Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Nanomembranes promise new materials for advanced electronics

Abstract:
The camera in your phone collects light on silicon and translate that information into digital bits. One of the reasons those cameras and phones continue to improve is that researchers are developing new materials that absorb more light, use less power, and are less expensive to produce.

Nanomembranes promise new materials for advanced electronics

Madison, WI | Posted on July 21st, 2011

Now, University of Wisconsin-Madison materials science and engineering researchers have introduced innovations that could make possible a wide range of new crystalline materials. Writing in the June 8 web issue of the American Chemical Society journal ACS Nano, Research Assistants Deborah Paskiewicz and Boy Tanto along with Scientist Donald Savage and Erwin W. Mueller Professor and Bascom Professor of Surface Science Max Lagally, describe a new approach for using thin sheets of semiconductor known as nanomembranes.

Controlled stretching of these membranes via epitaxy allows the team to fabricate fully elastically relaxed silicon germanium nanomembranes for use as growth substrates for new materials. The team grew defect-free silicon germanium layers with any desired germanium concentration on silicon substrates and then released the silicon germanium layers from the rigid silicon, allowing them to relax completely as free-standing nanomaterials. The silicon germanium film is then transferred to a new host and bonded there. From this stage, a defect-free bulk silicon germanium crystal can be grown (something not possible with current technology), or the silicon germanium membrane can be used as a unique substrate to grow other materials.

Epitaxy, growth that controls the arrangement of atoms in thin layers on a substrate, is the fundamental technology underlying the semiconductor industry's use of these new materials. By combining elements, researchers can grow materials with unique properties that make possible new kinds of sensors or high speed, low-power, efficient advanced electronics. It is the ability to grow them without detrimental defects that makes these alloys useful to the semiconductor industry. However, making high-quality crystals that combine two or more elements faces significant limitations that have vexed researchers for decades.

"Many materials consisting of more than one element simply cannot be used. The distances between atoms are not the same," says Lagally. "When one begins to grow such a layer, the atoms start to interfere with each other and very soon the material no longer can grow as just one crystal because it starts to have defects in it. Eventually, it breaks up into small crystals and becomes polycrystalline, or even cracks."

In addition to its use in the semiconductor industry, silicon germanium is important to the nascent field of quantum computing. A quantum computer makes direct use of quantum mechanical phenomena such as superposition and entanglement to perform calculations. Current computers are limited to two states; on and off, or zero and one. With superposition, quantum computers encode information as quantum bits. These bits represent the varying states and inner workings of atoms and electrons. By manipulating these multiple states simultaneously, a large-scale quantum computer, if it can be built, could be millions of times more powerful than today's most powerful classical supercomputer.

"UW-Madison Physics Professor Mark Eriksson uses silicon germanium to make two-dimensional electron gases. A ‘two-dimensional electron gas' is a layer of a semiconductor in which charges are able to move freely over large distances, in analogy with atoms in a real gas, except confined to a thin layer and hence two-dimensional. For quantum computing, this 2-D electron gas is formed in a strained-silicon layer grown on a silicon germanium substrate. Electrodes put on top of a structure containing the 2-D electron gas in the strained-silicon layer allow one to move and control single electrons, turning regions of the quantum well into ‘electron buckets,' if you will, that are defined by the electric fields from the top electrodes,' says Lagally.

A major obstacle to developing a quantum computer is creating multiple quantum buckets as similar as possible. To make rapid progress, researchers need low-defect and consistent materials.

"With the silicon germanium substrates we have been using, the electrostatic fields can be quite uncertain because of the defects in the substrate," says Lagally. "We believe our new process can fix that. Because the substrate material is uniform, without defects, it should bring more predictability and control to Mark's efforts."

Beyond silicon germanium, Lagally says the process should work for a wide range of exotic materials that cannot be grown in bulk but have interesting properties. Materials Science and Engineering Associate Professor Paul Evans develops new ways to probe and apply these materials.

"The thin defect-free substrates that can be produced by transferring and relaxing these layers present exciting opportunities in the growth of materials beyond silicon and other traditional semiconductors," Evans says. "With this approach, it will be possible to produce defect-free substrates of materials for which no high-crystalline quality bulk materials exist. In complex oxides, this can lead to thin substrates that stabilize specific ferroelectric or dielectric phases. That could lead to better oscillators, sensors and optical devices, that are important to the cell phones, cameras and computers we use everyday."

This research is funded by the U.S. Department of Energy with facilities support by the National Science Foundation and the UW-Madison Materials Research Science and Engineering Center as well as the NSF Graduate Research Fellowship Program.

####

For more information, please click here

Contacts:
Jim Beal

College of Engineering
1415 Engineering Drive
Madison, WI 53706

Copyright © University of Wisconsin-Madison

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

A new, tunable device for spintronics: An international team of scientists including physicist Jairo Sinova from the University of Mainz realises a tunable spin-charge converter made of GaAs August 29th, 2014

Nanoscale assembly line August 29th, 2014

New analytical technology reveals 'nanomechanical' surface traits August 29th, 2014

New Vice President Takes Helm at CNSE CMOST: Catherine Gilbert To Lead CNSE Children’s Museum of Science and Technology Through Expansion And Relocation August 29th, 2014

Govt.-Legislation/Regulation/Funding/Policy

New analytical technology reveals 'nanomechanical' surface traits August 29th, 2014

New Vice President Takes Helm at CNSE CMOST: Catherine Gilbert To Lead CNSE Children’s Museum of Science and Technology Through Expansion And Relocation August 29th, 2014

Leading European communications companies and research organizations have launched an EU project developing the future 5th Generation cellular mobile networks August 28th, 2014

New technique uses fraction of measurements to efficiently find quantum wave functions August 28th, 2014

Chip Technology

New analytical technology reveals 'nanomechanical' surface traits August 29th, 2014

Fonon Announces 3D Metal Sintering Technology: Emerging Additive Nano Powder Manufacturing Technology August 28th, 2014

RMIT delivers $30m boost to micro and nano-tech August 26th, 2014

Competition for Graphene: Berkeley Lab Researchers Demonstrate Ultrafast Charge Transfer in New Family of 2D Semiconductors August 26th, 2014

Nanoelectronics

Competition for Graphene: Berkeley Lab Researchers Demonstrate Ultrafast Charge Transfer in New Family of 2D Semiconductors August 26th, 2014

A*STAR and industry form S$200M semiconductor R&D July 25th, 2014

A Crystal Wedding in the Nanocosmos July 23rd, 2014

3-D nanostructure could benefit nanoelectronics, gas storage: Rice U. researchers predict functional advantages of 3-D boron nitride July 15th, 2014

Discoveries

A new, tunable device for spintronics: An international team of scientists including physicist Jairo Sinova from the University of Mainz realises a tunable spin-charge converter made of GaAs August 29th, 2014

Nanoscale assembly line August 29th, 2014

Copper shines as flexible conductor August 29th, 2014

Novel 'butterfly' molecule could build new sensors, photoenergy conversion devices August 28th, 2014

Announcements

A new, tunable device for spintronics: An international team of scientists including physicist Jairo Sinova from the University of Mainz realises a tunable spin-charge converter made of GaAs August 29th, 2014

Nanoscale assembly line August 29th, 2014

New analytical technology reveals 'nanomechanical' surface traits August 29th, 2014

New Vice President Takes Helm at CNSE CMOST: Catherine Gilbert To Lead CNSE Children’s Museum of Science and Technology Through Expansion And Relocation August 29th, 2014

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE