title: Controlled Generation of a p-n Junction in a Waveguide Integrated Graphene Photodetector.
abstract: With its electrically tunable light absorption and ultrafast photoresponse, graphene is a promising candidate for high-speed chip-integrated photonics. The generation mechanisms of photosignals in graphene photodetectors have been studied extensively in the past years. However, the knowledge about efficient light conversion at graphene p-n junctions has not yet been translated into high-performance devices. Here, we present a graphene photodetector integrated on a silicon slot-waveguide, acting as a dual gate to create a p-n junction in the optical absorption region of the device. While at zero bias the photothermoelectric effect is the dominant conversion process, an additional photoconductive contribution is identified in a biased configuration. Extrinsic responsivities of 35 mA/W, or 3.5 V/W, at zero bias and 76 mA/W at 300 mV bias voltage are achieved. The device exhibits a 3 dB bandwidth of 65 GHz, which is the highest value reported for a graphene-based photodetector.
authors.affiliation: Institute of Photonics, Vienna University of Technology , Gußhausstraße 27-29, 1040 Vienna, Austria.
authors.forename: Simone
authors.initials: S
authors.lastname: Schuler
authors.affiliation: AMO GmbH, Otto-Blumenthal-Straße 25, 52074 Aachen, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Schall
authors.affiliation: AMO GmbH, Otto-Blumenthal-Straße 25, 52074 Aachen, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Neumaier
authors.affiliation: Institute of Photonics, Vienna University of Technology , Gußhausstraße 27-29, 1040 Vienna, Austria.
authors.forename: Lukas
authors.initials: L
authors.lastname: Dobusch
authors.affiliation: Institute of Solid State Electronics, Vienna University of Technology , Floragasse 7, 1040 Vienna, Austria.
authors.forename: Ole
authors.initials: O
authors.lastname: Bethge
authors.affiliation: Institute of Solid State Electronics, Vienna University of Technology , Floragasse 7, 1040 Vienna, Austria.
authors.forename: Benedikt
authors.initials: B
authors.lastname: Schwarz
authors.affiliation: Institute of Photonics, Vienna University of Technology , Gußhausstraße 27-29, 1040 Vienna, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Krall
authors.affiliation: Institute of Photonics, Vienna University of Technology , Gußhausstraße 27-29, 1040 Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Mueller
keywords: Graphene; integrated photonics; photodetector; photothermoelectric effect