Subscribe free to our newsletters via your
. 24/7 Space News .


Subscribe free to our newsletters via your




















Silicon-Based Photodetector Is Sensitive To Ultraviolet Light

As will be reported in the August issue of the journal Photonics Technology Letters, the technique behind silicon sensing of ultraviolet light is compatible with conventional integrated circuit technology. Conveniently, both the sensor and the computer could be incorporated on the same chip.
Champaign IL (SPX) Jul 20, 2004
By depositing thin films of silicon nanoparticles on silicon substrates, researchers at the University of Illinois at Urbana-Champaign have fabricated a photodetector sensitive to ultraviolet light. Silicon-based ultraviolet sensors could prove very handy in military, security and commercial applications.

"Silicon is the most common semiconductor, but it has not been useful for detecting ultraviolet light until now," said Munir Nayfeh, a professor of physics at Illinois and a researcher at the Beckman Institute for Advanced Science and Technology.

"Ultraviolet light is usually absorbed by silicon and converted into heat, but we found a way to make silicon devices that absorb ultraviolet light and produce electrical current instead."

As will be reported in the August issue of the journal Photonics Technology Letters, the technique behind silicon sensing of ultraviolet light is compatible with conventional integrated circuit technology. Conveniently, both the sensor and the computer could be incorporated on the same chip.

To create their ultraviolet-based photodetectors, Nayfeh, graduate students Satish Rao, Adam Smith and Joel Therrien, and undergraduate student Osama Nayfeh begin with nanoparticles dispensed from silicon wafers using electrochemical etching. The nanoparticles are about 1 billionth of a meter in diameter and contain about 30 silicon atoms.

The researchers then deposit a thin film of the nanoparticles in a hole etched into the surface of another silicon wafer using standard lithographic techniques. Small conductive pads of gold complete the assembly. Electricity flows when ultraviolet light strikes the nanoparticles.

"Ultraviolet light efficiently couples to the nanoparticles and produces electron-hole pairs," said Nayfeh, who also is a researcher at the university's Center for Nanoscale Science and Technology.

"Contrary to what occurs in bulk silicon, the electron-hole pairs do not appreciably recombine by non-radiative processes. Strong quantum confinement allows for charge separation and collection."

Combining silicon nanoparticles with conventional silicon wafers could offer the best of both material systems, Nayfeh said. "Placing a thin layer of nanoparticles on the front of a silicon solar cell, for example, could improve the cell's efficiency and its lifetime."

Other applications include ultraviolet-based detectors for missile-warning systems and airborne biological agents, industrial flame sensors and suntan monitors.

Related Links
Beckman Institute for Advanced Science and Technology
SpaceDaily
Search SpaceDaily
Subscribe To SpaceDaily Express

STMicroelectronics Advances Non-Volatile Memory Technology
Geneva (SPX) Jul 08, 2004
STMicroelectronics, one of the world's leading semiconductor suppliers, has announced significant progress in the development of a new type of electronic memory that could eventually replace the Flash memory technology.







Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News








The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.