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    Integration and characterisation of Schottky diodes with a pre-amplifier for THz applications
    (2020-11-08)
    Hajo, Ahid S.
    ;
    Yilmazoglu, Oktay
    ;
    Kuppers, Franko
    ;
    Kusserow, Thomas
    This contribution deals with the investigation and characterisation of fully integrated broadband Terahertz (THz) Schottky diodes using silver (Ag) metallic nanowires (NWs) with 120 nm diameter as bridge contacts for zero-bias operating THz detectors based on highly doped Gallium Arsenide (GaAs) and Indium Gallium Arsenide (InGaAs) layers. The combination of InGaAs and metallic NWs shows almost 7 times higher forward current than the metallic NW with GaAs at 0.27 V with a capacitance of 0.5 fF and a series resistance of 29Omega. The highest calculated cut-off frequency of 10.7 THz was obtained for a NW contacted vertical InGaAs diode.
    Publicationtype: Conference Paper
      33
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    Highly Transparent Graphene Electrodes for CW THz Applications
    (2020-11-08)
    Jumaah, Alaa Jabbar
    ;
    Al-Daffaie, Shihab
    ;
    Kusserow, Thomas
    ;
    Monroy, Idelfonso Tafur
    Transparent graphene-based electrodes for CW THz devices are intensively investigated here. The multilayer graphene (MLG) electrodes were transferred on top of Low temperature GaAs (LT-GaAs) as photoconductive material. The high transparency of the graphene allows 97% of the light to propagate through the transparent electrodes and increase the effective illuminated area. This will increase the carrier density, which leads to higher generated photocurrent. The simulation predicts more than one order of magnitude higher photocurrent can be reached by using multilayer graphene instead of a metal, such as gold. The benefits of using MLG instead of metal conductor results in a 40 times higher photocurrent than the photocurrent using gold electrodes at 20 V bias voltage.
    Publicationtype: Conference Paper
      43
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    High Performance Graphene-Based CW THz Photoconductive Detector
    (2020-11-08)
    Jumaah, Alaa Jabbar
    ;
    Al-Daffaie, Shihab
    ;
    Kusserow, Thomas
    ;
    Monroy, Idelfonso Tafur
    New CW THz detectors based on graphene nanoelectrodes photomixer are completely investigated. The graphene nanoelectrodes are placed on low-temperature-grown (LTG) GaAs as photoconductive material. Due to the high transparency and high conductivity of graphene, increasing carrier densities were obtained which leads to the high performance detection of THz induced photocurrent being one order of magnitude higher than for conventional metallic interdigitated photomixer. The THz measurement was performed in the range of 50 GHz to 1.1 THz.
    Publicationtype: Conference Paper
      30
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    Item type:Publication, Access status: without files ,
    Fabrication and characterization of high power Gallium Nitride based terahertz Gunn diodes
    (2020-11-08)
    Hajo, Ahid S.
    ;
    Yilmazoglu, Oktay
    ;
    Dadgar, Armin
    ;
    Kuppers, Franko
    ;
    Kusserow, Thomas
    In this paper, we report the fabrication and characterization of a THz Gunn source based on Gallium Nitride (GaN) with side-contact and field-plate technologies. This source works stable at operating voltages up to 20 V due to good passivation layer and good heat sink to the GaN substrate. The GaN-based Gunn diode has relatively high forward current of 0.9 A and a high current drop of about 50 mA for higher frequency and output power.
    Publicationtype: Conference Paper
      37