Related papers: Reducing disorder in Ge quantum wells by using thi…

The geometry of quantum wells (QWs) critically influences carrier mobility, yet systematic comparisons between finite and infinite square QWs remain scarce. We present a comprehensive study of GaAs/In$_x$Ga$_{1-x}$As/GaAs heterostructures…

Measurement results of the acoustoelectric effects (surface acoustic waves (SAW) attenuation and velocity) in a high-mobility $p$-SiGe/Ge/SiGe structure are presented. The structure was LEPECVD grown with a two dimensional (2D) channel…

We analyze the performance of a recently reported Ge/Si core/shell nanowire transistor using a semiclassical, ballistic transport model and an sp3s*d5 tight-binding treatment of the electronic structure. Comparison of the measured…

Germanium-silicon-germanium (Ge/Si$_{x}$Ge$_{1-x}$) heterostructures have emerged as a promising platform for hole-spin quantum technologies and high-mobility electronics, where strain and quantum confinement strongly reshape the Ge valence…

We have fabricated ambipolar transistors on chemically prepared hydrogen-terminated Si(111) surfaces, in which a two-dimensional electron system (2DES) or a two-dimensional hole system (2DHS) can be populated in the same conduction channel…

The scalability of spin qubit devices is conditioned by qubit-to-qubit variability. Disorder in the host materials indeed affects the wave functions of the confined carriers, which leads to variations in their charge and spin properties.…

In modern GaAs/Al$_x$Ga$_{1-x}$As heterostructures with record high mobilities, a two-dimensional electron gas (2DEG) in a quantum well is provided by two remote donor $\delta$-layers placed on both sides of the well. Each $\delta$-layer is…

We have measured the conductivity of high-mobility (001) Si metal-oxide-semiconductor field effect transistors (MOSFETs) over wide ranges of electron densities n=(1.8-15)x10^11cm^2, temperatures T=30mK-4.2K, and in-plane magnetic fields…

Large-scale arrays of quantum-dot spin qubits in Si/SiGe quantum wells require large or tunable energy splittings of the valley states associated with degenerate conduction band minima. Existing proposals to deterministically enhance the…

We report on the design and demonstration of ${\beta}-(Al_{0.18}Ga_{0.82})_2O_3/Ga_2O_3$ modulation doped heterostructures to achieve high sheet charge density. The use of a thin spacer layer between the Si delta-doping and heterojunction…

For applications to sensor design, the product nxmu of the electron density n and the mobility mu is a key parameter to be optimized for enhanced device sensitivity. We model the carrier mobility in a two dimensional electron gas (2DEG)…

We present a contactless method that is capable of characterizing a high electron mobility transistor heterostructure at the wafer stage, right after its growth, before any production process has been attempted, to provide the equilibrium…

We analyze fluctuation of the layer thicknesses and its influence on the strain state of (In,Ga)As/(Al,Ga)As micro-tubes containing quantum well structures. In those structures a curved high-mobility two-dimensional electron gas (HM2DEG) is…

Single-layer transition metal dichalcogenide (TMD) WSe2 has recently attracted a lot of attention because it is a 2D semiconductor with a direct band-gap. Due to low doping levels it is intrinsic and shows ambipolar transport. This opens up…

We report on the transport measurements of two-dimensional holes in GaAs field effect transistors with record low densities down to 7*10^8 cm^{-2}. Remarkably, such a dilute system (with Fermi wavelength approaching 1 micrometer) exhibits a…

Traps at the semiconductor-oxide interface are considered as a major source of instability in strained Ge/SiGe quantum devices, yet the quantified study of their cryogenic behavior remains limited. In this work, we investigate…

We report the transport characteristics of both electrons and holes through narrow constricted crystalline Si "wall-like" long-channels that were surrounded by a thermally grown SiO2 layer. Importantly, as a result of the existence of fixed…

Large-area thin films of topological Dirac semimetal Na$_3$Bi are grown on amorphous SiO$_2$:Si substrates to realise a field-effect transistor with the doped Si acting as back gate. As-grown films show charge carrier mobilities exceeding…

We study DC and AC transport in low-density $p-$Si/SiGe heterostructures at low temperatures and in a broad domain of magnetic fields up to 18 T. Complex AC conductance is determined from simultaneous measurement of velocity and attenuation…

We present a few electron double quantum dot (QD) device defined in an isotopically purified $^{28}$Si quantum well (QW). An electron mobility of $5.5 \cdot 10^4 cm^2(Vs)^{-1}$ is observed in the QW which is the highest mobility ever…