Highly Efficient Near-Infrared Detector Based on Optically Resonant Dielectric Nanodisks

• Published in: Nanomaterials (Basel, Switzerland) Vol. 11; no. 2; p. 428
• Main Authors: Masoudian Saadabad, Reza, Pauly, Christian, Herschbach, Norbert, Neshev, Dragomir N, Hattori, Haroldo T, Miroshnichenko, Andrey E
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 08.02.2021; MDPI
• Subjects: bandwidth; Bandwidths; Capacitance; dielectric nanodisks; Dielectrics; Diodes; Disks; Efficiency; Electric fields; Germanium; High speed; I.R. radiation; Infrared detectors; Integrated circuits; Light; Nanoparticles; NIR photodetector; Optical properties; Photometers; Photons; Quantum efficiency; Semiconductors; Simulation; Velocity; Wavelengths; dielectric nanodisks; bandwidth; NIR photodetector
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano11020428

Fast detection of near-infrared (NIR) photons with high responsivity remains a challenge for photodetectors. Germanium (Ge) photodetectors are widely used for near-infrared wavelengths but suffer from a trade-off between the speed of photodetection and quantum efficiency (or responsivity). To realize a high-speed detector with high quantum efficiency, a small-sized photodetector efficiently absorbing light is required. In this paper, we suggest a realization of a dielectric metasurface made of an array of subwavelength germanium PIN photodetectors. Due to the subwavelength size of each pixel, a high-speed photodetector with a bandwidth of 65 GHz has been achieved. At the same time, high quantum efficiency for near-infrared illumination can be obtained by the engineering of optical resonant modes to localize optical energy inside the intrinsic Ge disks. Furthermore, small junction capacitance and the possibility of zero/low bias operation have been shown. Our results show that all-dielectric metasurfaces can improve the performance of photodetectors.