High-speed van der Waals heterostructure tunneling photodiodes integrated on silicon nitride waveguides

Graphene photodetectors can have broadband operation and a large bandwidth, but they usually suffer from a large dark current when biased. To solve this problem, we demonstrate van der Waals heterostructure tunneling photodiodes integrated on silicon nitride waveguides. The heterostructure is made up of layers of molybdenum disulfide, graphene, boron nitride, and graphene from bottom to top. The bottom graphene is n-doped by molybdenum disulfide while the top graphene layer remains p-doped. Between the two graphene layers, multilayer boron nitride was employed as a tunneling barrier. At similar to 1550 nm, high on/off current ratios larger than 10(4) were measured in the dark. A responsivity of similar to 0.24 A/W and a bandwidth of 28 GHz (56 GHz by deconvolving response of experimental system) were also obtained. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement