Photo detection and modulation from 1,550 to 2,000 nm realized by a GeSn/Ge multiple-quantum-well photodiode on a 300-mm Si substrate

摘要: A GeSn/Ge multiple-quantum-well (MQW) p-i-n photodiode structure was proposed for simultaneously realizing high detectivity photo detection with low dark current and effective optical modulation based on the quantum confined Stark (QCSE) effect. The MQW stacks were grown a 300-mm Ge-buffered Si substrate using reduced pressure chemical vapor deposition (RPCVD). photodiodes varying mesa diameters fabricated characterized. An ultralow density of 16.3 mA/cm2 at -1 V achieved as expected due to threading dislocation (TDD) in pseudomorphic GeSn layer. Owing responsivity 0.307 A/W, specific 1.37×1010 cm·Hz1/2/W accomplished 1,550 nm, which is comparable commercial Ge extended-InGaAs photodetectors. Meanwhile, bias voltage-dependent response investigated from 1,700 2,200 nm. extracted absorption coefficient shows QCSE behavior electric field-dependent exciton peaks 0.688 0.690 eV. ratio 1.81 under -2 2 μm, early promise modulation. frequency calculated theoretically, predicted 3-dB bandwidth diameter 30 μm could reach 12 GHz V.