Nanotechnology Produces New Electronic Materials

Short description

STONEY BROOK, NY - The nanotechnology of engineering atomic layer interfaces to produce desired properties, called "improper ferroelectricity" reportedly holds promise for a technological revolution that may compare to the development of modern electronics.

Article body

According to an article in the April 10th issue of Nature, a new artificial material is has been created that may mark the beginning of a revolution in the development of materials for electronic applications.

The new material, called a superlattice, which has a layered structure composed of alternating atomically thin layers of two different oxides (PbTiO3 and SrTiO3) takes on properties radically different than either of the two materials by themselves. According to the article, these properties are a direct consequence of the artificially layered atomic structure, and the interactions at the atomic level interface between the layers.

As stated in the article, Ferroelectrics are useful functional materials, with applications ranging from non-volatile computer memories, to micro-electromechanical machines or infrared detectors. "Improper ferroelectricity" is a kind of property that occurs only rarely in natural materials, with effects that are typically too small to be useful. This new superlattice material shows improper ferroelectricity (a property in neither of the original oxides) at a magnitude around 100 times greater than any naturally occurring improper ferroelectric, creating options for many more real world applications.

According to on of the material's researcher, Dr. Matthew Dawber, "Besides the immediate applications that could be generated by this nanomaterial, this discovery opens a completely new field of investigation and the possibility of new functional materials based on…interface engineering on the atomic scale."

Transition metal oxides are a class of materials that provoke great interest because of the great range of functional properties that they can present (dielectrics, ferroelectrics, piezoelectrics, magnets or superconductors) and the possibilities for integration into numerous devices. The majority of these oxides have a similar structure (referred to as 'perovskite') and recently, researchers have developed the ability to build these materials atomic layer by layer, to attempt to produce new materials with exceptional properties.

source...
Philip Buonpastore
http://pcdandf.com

 

Researchers create the first 'nanotrees'

Short description

Since scientists learned to make nanowires, the tiny wires have taken many forms, and now U.S. researchers have accidentally learned how to grow nanotrees.

Article body

University of Wisconsin-Madison Professor Song Jin and graduate student Matthew Bierman accidentally made some pine tree shapes one day and, in doing so, opened a new chapter in nanotechnology.

The scientists subsequently discovered their nanotrees are evidence of an entirely different way of growing nanowires. Until now, most nanowires have been made with metal catalysts, which promote the growth of nanomaterials along one dimension to form long rods. While the branches on Jin's trees also elongate, growth of the trunks is driven by a screw dislocation in their crystal structure.

Dislocations are fundamental to the growth and characteristics of all crystalline materials, Jin said. But this is the first time they've been shown to aid the growth of one-dimensional nanostructures.

We think these findings will motivate a lot of people to do this purposefully, to design dislocation and try to grow nanowires around it, Jin said.

The research that included Albert Lau, Alexander Kvit and Andrew Schmitt appears in the online journal Science Express.

Copyright 2008 by United Press International

source...
http://it.moldova.org

Self-perfection in nanomanufacturing

In the past, random defects caused by particle contamination were the dominant reason for yield loss in the semiconductor industry - defects occur in the patterning process (so-called process defects) when contaminants become lodged in or on the wafer surface. Trying to prevent such fabrication defects, chip manufacturers have spent much effort and money to improve the fabrication process, for instance by installing ultra-clean fabrication facilities. With the semiconductor industry's move to advanced nanometer nodes, and feature sizes approaches the limitation of the fabrication method used, particles are no longer the only problem for chip manufacturers. In a nanoscale feature-size fabrication environment, systematic variations, such as metal width and thickness variations or mask misalignment, are also major contributors to yield loss. Rather than perfecting a nanostructure by improving its original fabrication method, researchers at Princeton University have demonstrated a new method, known as self-perfection by liquefaction (SPEL), which removes nanostructure fabrication defects and improves nanostructures after fabrication.

link: http://www.nanowerk.com/spotlight/spotid=5568.php