Response-Enhanced GeSn Photodetectors Realized by Photon Trapping Holes Array

Silicon-based GeSn short wave infrared (SWIR) photodetectors (PDs) were designed and fabricated, whose optical response at 2000 nm was enhanced by a carefully designed hole array photon-trapping structure. The photon-trapping structure can change the light propagation direction from being perpendicular to the PD surface to lateral directions, and the absorption efficiency is improved by optical resonance enhancement effect. The responsivity of the GeSn PD with holes array on the surface was measured to be 79.0 mA/W, which has achieved a 2.3 times enhancement at a wavelength of 2000 nm. The high-performance GeSn PDs with photon-trapping structure have offered an alternative solution for high-efficiency silicon-based SWIR detection, manifesting great potential as candidates for extended optical communication and monolithic infrared imaging focal-plane array (FPA).