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Optical data links are the backbone of today’s telecommunication infrastructure. The integration of electronic and optic components on one chip is one of the most attractive routes to further increase the system performance. Here, we present the fabrication of photodetectors based on CVD-grown graphene on silicon photonic waveguides. The devices operate bias-free in the C-band at 1550 nm and show an extrinsic −3 dB bandwidth of 41 GHz. We demonstrate that these detectors work at data rates up to 50 GBit/s with excellent signal integrity.

Two-dimensional (2D) transition metal dichalcogenides (TMDCs) are seen as promising candidates for flexible electronic and optoelectronic devices due to their high tensile strength and favorable optical properties. Molybdenum disulfide (MoS2) is a benchmark material for TMDCs, which has already been studied extensively. Here, we report on highly responsive flexible few-layer MoS2 photodetectors based on MoS2 synthesized uniformly for full coverage of 2 in. sapphire wafers using metalorganic vapor-phase epitaxy (MOVPE). Device performance is studied by electro-optical characterization. Electrostatic gating allows tuning both the responsivity between 150 and 920 A/W and the specific detectivity between almost 1012 and 1010 Jones. The measured spectrally resolved responsivities of the detectors suggest applications in the blue-light range, with opportunities for fine-tuning the most sensitive wavelength through gating, as shown through optical simulations. Finally, the flexible devices were bent to demonstrate their suitability for flexible electronics in fields of future Internet of Things and medical devices.

We present a graphene photodetector for telecom applications based on a silicon photonic crystal defect waveguide. The photonic structure is used to confine the propagating light in a narrow region in the graphene layer to enhance light-matter interaction. Additionally, it is utilized as split-gate electrode to create a pn-junction in the vicinity of the optical absorption region. The photonic crystal defect waveguide allows for optimal photo-thermoelectric conversion of the occurring temperature profile in graphene into a photovoltage due to additional silicon slabs on both sides of the waveguide, enhancing the device response as compared to a conventional slot waveguide design. A photoresponsivity of 4.7 V/W and a (setup-limited) electrical bandwidth of 18 GHz are achieved. Under a moderate bias of 0.4 V we obtain a photoconductive responsivity of 0.17 A/W., Comment: 13 pages, 4 figures