Development of a Less Toxic, Sensitive IR Detector Using Optical Antennas and Zigzag Wires
—Enhancement of Quantum Well-Generated Electric Current Using Antenna Resonance May Be Applicable to the Development of Sensitive Room-Temperature IR Detectors—
National Institute for Materials Science (NIMS)
NIMS has developed a low-toxicity infrared (IR) detector consisting of an array of optical antennas interconnected by unique zigzag wiring and demonstrated that it is sufficiently sensitive for practical use. This IR detector may replace current high-sensitivity cooled IR detectors—which contain toxic mercury and cadmium—for use in gas analyzers and IR cameras.
(”Synchronously wired infrared antennas for resonant single-quantum-well photodetection up to room temperature” Hideki T. Miyazaki,
Takaaki Mano,
Takeshi Kasaya, Hirotaka Osato, Kazuhiro Watanabe,
Yoshimasa Sugimoto,
Takuya Kawazu, Yukinaga Arai,
Akitsu Shigetou,
Tetsuyuki Ochiai, Yoji Jimba (Nihon Univ.), and Hiroshi Miyazaki (Tohoku Univ.); Journal: Nature Communications [January 28, 2020]; DOI :
10.1038/s41467-020-14426-6)
Abstract
- NIMS has developed a low-toxicity infrared (IR) detector consisting of an array of optical antennas interconnected by unique zigzag wiring and demonstrated that it is sufficiently sensitive for practical use. This IR detector may replace current high-sensitivity cooled IR detectors—which contain toxic mercury and cadmium—for use in gas analyzers and IR cameras.
- A number of gas molecules have unique absorption spectra within the IR range. For this reason, IR radiation plays a vital role in the analysis of atmospheric gases. Mercury cadmium telluride detectors have conventionally been used to measure air pollution gases, such as NOx and SOx, as they are sensitive to the IR wavelength range (5 to 10 μm) relevant to these gases. However, the continued use of toxic mercury and cadmium has become difficult due to the adoption of the Restriction of Hazardous Substances (RoHS) Directive by the European Union and the recently enforced Minamata Convention on Mercury. These movements have inspired the development of sensitive, low-toxicity IR detectors.
- The research team recently developed a novel IR detector by fabricating quantum wells using low-toxicity materials, integrating them into optical antennas and interconnecting the antennas with zigzag wiring. The team then found that the sensitivity of this detector was comparable to that of conventional IR detectors. The new detector is equipped with quantum wells only 4 nm in thickness capable of converting incident IR radiation into electric current. When an optical antenna resonates in response to incident light, it significantly enhances the electric current. However, it was found that the wiring connecting optical antennas designed to extract the generated electric currents disrupts antenna resonance. In this project, the research team succeeded in extracting large electric currents without disrupting the resonance states of any of the antennas by bending the wires into a zigzag pattern, thereby precisely adjusting the timing at which electromagnetic waves travel through the wires.
- The design of this IR detector can be modified in a variety of ways: dimensional changes to the quantum well and optical antenna components would alter the physical properties of the detector. We intend to intensify our development efforts with the goal of creating an ultimate IR detector that is highly sensitive at room temperature. Optical antennas interconnected by zigzag wiring may serve as a fundamental technology in various devices (e.g., IR radiation sources) in addition to IR detectors.
- This project was carried out jointly by a NIMS research team led by Hideki T. Miyazaki (Group Leader, Research Center for Functional Materials (RCFM), NIMS) and Takaaki Mano (Principal Researcher, RCFM, NIMS), Nihon University and Tohoku University. This work was funded by JSPS Grants-in-Aid for Scientific Research (grant numbers 15H02011, 17H01275 and 19H00875) and Iketani Science and Technology Foundation.
- This research was published in the open access journal Nature Communications on January 28, 2020, Japan Time. This research will also be presented orally at the JSAP (Japan Society of Applied Physics) Spring Meeting (scheduled to take place at Sophia University on March 13, 2020).
Figure. (a) Scanning electron micrograph of the newly developed infrared detector. (b) Schematic structural diagram. The semiconductor layer containing the quantum wells is sandwiched between the top and bottom gold layers. (c) Detection sensitivity spectra at various temperatures.
