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 Only an atom thick: Physicists succeed in measuring mechanical properties of 2D monolayer materials
17.01.2018 | Universität des Saarlandes

nachricht Black hole spin cranks-up radio volume
15.01.2018 | National Institutes of Natural Sciences

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: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

Im Focus: A thermometer for the oceans

Measurement of noble gases in Antarctic ice cores

The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Polymers Based on Boron?

18.01.2018 | Life Sciences

Bioengineered soft microfibers improve T-cell production

18.01.2018 | Life Sciences

World’s oldest known oxygen oasis discovered

18.01.2018 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>