Ref HAL: hal-01101034_v1
DOI: 10.1063/1.4903473
WoS: 000346266000012
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14 Citations
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We report on the demonstration of Terahertz (THz) broadband detectors based on field effect transistors exploiting tapered semiconductor nanowires. The intrinsic asymmetry provided by the nanowires geometry allows to achieve responsivity values as high as 55 V/W (2.5 mA/W) and a noise-equivalent-power of 3 × 10−10 W/Hz1/2 independent of the specific gate voltage applied. The possibility to reduce the number of terminals required to the source and drain contacts only and the technological feasibility of multi-pixel arrays are promising for the realization of compact and integrated THz matrix array detection systems.

Ref HAL: hal-01056398_v1
DOI: 10.1117/12.2040529
WoS: 000337347500018
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2 Citations
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We report on the development of a novel class of nanowire-based THz detectors in which the field effect transistor (FET) is integrated in a narrow-band antenna. When the THz field is applied between the gate and the source terminals of the FET, a constant source-to-drain photovoltage appears as a result of the non-linear transfer characteristic of the transistor. In order to achieve attoFarad-order capacitance we fabricate lateral gate FET with gate widths smaller than 100 nm. Our devices show a maximum responsivity of 110 V/W without amplification, with noise equivalent power levels <= 1 nW/root Hz at room temperature. The 0.3 THz resonant antenna has bandwidth of similar to 10 GHz and opens a path to novel applications of our technology including metrology, spectroscopy, homeland security, biomedical and pharmaceutical applications. Moreover the possibility to extend this approach to relatively large multi-pixel arrays coupled with THz sources makes it highly appealing for a future generation of THz detectors.

Ref HAL: hal-01018293_v1
DOI: 10.1063/1.4885499
WoS: 000338515900014
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95 Citations
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We report on room-temperature plasmonic detection of sub-terahertz radiation by InAlAs/InGaAs/InP high electron mobility transistors with an asymmetric dual-grating-gate structure. Maximum responsivities of 22.7 kV/W at 200 GHz and 21.5 kV/W at 292 GHz were achieved under unbiased drain-to-source condition. The minimum noise equivalent power was estimated to be 0.48 pW/Hz0.5 at 200 GHz at room temperature, which is the record-breaking value ever reported for plasmonic THz detectors. Frequency dependence of the responsivity in the frequency range of 0.2-2 THz is in good agreement with the theory.

Ref HAL: hal-00981498_v1
DOI: 10.1364/OE.22.008996
WoS: 000335902200017
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16 Citations
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We report on the development of an innovative class of nanowire-based Terahertz (THz) detectors in which the metamaterial properties of an antenna have been imported in the detection scheme of an overdamped plasma-wave field-effect transistor making its response resonant to THz radiation. Responsivities of ~105 V/W at 0.3THz, with noise equivalent power levels ≈10−10W/√Hz, detectivities ~2*108cm√Hz/W and quantum efficiencies ~1.2*10−5 are reached at room-temperature. The resonant nature of the detection scheme provided by the four-leaf-clover-shaped geometry and the possibility to extend this technology to large multi-pixel arrays opens the path to demanding applications for ultra-sensitive metrology, spectroscopy and biomedicine.

Ref HAL: hal-00973456_v1
Ref Arxiv: 1310.0969
DOI: 10.1038/nphys2857
WoS: 000332185900021
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176 Citations
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Solid-state physics and quantum electrodynamics, with its ultrarelativistic (massless) particles, meet in the electronic properties of one-dimensional carbon nanotubes, two-dimensional graphene or topological-insulator surfaces. However, clear experimental evidence for electronic states with a conical dispersion relation in all three dimensions, conceivable for certain bulk materials, is still missing. Here, we study a zinc-blende crystal, HgCdTe, at the point of the semiconductor-to-semimetal topological transition. For this compound, we observe three-dimensional massless electrons, as certified from the dynamical conductivity increasing linearly with the photon frequency, with a velocity of about 106 m s−1. Applying a magnetic field B results in a -dependence of dipole-active inter-Landau-level resonances and spin splitting of Landau levels also following a -dependence--well-established signatures of ultrarelativistic particles but until now not observed experimentally in any solid-state electronic system.

Commentaires: http://arxiv.org/abs/1310.0969 The authors acknowledge helpful discussions with T. Brauner, R. Grill, M. Grynberg, A. A. Nersesyan, V. Novák, M. L. Sadowski and W. Zawadzki. The work has been supported by the ERC project MOMB, by EuroMagNET II under the EU Contract No. 228043, by the GDR-I project 'Semiconductor sources and detectors of THz frequencies' and by the Scientific Council of Montpellier II University. We also acknowledge the support received from the Ambassade de France en Russie for the French-Russian collaboration and exchange of PhD students.

Ref HAL: hal-00960242_v1
Ref Arxiv: 1312.3737
DOI: 10.1063/1.4864082
WoS: 000331803800011
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149 Citations
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We report bilayer-graphene field effect transistors operating as Terahertz (THz) broadband photodetectors based on plasma-waves excitation. By employing wide-gate geometries or buried gate configurations, we achieve a responsivity ∼1.2 V/W (1.3 mA/W) and a noise equivalent power ∼2 × 10−9 W/√Hz in the 0.29-0.38 THz range, in photovoltage and photocurrent mode. The potential of this technology for scalability to higher frequencies and the development of flexible devices makes our approach competitive for a future generation of THz detection systems.

Ref HAL: hal-00954475_v1
DOI: 10.1049/el.2013.3702
WoS: 000331405200051
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20 Citations
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The detection of high data-rate wireless communication using a terahertz- frequency carrier, and a GaAs transistor as a detector, is reported. Communications are investigated around 0.2 and 0.3087 THz. For the first time, an error-free transmission at data rates up to 8.2 Gbit/s is demonstrated, using a carrier frequency of 0.3087 THz.