 2013, we launched our first fundraising campaign. Our campaign, Opportunity Physics, offers you the chance to support the work that we do.
Researchers prove stability of wonder material silicene
2014-08-12
ELSE PRESS RELEASES FROM THIS DATE:
Prognosis of pneumonia: value of respiratory rate often overlooked
2014-08-12
Pneumonia – a severe lung infection – is the most common disease calling for hospital admission. More than one out of ten pneumonia patients die of the disease. Thus it is vital to accurately predict and closely monitor the clinical course. Here, measuring the respiratory rate – the number of breaths a person takes in a minute – provides valuable information. However, far too little use is still being made of this vital sign in clinical practice, as Richard Strauß and co-authors conclude in their recent study in Deutsches Ärzteblatt (Dtsch Arztebl Int 2014; 111: 503).
The ...
Hijacking the brain's blood supply: tumor discovery could aid treatment
2014-08-12
ANN ARBOR, Mich. — Dangerous brain tumors hijack the brain's existing blood supply throughout their progression, by growing only within narrow potential spaces between and along the brain's thousands of small blood vessels, new research shows for the first time.
The findings contradict the concept that brain tumors need to grow their own blood vessels to keep themselves growing – and help explain why drugs that aim to stop growth of the new blood vessels have failed in clinical trials to extend the lives of patients with the worst brain tumors.
In fact, trying to ...
Lead released from African cookware contaminates food
2014-08-12
San Francisco and Yaoundé – Lead levels in foods prepared in aluminum pots from Cameroon exceed U.S. guidelines for lead consumption according to a new study published this month. A typical serving contains almost 200 times more lead than California's Maximum Allowable Dose Level (MADL) of 0.5 micrograms per day.
Researchers at Ashland University and Occupational Knowledge International tested 29 samples of aluminum cookware made in Cameroon and found almost all had considerable lead content. This cookware is common throughout Africa and Asia and is made from recycled ...
Changes in motor function in the unaffected hand of stroke patients should not be ignored
2014-08-12
With effective rehabilitation, stroke patients can partially regain their motor control and continue their activities of daily living. Motor function changes in the unaffected hand of stroke patients with hemiplegia. However, these changes are often ignored by clinicians owing to the extent of motor disability of the affected hand. Research group at Shanghai University of Sport, China led by Prof. Zhusheng Yu based on finger tapping frequency and Lind-mark hand function score have found that the motor function of unaffected hands in stroke patients was poorer than that ...
Neuroprotective effect of tongxinluo: a PET imaging study in small animals
2014-08-12
Tongxinluo has been widely used in China for the treatment of acute stroke and for neuroprotection. Research group at Encephalopathy Center, Guangdong Provincial Hospital of Traditional Chinese Medicine, China intragastrically administered Tongxinluo superfine powder suspension or its vehicle to rats for 5 successive days before middle cerebral artery occlusion. There are many advantages of using small animal PET for drug research. First, the results of the study in vitro cannot be directly applied to human studies, while small animal PET imaging methods and results can ...
ASU-Mayo researchers use calcium isotope analysis to predict myeloma progression
2014-08-12
TEMPE, Ariz. – A team of researchers from Arizona State University and Mayo Clinic is showing how a staple of Earth science research can be used in biomedical settings to predict the course of disease.
The researchers tested a new approach to detecting bone loss in cancer patients by using calcium isotope analysis to predict whether myeloma patients are at risk for developing bone lesions, a hallmark of the disease.
They believe they have a promising technique that could be used to chart the progression of multiple myeloma, a lethal disease that eventually impacts ...
Neutrino detectors could help curb nuclear weapons activity
2014-08-12
Physicists at the Large Hadron Collider in Switzerland and even in the fictional world of CBS' "The Big Bang Theory" look to subatomic particles called neutrinos to answer the big questions about the universe.
Now, a group of scientists led by a physics professor with the College of Science at Virginia Tech are asking whether the neutrino could provide the world with clues about nuclear proliferation in Iran and other political hotspots.
Neutrinos are produced by the decay of radioactive elements, and nuclear reactors produce large amounts of neutrinos that cannot ...
Focal blood-brain-barrier disruption with high-frequency pulsed electric fields
2014-08-12
A team of researchers from the Virginia Tech-Wake Forest University School of Biomedical Engineering and Sciences have developed a new way of using electricity to open the blood-brain-barrier (BBB). The Vascular Enabled Integrated Nanosecond pulse (VEIN pulse) procedure consists of inserting minimally invasive needle electrodes into the diseased tissue and applying multiple bursts of nanosecond pulses with alternating polarity. It is thought that the bursts disrupt tight junction proteins responsible for maintaining the integrity of the BBB without causing damage to the ...
A highly sensitive microsphere-based assay for early detection of Type I diabetes
2014-08-12
A team of researchers from the Center for Engineering in Medicine at the Massachusetts General Hospital have developed a novel fluorescence-based assay for sensitive detection of antibodies within microliter volume serum samples. This new assay is at least 50 times more sensitive than the traditional radioimmunoassay (RIA), which is the gold standard currently used in the clinic. This new technology is particularly attractive for immunological assays as it allows: 1) use of very small volumes of sample reagents (5 ¦ÌL), and 2) use of traditional analytical systems such ...
Biomarker could reveal why some develop post-traumatic stress disorder
2014-08-12
(NEW YORK – August 11) Blood expression levels of genes targeted by the stress hormones called glucocorticoids could be a physical measure, or biomarker, of risk for developing Post-Traumatic Stress Disorder (PTSD), according to a study conducted in rats by researchers at the Icahn School of Medicine at Mount Sinai and published August 11 in Proceedings of the National Academy of Sciences (PNAS). That also makes the steroid hormones' receptor, the glucocorticoid receptor, a potential target for new drugs.
Post-Traumatic Stress Disorder (PTSD) is triggered by a terrifying ...