Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Technology holds promise for infrared camera

Abstract:
Technology has the potential for broad application in the detection of terrorist activities

Technology holds promise for infrared camera

August 11, 2005

New technology developed at Northwestern University has the potential for broad application in the detection of terrorist activities such as missile attacks on U.S. troops. Scientists at the Center for Quantum Devices (CQD) have demonstrated, for the first time, uncooled infrared imaging using type-II superlattice technology. This significant development could lead to smaller, faster and less expensive hand-held infrared imaging devices.

High-speed infrared (IR) imagers are capable of sensing thermal profiles of missiles and other objects that emit heat above that of the background. These devices also have potential in medical applications where excessive heating or cooling in the body can indicate trouble, such as inflammation, circulation issues or even cancerous tissue.

Manijeh Razeghi

CQD Director Dr. Manijeh Razeghi
“For most practical applications, high-speed operation with handheld portability is especially important,” said CQD director Manijeh Razeghi, who led the research team. “Uncooled imagers are capable of handheld operation, which is critical in situations with soldiers on the battlefield or with firefighters in a smoke-filled environment. Cooled sensors, on the other hand, typically utilize liquid nitrogen for cooling to minus 200 degrees Celsius, making the sensors expensive and bulky.”

Type-II superlattices were first proposed by Nobel laureate Leo Esaki in 1973 and were then proposed for use in infrared detection in 1977. It wasn’t until semiconductor epitaxial growth techniques such as molecular beam epitaxy were sufficiently advanced in the 1990s, however, that high-performance infrared photon detection was fully demonstrated.

Currently, silicon microbolometer sensors, which operate on a thermal response principle -- as opposed to photonic response -- are capable of operating at room temperature but are orders of magnitude slower than photon detectors. Photon detectors detect light at infrared wavelengths and convert it directly to an electrical signal, whereas thermal detectors are physically heated by the infrared signal, which changes the resistance of the detector element creating a varying electrical signal, and is a much slower process. Thus type-II superlattices, which are photon detectors, are far more suitable for many applications requiring high-speed operation, such as missile detection.

With a strong program in photonic III-V material growth, device fabrication and development, CQD researchers were the first to demonstrate an imaging type-II superlattice focal plane array, and were also the first to demonstrate uncooled photo detection using type-II superlattice structures.

Recently CQD researchers have demonstrated an uncooled 256 by 256 pixel camera using an InAs/GaSb type-II superlattice, which can detect variations in temperature on the surface of a hot soldering iron while operating at room temperature (with a cutoff wavelength of 5 microns).

“The type-II superlattice will become the next generation infrared material replacing mercury cadmium telluride, or MCT,” said Razeghi, who is Walter P. Murphy Professor of Electrical and Computer Engineering. “MCT has many limitations, especially in the longer wavelength infrared range critical for missile detection, and we have demonstrated type-II detectors from three all the way up to 32 microns.”

Razeghi’s research group has been in very active pursuit of uncooled infrared photon detection. In their work, the researchers fabricated the focal plane arrays using the superlattice materials grown with an Intevac Mod Gen II solid-source molecular beam epitaxy system. At room temperature, the detectivity (the unit of measure to compare detector performance) was around 109 cm·Hz1/2/W.

The work performed at CQD has generated much interest in type-II superlattice research and has brought funding from the U.S. Missile Defense Agency, U.S. Air Force Research Laboratory, Office of Naval Research and Defense Advanced Research Projects Agency, as well as collaborations with Rockwell Scientific Company, Naval Research Laboratory, Jet Propulsion Laboratory and Raytheon Company.

(Source contact: Manijeh Razeghi at 847-491-7251 or razeghi@ece.northwestern.edu)

####


(Ed.'s Note: I asked Megan Fellman to help me out with an explanation as to how this technology fit in the "nano-enabled" category. Megan put me in touch with Professor Razeghi, who in turn provided the following explanation:

"The super lattices use an atomic engineering technique. Atomic layers are deposited one after the other, each layer only a few nanometers thick. The camera has a total of 65,536 pixels, with each pixel connected to a transistor on the read-out integrated circuit (ROIC). The goal is to make individual pixels as small as possible and the format as large as possible. This would lead to higher resolution and a larger imaging field. Groups of nano-meter dimensional pixels would also enable the detector to work at even higher temperatures. The camera is actually an artificial eye, mimicking nature, and can see infrared light."

For those of you who would like to learn more, she explains it further in the introduction to her text book Fundamental of Solid State Engineering.)

Media Contact:
Megan Fellman
(847) 491-3115
fellman@northwestern.edu

Copyright © Northwestern University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

Possible Futures

Cryo-electron microscopy achieves unprecedented resolution using new computational methods March 25th, 2017

Argon is not the 'dope' for metallic hydrogen March 24th, 2017

Promising results obtained with a new electrocatalyst that reduces the need for platinum: Researchers from Aalto University have succeeded in manufacturing electrocatalysts used for storing electric energy with one-hundredth of the amount of platinum that is usually needed March 24th, 2017

Rice U. refines filters for greener natural gas: New study defines best materials for carbon capture, methane selectivity March 23rd, 2017

Sensors

UC researchers use gold coating to control luminescence of nanowires: University of Cincinnati physicists manipulate nanowire semiconductors in pursuit of making electronics smaller, faster and cheaper March 17th, 2017

Optical fingerprint can reveal pollutants in the air: Researchers at Chalmers University of Technology have proposed a new, sophisticated method of detecting molecules with sensors based on ultra-thin nanomaterials March 15th, 2017

New optical nanosensor improves brain mapping accuracy, opens way for more applications: Potassium-sensitive fluorescence-imaging method shines light on chemical activity within the brain March 3rd, 2017

Smart multi-layered magnetic material acts as an electric switch: New study reveals characteristic of islands of magnetic metals between vacuum gaps, displaying tunnelling electric current March 1st, 2017

Announcements

Cryo-electron microscopy achieves unprecedented resolution using new computational methods March 25th, 2017

Argon is not the 'dope' for metallic hydrogen March 24th, 2017

Promising results obtained with a new electrocatalyst that reduces the need for platinum: Researchers from Aalto University have succeeded in manufacturing electrocatalysts used for storing electric energy with one-hundredth of the amount of platinum that is usually needed March 24th, 2017

Artificial photosynthesis steps into the light: Rice University lab turns transition metals into practical catalyst for solar, other applications March 23rd, 2017

Homeland Security

Nanosensors on the alert for terrorist threats: Scientists interested in the prospects of gas sensors based on binary metal oxide nanocomposites November 5th, 2016

Nanobionic spinach plants can detect explosives: After sensing dangerous chemicals, the carbon-nanotube-enhanced plants send an alert November 2nd, 2016

Notre Dame researchers find transition point in semiconductor nanomaterials September 6th, 2016

Down to the wire: ONR researchers and new bacteria August 18th, 2016

Military

Graphene sheets capture cells efficiently: New method could enable pinpoint diagnostics on individual blood cells March 3rd, 2017

Bioinspired process makes materials light, robust, programmable at nano- to macro-scale: Ultralight web of silk nano fibers withstands load 4,000 times its weight February 28th, 2017

'Lossless' metamaterial could boost efficiency of lasers and other light-based devices February 20th, 2017

Engineers shrink microscope to dime-sized device February 17th, 2017

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project