Presentation Information
[9a-PA1-15]Study on the microscopic loss mechanism of “Absorption-Responsivity Mismatch” in Si/Ge core-shell array resonators
Guanghui Wang1,2, 〇Wipakorn Jevasuwan2, Naoki Fukata1,2 (1.Univ. Tuskuba, 2.NIMS)
Keywords:
core-shell nanowire,nanoresonator,photodetector
Si/Ge core-shell nanoresonators are considered a vital architecture for future Si-based short-wave infrared (SWIR) photodetection technologies to break beyond “More than Moore” limitations. However, merely constructing a resonator structure often means that even if the device absorbs a significant amount of light, the energy dissipates through radiative leakage and fails to efficiently generate carriers. We refer to this issue as the "Absorption-Responsivity mismatch." To address this challenge, we propose a “geometric loss engineering” strategy. We systematically evolved the cross-section of the nanoresonators from polygons (e.g., triangles and squares) to circles. We discovered that, when controlling for equivalent absorption capacity, circular geometries effectively suppress radiative losses and force optical energy directly into active Mie resonance modes within the material. Consequently, our circular Si/Ge arrays achieved a peak responsivity of 8.5 A/W at 1100 nm. This work confirms that achieving high performance relies not solely on total light absorption, but on the effective spatial localization of the optical field within the nanoresonators.