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 From rocks in Colorado, evidence of a 'chaotic solar system'
23.02.2017 | University of Wisconsin-Madison

nachricht Prediction: More gas-giants will be found orbiting Sun-like stars
22.02.2017 | Carnegie Institution for Science

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: Safe glide at total engine failure with ELA-inside

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded after a glide flight with an Airbus A320 in ditching on the Hudson River. All 155 people on board were saved.

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded...

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

New pop-up strategy inspired by cuts, not folds

27.02.2017 | Materials Sciences

Sandia uses confined nanoparticles to improve hydrogen storage materials performance

27.02.2017 | Interdisciplinary Research

Decoding the genome's cryptic language

27.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>