2-D Material Shows Promise for Image Sensing
HOUSTON, Dec. 22, 2014 — Ultrathin chalcogenide films could form the basis of tiny, adaptable bioimagers.
Composed of copper indium selenide (CIS), a prototype three-pixel CCD has already demonstrated the ability to capture and store image information, according to researchers at Rice University.
Flexible CIS films could be curved to match the focal surface of an imaging lens system, which could allow for the real-time correction of optical aberrations, the researchers said.
Rice University graduate student Sidong Lei synthesized the 2-D CIS image sensor. Courtesy of Jeff Fitlow/Rice University.
“Traditional CCDs are thick and rigid, and it would not make sense to combine them with 2-D elements,” said graduate student Sidong Lei. “CIS-based CCDs would be ultrathin, transparent and flexible and are the missing piece for things like 2-D imaging devices.”
CIS pixels are highly sensitive to light because trapped electrons dissipate slowly, said senior faculty fellow Dr. Robert Vajtai.
“There are many two-dimensional materials that can sense light, but none are as efficient as this material,” he said. “This material is 10 times more efficient than the best we’ve seen before.”
Lei and colleagues extracted 2-nm-thick sheets from synthetic CIS crystals. The material may also be grown via chemical vapor deposition.
A 2-D, three-pixel prototype CIS sensor could be the basis for future flat imaging devices. Courtesy of the Ajayan Group/Rice University.
The researchers also experimented with layers of indium selenide and molybdenum disulfide, another light-detecting chalcogenide.
Funding for the project came from the U.S. Army Research Office Multidisciplinary University Research Initiative, the Function Accelerated nanoMaterial Engineering Division of the Semiconductor Technology Advanced Research Network, the Microelectronics Advanced Research Association, DARPA, the Netherlands Organization for Scientific Research, the Robert A. Welch Foundation, the National Security Science and Engineering Faculty Fellowship and the Office of Naval Research.
The research was published in Nano Letters (doi: 10.1021/nl503505f).
For more information, visit www.rice.edu.
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