CMOS-compatible graphene photodetector covering all optical communication bands

Optical interconnects are becoming attractive alternatives to electrical wiring in intra- and interchip communication links. Particularly, the integration with silicon complementary metal-oxide semiconductor (CMOS) technology has received considerable interest because of the ability of cost-effective integration of electronics and optics on a single chip(1). Although silicon enables the realization of optical waveguides(2) and passive components(3), the integration of another, optically absorbing, material is required for photodetection. Traditionally, germanium(4) or compound semiconductors(5) are used for this purpose; however, their integration with silicon technology faces major challenges. Recently, graphene(6) emerged as a viable alternative for optoelectronic applications(7), including photodetection(8). Here, we demonstrate an ultra-wideband CMOS-compatible photodetector based on graphene. We achieved a multigigahertz operation over all fibre-optic telecommunication bands beyond the wavelength range of strained germanium photodetectors(9), the responsivity of which is limited by their bandgap. Our work complements the recent demonstration of a CMOS-integrated graphene electro-optical modulator(10), and paves the way for carbon-based optical interconnects.