Alain Cappy

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Combining scanning gate microscopy (SGM) experiments and simulations, we demonstrate low temperature imaging of the electron probability density |Psi|(2)(x,y) in embedded mesoscopic quantum rings. The tip-induced conductance modulations share the same temperature dependence as the Aharonov-Bohm effect, indicating that they originate from electron wave(More)
We present measurements of the electron phase coherence time tau(varphi) on a wide range of open ballistic quantum dots (QDs) made from InGaAs heterostructures. The observed saturation of tau(varphi) below temperatures 0.5 K<T(onset)<5 K is found to be intrinsic and related to both the size and the openings of the QDs. Combining our results with previous(More)
Detection of subterahertz and terahertz radiation by high electron mobility GaN=AlGaN transistors in the 0.2–2.5 THz frequency range (much higher than the cutoff frequency of the transistors) is reported. Experiments were performed in the temperature range 4–300 K. For the lowest temperatures, a resonant response was observed. The resonances were(More)
A study of pseudomorphic layers properties using a selfconsistent approach is presented. The strain effects are taken into account. Sheet carrier density and capacitance voltage characteristics are related to technological layer parameters. Simple expressions of subband energy well suited for CAD are then deduced. INTRODUCTION For several years the work on(More)
The intrinsic static and dynamic performance of InAlAs/InGaAs double-gate high electron mobility transistors (DG-HEMTs) is studied by means of an ensemble 2D Monte Carlo simulator. Our model allows going deeply into the physical behavior of this novel device in comparison with similar standard HEMTs. Different gate lengths are analyzed in order to check the(More)
As Moore's law reaches its end, traditional computing technology based on the Von Neumann architecture is facing fundamental limits. Among them is poor energy efficiency. This situation motivates the investigation of different processing information paradigms, such as the use of spiking neural networks (SNNs), which also introduce cognitive characteristics.(More)
By using a Monte Carlo simulator the static and dynamic characteristics of a 50 nm gate AlInAs/GaInAs δ−doped HEMTs are investigated. The Monte Carlo model includes some important effects that are indispensable when trying to reproduce the real behaviour of the devices, such as degeneracy, presence of surface charges, T-shape of the gate, presence of(More)
We report on the design, fabrication and characterization of 100nm T-gates In<sub>0.52</sub>Al<sub>0.48</sub>As/In<sub>0.53</sub>Ga<sub>0.47 </sub>As double-gate HEMTs (DG-HEMT) on InP substrate. In comparison with single gate conventional HEMT, maximum oscillation frequency (f<sub>max</sub>) was increased by 30% when the DG-HEMT operate in simple gate(More)