Surface plasmon enhanced GeSn photodetectors operating at 2 μm

Au-hole array and Au-GeSn grating structures were designed and incorporated in GeSn metal-semiconductor-metal (MSM) photodetectors for enhanced photo detection at 2 mu m. Both plasmonic structures are beneficial for effective optical confinement near the surface due to surface plasmon resonance (SPR), contributing to an enhanced responsivity. The responsivity enhancement for Au hole-array structure is insensitive to the polarization direction, while the enhancement for Au-GeSn grating structure depends on the polarization direction. The responsivity for GeSn photodetector with Au hole-array structure has similar to 50% reinforcement compared with reference photodetector. On the other hand, Au-GeSn grating structure benefits a 3x enhanced responsivity of 0.455 A/W at 1.5V under TM-polarized illumination. The achieved responsivity is among the highest values for GeSn photodetectors operating at 2 mu m. The plasmonic GeSn photodetectors in this work offer an alternative solution for high-efficiency photo detection, manifesting their great potentials as candidates for 2 mu m optical communication and other emerging applications. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

Au-hole array and Au-GeSn grating structures were designed and incorporated in GeSn metal-semiconductor-metal photodetectors for enhanced photo detection at 2 µm. Both plasmonic structures are beneficial for effective optical confinement near the surface due to surface plasmon resonance, contributing to an enhanced responsivity.