Orders-of-magnitude Enhanced Performance of THz LTG-GaAs Photomixer Detectors Utilizing Transparent Graphene Finger Electrodes

Dr. Alaa Jabbar Jumaah1, Mr. Jakob Holstein2, Prof. Hartmut G. Roskos2, Prof. Shihab Al-Daffaie1
1Department of Electrical Engineering, Eindhoven University of Technology, 5612 AE Eindhoven, Netherlands. 2Physikalisches Institut, Goethe Universit├Ąt, 60438 Frankfurt am Main, Germany


A novel detector for the detection of terahertz (THz) radiation has been developed using a multilayer of graphene on low temperature grown (LTG) GaAs. This detector outperforms conventional detectors with metallic contacts. Sensitivity, dynamic range and bandwidth are significantly improved. The resulting sensitivity and dynamic range are approximately 30 times greater and the bandwidth is doubled. The transparency of the graphene electrodes, which allows visible and near-infrared light to pass through, is the key to this improvement. This allows the LTG-GaAs material to excite mobile carriers not only between the electrode fingers, but also below them. The enhanced photocurrent measured in this setup is supported by mathematical models and simulations that explain how the enhancement occurs