You are browsing the archives of 2008 November.

Students Barbara Terlouw and Robin van der Bles, with teacher JanHendrik Wolters (standing).

Two Dutch high school students have captured the top prize in an annual competition sponsored by PANalytical, a supplier of analytical and X-ray diffraction equipment, to stimulate young people’s interest in science. This year’s prize - a week-long “Expedition to the Greenhouse World” in Spitsbergen, Norway - was awarded to Barbara Terlouw and Robin van der Bles for a short film they wrote and produced entitled, “Space Investigation.” The film portrays the students’ vision of the consequences of climate change. The film and trip were tied into an educational project coordinated with Utrecht University to make high school students more aware of climate and their environment. During the expedition, Terlouw and van der Bles wrote a daily weblog to chart the tour’s progress and their reflections on a trip that took them to the Longyearbyen Glacier, fossil hunting and almost two and a half miles underground to explore a working coal mine, where they saw 55-million year old footprints made by extinct hippopotamus-like mammals. Unless you can read Dutch, you won’t get much out of the blog itself. However, the photographs and video the students posted on the website make for fascinating viewing. The students also took time to thank PANalytical, headquartered in Almelo, the Netherlands, for making the trip possible.

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Why settle for one photon when you can get 200-300? That’s the idea behind a new material being developed by SiOnyx, a new Massachusetts company. The company using a method to reshape the surface of silicon to create cones that it says makes the material effectively function as “sponge for light.” is making a new type of silicon material, dubbed black silicon, which captures nearly all of the sun’s light. The makers also claim that material provides reduced weight.

SiOnyx’s technology was developed and is licensed from Harvard University, also claims that the material makes it possible to use less silicon for light sensors, making the devices cheaper, smaller, and lighter.

Another way to look at the material is that it creates a very light-sensitive detector. Thus, besides PV applications, it could find its way into a number of different applications.

“If you have a very high-sensitivity detector, you could lower the radiation dose of x-rays to get that image,” says Stephen Saylor, company CEO. Saylor also suggests in-vitro imaging, night-vision optics and improved digital cameras.

From MIT’s Technology Review:

“Black silicon extends the technology that we know extremely well and makes it usable in a region of spectrum where it wasn’t useful before,” says Eric Mazur, a professor of applied physics at Harvard, who discovered the material in his lab. “I really believe it’s a new class of materials, just as semiconductors were a new class of materials 60 years ago.”

Mazur’s technique begins with ordinary silicon. Put it in a chamber full of sulfur hexafluoride gas, and pulse it with a femtosecond laser. This roughens the surface by creating millions of tiny cones on it. The rough layer is about 300 nanometers thick and infused with sulfur atoms.

This resulting cone-covered 300 nm thin layer does the trick, compared to the .5-mm used in many other PV applications.

The are still some questions about how exactly the material functions, but a leap in the silicon-sulfur material’s light absorbtion ability/photoconductive gain is where researchers are placing their hunch.

“We believe this is really the first time photonic gain has been seen in silicon,” Saylor says.

SiOnyx has yet to demonstrate a working PV application and acknowledges both technical and fabrication hurdles remain, but remain optimistic.

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Researchers at DOE’s Brookhaven National Lab have developed a sandwich of thin films that, at the point where the films touch, offers a nanometer-sized area of superconductivity. Moreover, as reported in the Oct. 9 edition of Nature magazine, the superconductivity takes place at the relatively high temperature of 50 Kelvin (minus 223.15°C) - a temp the Brookhaven team believes can be tweaked even higher.

“What we have done is, we have put together two materials - neither of which is a superconductor - and we found their interface, where they touch, is superconducting,” announces physicist Ivan Bozovic, the project’s leader, in an Oct. 8 Reuters.com article. “It opens vistas for further progress, including using these techniques to significantly enhance  superconducting properties in other known or new superconductors,” Bozovic continues, explaining the significance of his team’s development.

The hope, of course, is to produce a superconductor that can operate at room temperatures, eliminating the need for expensive cryogens and opening the door to more affordable and practical electrical devices, power grids and - just possibly - solutions to the world’s energy crisis. Bozovic says as much on Brookhaven’s website:

“Further study of the temperature-enhancement mechanism might even tell us something about the big puzzle - the mechanism underlying high-temperature superconductivity, which remains one of the most important open problems in condensed matter.”

He says that now researchers can focus on accomplishing this goal by creating a variety of sandwiches from a broad range of nonsuperconducting materials.

“It is too early to tell what applications this research might yield, but already at this stage we can speculate that this brings us one big step closer to the fabrication of useful three-terminal superconducting devices, such as a superconductive field-effect transistor.”

Brookhaven has filed a U.S. provisional patent application for this work. Interested in licensing information? Contact Kimberly Elcess, 631-344-4151, for details.

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