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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)
Metamorphic HEMTs are attractive candidates for microwave and mm-wave low noise and power applications. Using the metamorphic concept, high quality relaxed heterostructures with arbitrary chosen In content can be grown. Metamorphic discrete HEMTs and metamorphic MMICs showing electrical performance similar to InP based devices and circuits have been(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)
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)