CMOS-compatible graphene photodetector covering all optical communication bands

Abstract

Optical interconnects are becoming attractive alternatives to electrical wiring in intra- and inter-chip communication links. Particularly, the integration with silicon complementary metal-oxide-semiconductor (CMOS) technology has received considerable interest due to the ability of cost-effective integration of electronics and optics on a single chip. While silicon enables the realization of optical waveguides and passive components, the integration of another, optically absorbing, material is required for photodetection. Germanium or compound semiconductors are traditionally used for this purpose; their integration with silicon technology, however, faces major challenges. Recently, graphene has emerged as a viable alternative for optoelectronic applications, including photodetection. Here, we demonstrate an ultra-wideband CMOS-compatible photodetector based on graphene. We achieve multi-gigahertz operation over all fiber-optic telecommunication bands, beyond the wavelength range of strained germanium photodetectors, whose responsivity is limited by their bandgap. Our work complements the recent demonstration of a CMOS-integrated graphene electro-optical modulator, paving the way for carbon-based optical interconnects.