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ECE NEWS :The Electrical & Computer Engineering Department Newsletter


FALL/WINTER 2006-2007
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Candid Cameras : Setting up wireless networks for surveillance and beyond

POWER is blowing
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World-record speed
for thin-film transistors could revolutionize flexible electronics

The quick and the quantum: Knezevic applies NSF CAREER award to faster computing

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The quick and the quantum: Knezevic applies NSF CAREER award to faster computing

Irena Knezevic

Irena Knezevic (View larger image)

Decorative initial cap Speed has been one of the driving factors in the semiconductor industry in recent years. Computers and digital devices have progressively become faster. “For the average user, better performance means that you can do everything you want to do faster,” says Assistant Professor Irena Knezevic.

Just how fast will field-effect transistors for computing and other digital electronic applications eventually become? The very newest and tiniest of these voltage-controlled switches can toggle between their on and off states every picosecond, or one trillionth of a second—entering what is called the terahertz range. “The question is, ‘Can you go beyond this?’” says Knezevic. “Because when transistors switch this quickly, they become very hard to characterize.”

One of five College of Engineering faculty to receive a National Science Foundation Faculty Early Career Development Award (CAREER) in 2006, Knezevic will explore this question as she develops new quantum-mechanical theory and simulators capable of describing nanoscale devices operating on ultra-short time scales. The NSF CAREER awards, among the most prestigious given to faculty members who are just beginning their academic careers, are granted to creative projects that integrate research and education effectively.

With her five-year, $400,000 award, Knezevic will address a basic problem in the behavior of electrons, whose flow within transistors controls the “on” and “off” states. In transistors that switch between these states much more slowly than once every picosecond, like those in today’s computers, electrons act as individual entities. Thus, says Knezevic: “You can mathematically describe transistors one electron at a time.”

But when transistors switch at time scales of a picosecond or less, electrons begin displaying strange collective properties. Since they don’t act individually, the familiar math no longer works. “Now, you must treat all the electrons as one system,” she explains, “and that requires some heavy mathematical artillery and changes in the simulation software you use to predict electron behavior.”

Knezevic plans to develop software designed to handle the complex algorithms needed to simulate collective electron phenomena. This project is part of a research trend in ultrafast processes, she says.

The software would foster quantum mechanics understanding that applies not only to transistors, but also to any situation in which a small system communicates with the outside world. “The issues are general issues that occur in quantum information theory as well as device physics,” says Knezevic. “We’ll be developing the theory and the simulators. Notions that come out of it should be useable not only in device simulations but more broadly.”

A major outcome of the proposed research will be a web-based virtual nano-electronics laboratory (VNL), where graduate students will be able to access custom-made software and supporting materials to learn about solid state nanoelectronics and semiconductor transport.

A big advantage of the VNL is the ability to study nanoelectronic devices through simulation without a clean room. “The VNL will literally allow students to play on a computer with nanodevices—to make them, vary their features and see how they behave,” says Knezevic.

With help from the UW-Madison Materials Research Science and Engineering Center, she also plans to create a version of the VNL suitable for high school students.

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Date last modified: Monday,19-Feb-2007 15:43:00 CDT
Date created: 19-Feb-2007



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