High-Efficiency Photo Detection at 2 μm Realized by GeSn/Ge Multiple-Quantum-Well Photodetectors with Photon-Trapping Microstructure

Photon-trapping microstructure was designed and incorporated into GeSn/Ge multiple-quantum-well photodetectors to enhance the optical absorption. A four times higher responsivity of 0.11 A/W was achieved at a wavelength of 2 μm.