Abstract-Graphene vertical hot-electron terahertz detectors

V. Ryzhii^1,2,a), A. Satou¹, T. Otsuji¹, M. Ryzhii³, V. Mitin⁴ and M. S. Shur⁵
http://scitation.aip.org/content/aip/journal/jap/116/11/10.1063/1.4895738
1 Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577, Japan
2 Center for Photonics and Infrared Engineering, Bauman Moscow State Technical University and Institute of Ultra High Frequency Semiconductor Electronics, Russian Academy of Sciences, Moscow 111005, Russia
3 Department of Computer Science and Engineering, University of Aizu, Aizu-Wakamatsu 965-8580, Japan
4 Department of Electrical Engineering, University at Buffalo, Buffalo, New York 1460-1920, USA
5 Departments of Electrical, Electronics, and Systems Engineering and Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
a) Electronic mail: v-ryzhii@riec.tohoku.ac.jp
J. Appl. Phys. 116, 114504 (2014); http://dx.doi.org/10.1063/1.4895738

We propose and analyze the concept of the vertical hot-electron terahertz (THz) graphene-layerdetectors (GLDs) based on the double-GL and multiple-GL structures with the barrier layers made of materials with a moderate conduction band off-set (such as tungsten disulfide and related materials). The operation of these detectors is enabled by the thermionic emissions from the GLs enhanced by the electrons heated by incoming THz radiation. Hence, thesedetectors are the hot-electron bolometric detectors. The electron heating is primarily associated with the intraband absorption (the Drude absorption). In the frame of the developed model, we calculate the responsivity and detectivity as functions of the photon energy, GL doping, and the applied voltage for the GLDs with different number of GLs. The detectors based on the cascade multiple-GL structures can exhibit a substantial photoelectric gain resulting in the elevated responsivity and detectivity. The advantages of the THz detectors under consideration are associated with their high sensitivity to the normal incident radiation and efficient operation at room temperature at the low end of the THz frequency range. Such GLDs with a metal grating, supporting the excitation of plasma oscillations in the GL-structures by the incident THz radiation, can exhibit a strong resonant response at the frequencies of several THz (in the range, where the operation of the conventional detectors based on A3B5 materials, in particular, THz quantum-well detectors, is hindered due to a strong optical phonon radiation absorption in such materials). We also evaluate the characteristics of GLDs in the mid- and far-infrared ranges where the electron heating is due to the interband absorption in GLs.