Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists craft atomically seamless, thinnest-possible semiconductor junctions

27.08.2014

Scientists have developed what they believe is the thinnest-possible semiconductor, a new class of nanoscale materials made in sheets only three atoms thick.

The University of Washington researchers have demonstrated that two of these single-layer semiconductor materials can be connected in an atomically seamless fashion known as a heterojunction. This result could be the basis for next-generation flexible and transparent computing, better light-emitting diodes, or LEDs, and solar technologies.


U of Washington

This photoluminescence intensity map shows a typical piece of the lateral heterostructures. The junction region produces an enhanced light emission, indicating its application potential in optoelectronics.

“Heterojunctions are fundamental elements of electronic and photonic devices,” said senior author Xiaodong Xu, a UW assistant professor of materials science and engineering and of physics. “Our experimental demonstration of such junctions between two-dimensional materials should enable new kinds of transistors, LEDs, nanolasers, and solar cells to be developed for highly integrated electronic and optical circuits within a single atomic plane.”

The research was published online this week in Nature Materials.

The researchers discovered that two flat semiconductor materials can be connected edge-to-edge with crystalline perfection. They worked with two single-layer, or monolayer, materials – molybdenum diselenide and tungsten diselenide – that have very similar structures, which was key to creating the composite two-dimensional semiconductor.

Collaborators from the electron microscopy center at the University of Warwick in England found that all the atoms in both materials formed a single honeycomb lattice structure, without any distortions or discontinuities. This provides the strongest possible link between two single-layer materials, necessary for flexible devices. Within the same family of materials it is feasible that researchers could bond other pairs together in the same way.

The researchers created the junctions in a small furnace at the UW. First, they inserted a powder mixture of the two materials into a chamber heated to 900 degrees Celsius (1,652 F). Hydrogen gas was then passed through the chamber and the evaporated atoms from one of the materials were carried toward a cooler region of the tube and deposited as single-layer crystals in the shape of triangles.

After a while, evaporated atoms from the second material then attached to the edges of the triangle to create a seamless semiconducting heterojunction.

“This is a scalable technique,” said Sanfeng Wu, a UW doctoral student in physics and one of the lead authors. “Because the materials have different properties, they evaporate and separate at different times automatically. The second material forms around the first triangle that just previously formed. That’s why these lattices are so beautifully connected.”

With a larger furnace, it would be possible to mass-produce sheets of these semiconductor heterostructures, the researchers said. On a small scale, it takes about five minutes to grow the crystals, with up to two hours of heating and cooling time.

“We are very excited about the new science and engineering opportunities provided by these novel structures,” said senior author David Cobden, a UW professor of physics. “In the future, combinations of two-dimensional materials may be integrated together in this way to form all kinds of interesting electronic structures such as in-plane quantum wells and quantum wires, superlattices, fully functioning transistors, and even complete electronic circuits.”

The researchers have already demonstrated that the junction interacts with light much more strongly than the rest of the monolayer, which is encouraging for optoelectric and photonic applications like solar cells.

Other co-authors are Chunming Huang and Pasqual Rivera of UW physics; Ana Sanchez, Richard Beanland and Jonathan Peters at the University of Warwick; Jason Ross of UW materials science and engineering; and Wang Yao, a theoretical physicist of the University of Hong Kong.

This research was funded by the U.S. Department of Energy, the UW’s Clean Energy Institute, the Research Grant Council of Hong Kong, the University Grants Committee of Hong Kong, the Croucher Foundation, the Science City Research Alliance and the Higher Education Funding Council for England’s Strategic Development Fund.

###

For more information, contact Wu at swu02@uw.edu.

Grant numbers: U.S. Department of Energy, Basic Energy Sciences, Materials Sciences and Engineering Division (DE-SC0008145) (DE-SC0002197).

Michelle Ma | Eurek Alert!
Further information:
http://www.washington.edu/news/2014/08/26/scientists-craft-atomically-seamless-thinnest-possible-semiconductor-junctions/

Further reports about: Energy Heterojunctions LEDs crystals materials monolayer physics semiconductor structures transistors triangle

More articles from Materials Sciences:

nachricht Switched-on DNA
20.02.2017 | Arizona State University

nachricht Using a simple, scalable method, a material that can be used as a sensor is developed
15.02.2017 | University of the Basque Country

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

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...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

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

Impacts of mass coral die-off on Indian Ocean reefs revealed

21.02.2017 | Earth Sciences

Novel breast tomosynthesis technique reduces screening recall rate

21.02.2017 | Medical Engineering

Use your Voice – and Smart Homes will “LISTEN”

21.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>