Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Presto! It’s a semiconductor

05.10.2005


Researchers at the University of Pennsylvania may not have turned lead into gold as alchemists once sought to do, but they did turn lead and selenium nanocrystals into solids with remarkable physical properties. In the October 5 edition of Physical Review Letters, online now, physicists Hugo E. Romero and Marija Drndic describe how they developed am artificial solid that can be transformed from an insulator to a semiconductor.

The Penn physicists are among many modern researchers who have been experimenting with a different way of transforming matter through artificial solids, formed from closely packed nanoscale crystals, also called "quantum dots."

"Essentially, we’re forming artificial solids from artificial atoms – about 10 times larger than real atoms – whose properties we can fine tune on the quantum level," said Drndic, an assistant professor in Penn’s Department of Physics and Astronomy. "Artificial solids are expected to revolutionize the fabrication of electronic devices in the near future, but now we are only beginning to understand their fundamental behavior."



Artificial solids, in general, are constructed by specifically assembling a number of nanocrystals, each composed of only a few thousand atoms, into a closely packed and well-ordered lattice. Previous researchers have demonstrated that quantum dots can be manipulated to change their physical properties, particularly their optical properties. In fact, the blue laser, which will soon be put into use into commercial products, was a result of early research in changing the colors of quantum dots.

"Many of the physical parameters of these crystals, such as their composition, particle size and interparticle coupling, represent knobs that can be individually controlled at nanometer scales," Drndic said. "Variation of any of these parameters translates directly into either subtle or dramatic changes in the collective electronic, optical and magnetic response of the crystal. In this case were able to adjust its electrical properties."

In their study, Drndic and her colleagues looked at the ability of artificial solids to transport electrons. They demonstrated that, by controlling the coupling of artificial atoms within the crystal, they could increase the electrical conductivity of the entire crystal. According to the researchers, this system promises the possibility of designing artificial solids that can be switched through a variety of electronic phase transitions, with little influence from the local environment. Their findings represent a key step towards the fabrication of functional nanocrystal-based devices and circuits.

Quantum dots are more than simply analogous to individual atoms; they also demonstrate quantum effects, like atoms, but on a larger scale. As a tool for research, quantum dots make it possible for physicists to measure, firsthand, some things only described in theory.

"It is this versatility in both experiment and theory that can potentially turn these quantum dot solids into model systems for achieving a general understanding of the electronic structure of solids," Drndic said. "Not only are we making strides in creating a future generation of electronics, but in doing so we are also getting a deeper understanding of the fundamental properties of matter."

Greg Lester | EurekAlert!
Further information:
http://www.upenn.edu

More articles from Physics and Astronomy:

nachricht First Juno science results supported by University of Leicester's Jupiter 'forecast'
26.05.2017 | University of Leicester

nachricht Measured for the first time: Direction of light waves changed by quantum effect
24.05.2017 | Vienna University of Technology

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: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>