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August 7-11, 2006 - Upcoming Conference: Conference on Quantum Information & Quantum Control II - to be held at Fields Institute. Nanotechnology Centre's Director, Prof. Harry Ruda, joins Director of Centre for Quantum Information & Quantum Control (CQIQC), Prof. Aephraim M. Steinberg, on organizing committee for UofT's second international conference on quantum information and quantum control - both "hot topics with promising, yet mostly unexplored overlap ..." (CQIQC)

April 19, 2006 - Prof. Ted Sargent's team creates paint-on laser that could rescue computer chip industry from "interconnect bottleneck" (News@UofT)

November 15, 2005 - "Engineering professor named to Scientific American 50: Nanotechnology researcher recognized for pioneering infrared solar cells". Prof. Ted Sargent has been named to the 2005 Scientific American 50 - an annual list recognizing outstanding leaders in science and technology from the past year (News@UofT)

November 30, 2004 - CAN co-collaborator, Prof. Geoffrey Ozin, together with Prof. Sajeev John, wins first-ever NSERC Brockhouse Canada Prize for creating first photonic crystal capable of trapping light with potential future application in optical computer (News@UofT)

September 19, 2003 - MIT Technology Review names Prof. Edward Sargent as one of World's Top 100 Young Researchers (CITO News)

January 15, 2002 - Prof. Zhenghong Lu Develops Silicon Quantum Well

Atom-thin silicon films for supercomputers

Atom-thin silicon films for supercomputers

From the Science & Technology Desk
Published 1/15/2002 5:09 PM
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TORONTO, Jan. 15 (UPI) -- Atomically thin layers of crystalline silicon called "quantum wells" may help lead to hand-held supercomputers and a light-speed fast Internet in future, scientists in Toronto say.

"This promises to help take silicon to new applications beyond its current limitations, pushing existing transistor technology to new possibilities for microelectronics," said lead researcher Zhenghong Lu at the University of Toronto.

A quantum well is made of sandwiched layers of electrically insulating material and semiconductive films, each only a few nanometers -- billionths of a meter -- thick. The electrons packed together in the atomically thin semiconductor layers remain confined by the insulating nanofilms, forcing the electrons to increase each other's energy levels and emit bright light.

Quantum wells can therefore prove invaluable in light-based electronics. Scientists predict these simple devices will prove key components of many futuristic inventions, such as microchips and computer networks that use lasers and optical fibers to transmit data instead of electrical pulses and metal wires.

Growing the ultrathin silicon-based quantum wells has proven very difficult. Quantum wells need their semiconductive layers to be atomically wide -- only 3 nanometers or less, a width more than 30,000 times thinner than a human hair.

Instead of growing thin layers up from scratch, the scientists instead tried whittling thicker layers down. The researchers grew crystalline, semiconductive layers of pure silicon roughly 50 nanometers thick on 200 nanometer-wide wafers of silicon dioxide, the same insulating material comprising sand. They then exposed the silicon crystal film to ultraviolet light and ozone, which oxidizes the uppermost 2-atom-thick layer. The oxidized silicon was then stripped off by dipping it in hydrofluoric acid.

By repeating this process, they whittled the crystalline silicon down to a half-nanometer, only 2 or 3 atoms wide. What makes the silicon-based quantum wells especially invaluable is the quality of light they emit.

"They emit infrared light at wavelengths of 1.5 microns -- the wavelengths used in telecommunications," Lu said in an interview with United Press International. "No other quantum well system can do that."

Since the quantum wells are so thin, scientists also hope they can exploit the quantum properties matter displays on the atomic level to develop ultrafast transistors.

"When talking about nanoelectronics, you can in theory get really fast, ultrafast computers -- handheld supercomputers," Lu said.

While it might take anywhere from two to 10 years before practical benefits from the silicon quantum wells became available, "this is a very good first step," said solid state physicist David Miller of Stanford University in California, a leading expert in photonics.

Lu and his colleagues are currently working on expanding their quantum well.

"We've just demonstrated one quantum well so far -- stacking of multiple quantum wells, which many devices may require, really will be the next challenge," Lu said.

The researchers reported their results in Applied Physics Letters.

(Reported by Charles Choi in New York.)

Copyright 2001-2003 United Press International
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November 28, 2001 - CAN Researcher wins MRS Silver Medal

Arief Budiman, Ph.D. candidate in the U of T Department of Materials Science and Engineering, received the Graduate Student Silver Award at the 2001 Materials Research Society Fall Meeting (Boston, MA, November 26-30) for his paper entitled "Morphologies of Self-Assembled Quantum Dots - A Variational Approach", co-authored by Professor Harry E. Ruda. The Society presented awards to graduate students who authored or co-authored symposium papers which exemplified significant and timely research.

June 21, 2001 - CAP-GSI Lumonics Best Paper Award goes to CAN Researcher

Arief Budiman, Ph.D. candidate in the U of T Department of Materials Science and Engineering, is this year's first-prize winner of the CAP-GSI Lumonics Award at the CAP 2001 Congress (Victoria, B.C., June 17-21) for his paper entitled "Equilibrium Theory of Coherent Quantum Dot Formation", co-authored by Professor Harry E. Ruda. Through the generosity of GSI-Lumonics Inc., this Award is presented annually at the Congress of the Canadian Association of Physicists in recognition of the best student research paper presented at the Congress. GSI Lumonics is a global company that makes laser systems for the automotive, semiconductor, telecommunications and electronics industries.

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