Home > Press > Technology holds promise for infrared camera
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.
“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 firstname.lastname@example.org)
(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
Copyright © Northwestern University
If you have a comment, please Contact
Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
Nanocarriers may carry new hope for brain cancer therapy: Berkeley Lab researchers develop nanoparticles that can carry therapeutics across the brain blood barrier November 22nd, 2015
Quantum Spin Could Create Unstoppable, One-Dimensional Electron Waves: New theory points the way forward to transform atom-thin materials into powerful conductors November 18th, 2015
Pioneering research boosts graphene revolution November 17th, 2015
Rice makes light-driven nanosubmarines: Speedy single-molecule submersibles are a first November 16th, 2015
Nanotech-based sensor developed to measure microRNAs in blood, speed cancer detection November 19th, 2015
A simple, rapid test to help ensure safer meat November 19th, 2015
Plasma Focus Device Applied to Produce Zinc Oxide Nanofilms November 18th, 2015
Researchers design and patent graphene biosensors: The Moscow Institute of Physics and Technology is patenting biosensor chips based on graphene, graphene oxide and carbon nanotubes that will improve the analysis of biochemical reactions and accelerate the development of novel dr November 16th, 2015
Physicists explain the unusual behavior of strongly disordered superconductors: Using a theory they developed previously, the scientists have linked superconducting carrier density with the quantum properties of a substance November 25th, 2015
Scientists 'see' detailed make-up of deadly toxin for the first time: Exciting advance provides hope for developing novel potential method of treating pneumococcal diseases such as bacterial pneumonia, meningitis and septicaemia November 25th, 2015
Researchers find new, inexpensive way to clean water from oil sands production November 24th, 2015
Production of Nanocapsules Containing Omega-3 Powder in Iran November 24th, 2015
Nanoparticle delivery maximizes drug defense against bioterrorism agent: UCLA team develops method for improving drug’s efficacy while reducing side effects November 6th, 2015
Toward clearer, cheaper imaging of ultrafast phenomena: A new, all-optical method for compressing narrow electron pulses to a billionth of a billionth of a second could improve real-time movies of chemical reactions and other ultrafast processes October 14th, 2015
Nanopaper as an optical sensing platform July 23rd, 2015
Iranian Scientists Design Nano Device to Detect Cyanogen Toxic Gas June 23rd, 2015
UMD & Army researchers discover salty solution to better, safer batteries: Greatest potential uses seen in safety-critical, automotive and grid-storage applications November 21st, 2015
Navy researchers recruit luminescent nanoparticles to image brain function November 19th, 2015
NIST team proves 'spooky action at a distance' is really real November 14th, 2015
Nanopores could take the salt out of seawater November 10th, 2015