Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists from the UAB and ICMAB achieve unprecedented control of formation of nanostructures

08.05.2002


Atomic Force Microscope image of nanoislands


A team of researchers from the Universitat Autònoma de Barcelona, together with researchers from ICMAB (CSIC) and other Russian and Ukrainian scientists, have discovered an unprecedented method for accurately controlling the formation of nanometric structures made of semiconducting material in the form of islets, using promising optoelectronic applications in the most advanced communication technology. The discovery was featured as a cover story by the prestigious Nanotechnology magazine.

One of the areas that is currently being most thoroughly researched with respect to future applications is the manipulation of surfaces on a nanometric scale, up to the point of practically constructing and manipulating structures atom by atom, and whereby the quantum effects could give these materials new properties, with revolutionary applications for nanoelectronics, optoelectronics and computing. One of these structures is the so-called quantum dot, in which electrons lose their capacity for mobility in spatial dimensions and become confined to a zero dimension (a dot). At the moment, the experiments with semiconductor materials most similar to quantum dots are the formation of nanoilles, semiconductor islets of several tens of nanometers of diameter and height. These islets can be produced using lithographic techniques, “printing” them onto the surface of a substrate, but for a decade now, scientists have been working on a new, and more efficient and stable, method for constructing them: the spontaneous formation of nanoilles.

Now, a team of researchers from the Universitat Autònoma de Barcelona, together with researchers from the Institute of the Science of Materials in Barcelona (a CSIC institute on the UAB campus), the Institute of Microstructure Physics in Nizhny Novgorod (Russia) and the Institute of Semiconductor Physics in Kiev (Ukraine), have developed unprecedented accuracy in the control of the growth of nanoilles. These researchers have made a detailed study of the spontaneous formation of SiGe nanoilles (semiconductor material) by depositing thin layers of geranium atoms onto silicon substrates, and have observed, for the first time, how they separately affect the thickness of the layers of geranium and the temperature of formation of nanoilles in their distribution, composition and in two possible forms: pyramid or rounded.



The team of researchers has developed an unprecedented level of control of the distribution, shape and composition of the SiGe nanoilles, such that by varying the thickness of the layers of geranium and the temperature of the silicon substrate they can obtain, at will, large densities of small pyramid islets, large round islets distributed at much lower densities or even a uniform mixture of pyramid and rounded islets. As for the control of the composition of the islets’ SiGe semiconductor material, the researchers have observed that as temperature is increased, so does the silicon content, independently of the form and distribution of the nanoilles.

This research was later considered worthy of being the cover story in the prestigious Nanotechnology magazine, and may have important implications for the fields of nanoelectronics and optoelectronics, as semiconductor lasers (such as those used in ‘laser pointers’) manufactured with this material could emit light in a far wider range of colours than at present. It is expected that this discovery will improve the transmission of information via fibre optics and in electronic circuits, the basis of new communication technologies.

The researchers are now working on the formation of other quantum nanostructures, most particularly semiconductor nanolagoons, which are formed spontaneously on depositing layers of cadmium selenium (CdSe) onto zinc selenium (ZnSe) substrates.

Octavi López Coronado | alphagalileo

More articles from Physics and Astronomy:

nachricht Quantum optics allows us to abandon expensive lasers in spectroscopy
22.11.2017 | Lomonosov Moscow State University

nachricht Nano-watch has steady hands
22.11.2017 | University of Vienna

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Corporate coworking as a driver of innovation

22.11.2017 | Business and Finance

PPPL scientists deliver new high-resolution diagnostic to national laser facility

22.11.2017 | Physics and Astronomy

Quantum optics allows us to abandon expensive lasers in spectroscopy

22.11.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>