C. Conséjo

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The quantum Hall effect provides a universal standard for electrical resistance that is theoretically based on only the Planck constant h and the electron charge e. Currently, this standard is implemented in GaAs/AlGaAs, but graphene's electronic properties have given hope for a more practical device. Here, we demonstrate that the experimental conditions(More)
Replacing GaAs by graphene to realize more practical quantum Hall resistance standards (QHRS), accurate to within 10(-9) in relative value, but operating at lower magnetic fields than 10 T, is an ongoing goal in metrology. To date, the required accuracy has been reported, only few times, in graphene grown on SiC by Si sublimation, under higher magnetic(More)
Using high-temperature annealing conditions with a graphite cap covering the C-face of, both, on axis and 8° off-axis 4H-SiC samples, large and homogeneous single epitaxial graphene layers have been grown. Raman spectroscopy shows evidence of the almost free-standing character of these monolayer graphene sheets, which was confirmed by magneto-transport(More)
By reassembling thin isolated atomic planes of hexagonal borum nitride (hBN) with a few layer phosphorene black phosphorus (BP), hBN/BP/hBN heterostructures are mechanically stacked to devise high-efficiency THz photodetectors operating in the 0.3-0.65 THz range, from 4 K to 300 K, with a record signal-to-noise ratio of 20 000.
Diffractive optical elements such as hyperbolic lens and quasi-spherical lens converting a divergent terahertz beam into the focal line segment perpendicular to the optical axis was designed. Due to the fact that the length of the line segment was longer than the aperture of the designed elements the nonparaxial approach was used. The structures were(More)
We report on room-temperature detection of subterahertz radiation by InP double heterojunction bipolar transistors designed for 100 Gbit/s circuit applications. Maximum responsivity of 250 V/W around 272 GHz were achieved at room-temperature under unbiased base-emitter and base-collector conditions. We show also that these detectors can operate as sensitive(More)
In the scope of a possible redefinition in the SI, the LNE has decided to develop a new Thompson Lampard calculable capacitor to decrease its uncertainty on the value of von Klitzing constant, RK, to a level of one part in 10. This paper gives an overview of the French experiment. The main characteristics of the new French standard are detailed. The(More)
We report on the stability of the quantum Hall plateau in wide Hall bars made from a chemically gated graphene film grown on SiC. The ν=2 quantized plateau appears from fields B≃5  T and persists up to B≃80  T. At high current density, in the breakdown regime, the longitudinal resistance oscillates with a 1/B periodicity and an anomalous phase, which we(More)
It has recently been shown that electronic states in bulk gapless HgCdTe offer another realization of pseudo-relativistic three-dimensional particles in condensed matter systems. These single valley relativistic states, massless Kane fermions, cannot be described by any other relativistic particles. Furthermore, the HgCdTe band structure can be continuously(More)
A graphene ballistic rectifier is used in conjunction with an antenna to demonstrate a rectenna as a terahertz (THz) detector. A small-area (<1 μm2) local gate is used to adjust the Fermi level in the device to optimize the output while minimizing the impact on the cutoff frequency. The device operates in both n- and p-type transport regimes and shows a(More)