講演情報
[17a-PA1-9]Relationship between Optical Absorption and Responsivity in Si/Ge Core-Shell Nanoresonators
〇(DC)Guanghui WANG1,2, Wipakorn Jevasuwan2, Naoki Fukata1,2 (1.Univ. of Tsukuba, 2.NIMS)
キーワード：
SWIR photodetector、Si/Ge core-shell nanoresonators
Si/Ge core-shell nanostructures are a key platform for CMOS-compatible SWIR photodetection. However, using nanostructures often leads to a problem we call the “Absorption-Responsivity mismatch.” This means that even if the device absorbs a lot of light, it doesn't always generate efficient carriers because energy is lost through radiative leakage. To solve this, we propose a 'geometric loss engineering' strategy. We systematically evolved the cross-section of our nanoresonators from polygons (like triangles and squares) to circles. We found that circular geometries suppress radiative loss and force optical energy into active Mie resonance modes directly inside the material. Consequently, our circular Si/Ge arrays achieved a peak responsivity of 8.5 A/W at 1100 nm. This work confirms that high performance depends not just on absorption, but on effectively localizing the light field within the nanoresonators.