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Showing 1 to 20 of 48 for “"Two-dimensional electron gas"”.
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Probing (with) a two dimensional electron gas
Contains fulltext : 18733_probwia_t.pdf (Publisher’s version ) (Open Access)
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Tunneling spectroscopy of the two-dimensional electron gas
… the single particle density of states (DOS) of a two-dimensional electron system (2DES) in a GaAs/AlGaAs heterostructure. Using a technique that we call "Time Domain Capacitance Spectroscopy" (TDCS), we measure the complete current-voltage characteristics for tunneling into the 2DES without making …
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Single particle spectrum of the two dimensional electron gas
… in the study of highly correlated systems, two-dimensional systems (2DES) have proven difficult to probe spectroscopically. Typical energy scales are on the order of a millielectron volt (meV), requiring high resolution, while correlated states of interest, such as those found in the integer …
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Nonlinear transport in two-dimensional electron gas at large filling factors.
… electrical transport in high-mobility 2D electron gas (2DEG) forming in modulation-doped GaAs/AlGaAs quantum wells. Transport nonlinearities induced by a pure dc electric field as well as by coexisting dc and microwave fields were studied at very high Landau level filling factors. It was …
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A quantum Monte Carlo study of the two-dimensional electron gas
… both ground state and excited states of the two-dimensional electron gas. For ground state properties we have used variational and fixed-node diffusion Monte Carlo methods, the latter of which is a nearly exact method for a system of many fermions. With introduction of backflow and three-body …
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Transport studies of reentrant integer quantum Hall states forming in the two-dimensional electron gas
<p>The two dimensional electron gas subjected to a magnetic field has been a model system in contemporary condensed matter physics which generated many beautiful experiments as well as novel fundamental concepts. These novel concepts are of broad interests and have benefited other fields of …
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Ferroelectric System Dynamics and the Properties of Ferroelectric / Two-Dimensional Electron Gas Heterostructures: a Ginzburg–Landau Study
Understanding the electronic response of materials to applied electric fields is an outstanding goal in solid-state theory. One aspect of this goal is to accurately predict the electric polarization of certain materials and how that polarization changes the electronic structure of adjacent solids. …
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Competition and Coexistence of Screening Mechanisms in Ferroelectric Thin Films and Superlattices
… in ferroelectric materials, namely domains and two-dimensional electron gases. A more realistic electrostatic description of thin films, which accounts for the presence of a substrate has been derived. The electrostatic description of superlattices of alternating ferroelectric and paraelectric …
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Design, fabrication, and characterization of low-dimensional quantum devices
The realization of a two-dimensional electron gas in semiconductor heterostructures due to advanced epitaxial growth techniques has led to novel high-speed devices such as modulation-doped field effect transistors and quantum well lasers. High resolution lithography and pattern transfer techniques …
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Investigations of the quantum Hall effect in graphene
… with a review of the quantum Hall effect in the two-dimensional electron gas (2DEG); we review and discuss the Hartree-Fock method which has been successfully used to investigate various aspects of the quantum Hall effect in the 2DEG. We then utilize the Hartree-Fock method to investigate the …
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Terahertz waveguide spectroscopy of two-dimensional plasmons in GaAs
The electrical characteristics of high-mobility, two-dimensional electron gas (2DEG) systems, such as GaAs quantum wells, have been well-studied at low frequencies and in extreme conditions of high magnetic fields and ultralow temperatures. While high-frequency excitations of 2DEGs have been …
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Terahertz photomixing spectroscopy of two-dimensional semiconductor plasmons
… grating-gate detectors made from high mobility two-dimensional electron gas (2DEG) material. In recent years, these detectors have seen significant improvements in sensitivity and currently exhibit a noise equivalent power of 10^-8 W/sqrt(Hz) However, further improvements are essential for these …
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GaN electronics for high-temperature applications
… complexity and cost. At the same time, the two-dimensional electron gas induced by AlGaN/GaN heterostructures makes HEMTs be naturally depletion-mode devices. This thesis aims to demonstrate devices capable of high-temperature operation without extra cooling systems by combing gate …
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AlGaN/GaN HFET with composite 'slow/fast' gate
… transistors (HFET) include a record high-density two dimensional electron gas (2DEG) channel, high breakdown fields, temperature stability and chemical robustness. Radio Frequency (RF) switches based on such HFETs demonstrate very low insertion loss, high power handling capability and broad range …
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Ultra-high Mobility 2DEG Heterostructure Fabricate by Oxide Molecular Beam Epitaxy for Device Application
LaAlO3/SrTiO3 heterostructures with two-dimensional electron gas (2DEG) interface have been reported with remarkable electron transport properties, which is the demand for application of wide bandgap semiconductor devices in modern power electronics industries. Both LaAlO3 and SrTiO3 are stable …
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Development of high-performance GaN-based power transistors
… to fabricate large-periphery AlGaN / GaN high electron mobility transistors (HEMTs) for high current operation. A novel Ti / Al multi-layered contact scheme is then introduced to further reduce the contact resistance by inhibiting the Al diffusion during Ohmic contact annealing. Second, to …
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Quantum Monte Carlo: Applications of the Twist -Averaged Boundary Conditions and the Calculation of Forces
… to four different physical systems: the three dimensional electron gas (3DEG), the two dimensional electron gas (2DEG), the liquid 3He and the electronic surface. We studied the spin polarization transition of 3DEG with optimized wavefunctions including backflow and three-body correlations. We …
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Electron transport in confined structures in very high mobility GaAs in perpendicular magnetic fields
In this thesis we study properties of two-dimensional electron transport through constrictions in perpendicular magnetic fields. We present two sets of experiments, one focusing on properties in the integer quantum Hall effect the second looking at properties in the fractional quantum Hall effect …
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Quantum Semiconductor Structures Dressed with Terahertz Cavity Photons
… electrodynamics (cQED) deals with an ensemble of two-level atoms coupled with a single mode of electromagnetic fields in a cavity. The theory of atomic cQED is well-developed, allowing one to make precise predictions for the quantum dynamics of atom–photon hybrids, indispensable for realizing …
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Steuerung von Nb-2DEG-Nb Josephson-Kontakten mittels Strominjektion
… is to control the supercurrent by changing the electron concentration in the two-dimensional electron gas (2DEG) by the gate voltage. However the required voltages are relatively high effectively resulting in attenuation of a signal. Later it was shown that injection of hot carriers into the …
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