Calculating the responsivity of a resonant-cavity-enhanced Si1−xGex/Si multiple quantum well photodetector

In this paper, the responsivity of a resonant-cavity-enhanced SiGe/Si multiple quantum well photodetector has been theoretically investigated. The present model considers the effects of material parameters of Si1−xGex and recombination of carriers confined by the potential barriers at the heterointerfaces of Si1−xGex/Si quantum wells on the detector responsivity for different Ge-contents (x). The effect of electric field due to applied bias on the emission of confined carriers from quantized subbands has also been included in the analysis. Results show that though high Ge-content is required to enhance the responsivity of the SiGe/Si photodetector for long-haul communication (at 1.3 and 1.55 μm), the confinement of holes at the heterointerfaces may be significant to affect the responsivity adversely. Studies at 1.3 and 1.55 μm also show that the responsivity of the photodetector for a particular Ge-content in the active layer can be increased by suitable choice of well parameters and applied bias.