Researchers reveal insights on silicon semiconductors

Jun 23, 2006
7x7 Si (111) reconstruction
7x7 Si (111) reconstruction

"Smaller. Faster. Wildly complex." This could easily be the motto for semiconductors-the materials that, among lots of other advances in electronics, allow cell phones to continuously shrink in size while increasing the number of their mind-boggling functions.

While exceptionally tiny, semiconductors possess the ability to enable a multitude of complex functions, making them an invaluable ingredient in electronics technology. But, while the computer age is in full bloom, knowledge of semiconductor nanostructures is still relatively young; and research seeking to answer essential and sometimes-basic materials questions is occurring at breakneck speed.

As part of this race to understand semiconductors better, a team of researchers from the University of Wisconsin-Madison has revealed valuable information about silicon and it's surface structure. In particular, the researchers, who did much of their work at the Synchrotron Radiation Center, examined the inimitable 7 x 7 surface structure of Si(111), the most stable surface of silicon.

"Surfaces and interfaces dominate in today's silicon devices, since the surface to volume ratio goes up in small structures. These two-dimensional structures are difficult to study, and the SRC work explores an aspect that has remained unexplored on semiconductors so far," says physicist Ingo Barke, who, along with UW-Madison collaborators, published results in a June 2006 issue of Physical Review Letters.

"Our results reveal a very unusual surface band structure, which can be best explained by a mechanism called 'electron-phonon interaction,'" Barke continues. "Phonons are vibrations of the atoms, which are surrounded by electrons. By shaking the surface atoms the orbiting electrons 'feel' these vibrations and change their movement in a characteristic way. Our work connects two intensively studied fields: electron-phonon interaction which causes conventional superconductivity, and semiconductor surfaces which are of great importance for electronic devices and semiconductor technology."

While similar research has been done on metal surfaces, the current study is the first example of such examination on a semiconductor surface. History has shown that these interesting jumps in basic knowledge about materials such as semiconductors can have significant practical impacts down the road-and this is particularly true in the case of silicon, which itself has become so inextricably important in modern society that it is credited with its own "silicon age."

"Electron-phonon interaction itself is of great scientific and practical interest because it is the key mechanism for conventional superconductivity," Barke notes, adding that the ultimate goal lies in the possibility of tailoring materials for a new generation of "designer superconductors."

Source: University of Wisconsin

Explore further: To conduct, or to insulate? That is the question

Related Stories

Focused energy of lasers breaks microscopic adhesion

Jul 02, 2015

Small objects tend to cling to everything. It's why parents dread hosting parties that involve confetti. It's why glitter is fun for crafts—until it finds its way onto everything else you touch.

What is a terrestrial planet?

Jul 02, 2015

In studying our solar system over the course of many centuries, astronomers learned a great deal about the types of planets that exist in our universe. This knowledge has since expanded thanks to the discovery ...

Engineering atoms inside the jet engine

Jun 29, 2015

The Periodic Table may not sound like a list of ingredients but, for a group of materials scientists, it's the starting point for designing the perfect chemical make-up of tomorrow's jet engines.

The discovery of the molecule Si-C-Si in space

Jun 29, 2015

The space between stars is not empty—it contains a vast reservoir of diffuse material with about 5-10% of the total mass of our Milky Way galaxy. Most of the material is gas, but about 1% of this mass (quite ...

Recommended for you

To conduct, or to insulate? That is the question

Jul 02, 2015

A new study has discovered mysterious behaviour of a material that acts like an insulator in certain measurements, but simultaneously acts like a conductor in others. In an insulator, electrons are largely stuck in one place, ...

How oversized atoms could help shrink

Jul 01, 2015

"Lab-on-a-chip" devices – which can carry out several laboratory functions on a single, micro-sized chip – are the result of a quiet scientific revolution over the past few years. For example, they enable ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.