講演情報
[10a-P01-24]Hexagonal Array of Silicon-Germanium Alloy Nanodisks for Narrow-band Near Infrared Absorption Enhancement
〇(M2)Nguyen Quoc Chien1, Keisuke Moriasa1, Hiroshi Sugimoto1, Minoru Fujii1 (1.Kobe Univ.)
キーワード：
metasurface、SiGe、Nanodisk
Expanding the detection wavelength range of Si-based photodetectors over 1400 nm is very important to effectively use near-infrared (NIR) light in the eye-safe wavelength range in various applications utilizing free-space light. We have shown that toroidal dipole resonances supported by hexagonal array of polycrystalline Si nanodisks strongly enhance the defect-related sub-bandgap light absorption and the photocurrent caused by the absorption. Therefore, the metasurface may be used for Si-based photodetectors operating in the eye-safe wavelength range. show the calculated absorptance as a function of the extinction coefficient of polycrystalline Si for different resonance modes. The absorptance depends strongly on the extinction coefficient and has the maximum at a specific value. Therefore, tuning the material parameters as well as the structural parameters are indispensable to maximize the absorption enhancement.In this work, in order to control the extinction coefficient in a wide range, we replaced polycrystalline Si to polycrystalline Si1−xGex alloy. In Si1−xGex alloy.