Waveguide-integrated telecom-wavelength photodiode in deposited silicon

Abstract

We demonstrate photodiodes in deposited polycrystalline silicon at $1550\mathrm{nm}$ wavelength with $0.15\mathrm{A}/\mathrm{W}$ responsivity, $40\mathrm{nA}$ dark current, and gigahertz time response. Subband absorption is mediated by defects that are naturally present in the polycrystalline material structure. The material exhibits a moderate absorption coefficient of $6\mathrm{dB}/\mathrm{cm}$, which allows the same microring resonator device to act as both a demultiplexing filter and a photodetector. We discuss the use of deposited silicon-based complementary metal-oxide semiconductor materials for nanophotonic interconnects.

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