CMOS-compatible graphene photodetector covering all optical communication bands

Abstract

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 chip1. Although silicon enables the realization of optical waveguides2 and passive components3, the integration of another, optically absorbing, material is required for photodetection. Traditionally, germanium4 or compound semiconductors5 are used for this purpose; however, their integration with silicon technology faces major challenges. Recently, graphene6 emerged as a viable alternative for optoelectronic applications7, including photodetection8. 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 photodetectors9, the responsivity of which is limited by their bandgap. Our work complements the recent demonstration of a CMOS-integrated graphene electro-optical modulator10, and paves the way for carbon-based optical interconnects. A CMOS-compatible photodetector based on graphene with multi-gigahertz operation ranging from the O- to U-band of telecommunication bands is demonstrated, highlighting the promise of graphene as a new material for integrated photonics.