26 research outputs found
Far-infrared absorption in parallel quantum wires with weak tunneling
We study collective and single-particle intersubband excitations in a system
of quantum wires coupled via weak tunneling. For an isolated wire with
parabolic confinement, the Kohn's theorem guarantees that the absorption
spectrum represents a single sharp peak centered at the frequency given by the
bare confining potential. We show that the effect of weak tunneling between two
parabolic quantum wires is twofold: (i) additional peaks corresponding to
single-particle excitations appear in the absorption spectrum, and (ii) the
main absorption peak acquires a depolarization shift. We also show that the
interplay between tunneling and weak perpendicular magnetic field drastically
enhances the dispersion of single-particle excitations. The latter leads to a
strong damping of the intersubband plasmon for magnetic fields exceeding a
critical value.Comment: 18 pages + 6 postcript figure
Zn-Se-Cd-S Interlayer Formation at the CdS/Cuâ‚‚ZnSnSeâ‚„ Thin-Film Solar Cell Interface
The chemical structure of the CdS/Cu2ZnSnSe4 (CZTSe) interface was studied by a combination of electron and X-ray spectroscopies with varying surface sensitivity. We find the CdS chemical bath deposition causes a "redistribution" of elements in the proximity of the CdS/CZTSe interface. In detail, our data suggest that Zn and Se from the Zn-terminated CZTSe absorber and Cd and S from the buffer layer form a Zn-Se-Cd-S interlayer. We find direct indications for the presence of Cd-S, Cd-Se, and Cd-Se-Zn bonds at the buffer/absorber interface. Thus, we propose the formation of a mixed Cd(S,Se)-(Cd,Zn)Se interlayer. We suggest the underlying chemical mechanism is an ion exchange mediated by the amine complexes present in the chemical bath
Zn Se Cd S Interlayer Formation at the CdS Cu2ZnSnSe4 Thin Film Solar Cell Interface
The chemical structure of the CdS/Cu2ZnSnSe4 (CZTSe) interface was studied by a combination of electron and X-ray spectroscopies with varying surface sensitivity. We find the CdS chemical bath deposition causes a "redistribution" of elements in the proximity of the CdS/CZTSe interface. In detail, our data suggest that Zn and Se from the Zn-terminated CZTSe absorber and Cd and S from the buffer layer form a Zn-Se-Cd-S interlayer. We find direct indications for the presence of Cd-S, Cd-Se, and Cd-Se-Zn bonds at the buffer/absorber interface. Thus, we propose the formation of a mixed Cd(S,Se)-(Cd,Zn)Se interlayer. We suggest the underlying chemical mechanism is an ion exchange mediated by the amine complexes present in the chemical bath
Quantum Transport in Semiconductor Nanostructures
I. Introduction (Preface, Nanostructures in Si Inversion Layers,
Nanostructures in GaAs-AlGaAs Heterostructures, Basic Properties).
II. Diffusive and Quasi-Ballistic Transport (Classical Size Effects, Weak
Localization, Conductance Fluctuations, Aharonov-Bohm Effect, Electron-Electron
Interactions, Quantum Size Effects, Periodic Potential).
III. Ballistic Transport (Conduction as a Transmission Problem, Quantum Point
Contacts, Coherent Electron Focusing, Collimation, Junction Scattering,
Tunneling).
IV. Adiabatic Transport (Edge Channels and the Quantum Hall Effect, Selective
Population and Detection of Edge Channels, Fractional Quantum Hall Effect,
Aharonov-Bohm Effect in Strong Magnetic Fields, Magnetically Induced Band
Structure).Comment: 111 pages including 109 figures; this review from 1991 has retained
much of its usefulness, but it was not yet available electronicall
Observation of audio-frequency edge magnetoplasmons in the classical two-dimensional electron gas
Entrepreneurial Supply Chain Management Competence: Performance of Manufacturing Small and Medium Enterprises
Experimental determination of the charge neutrality level of Poly[2 methoxy 5 2 ethylhexyloxy p phenylene vinylene] MEH PPV
Stochastic Model Predictive Control Utilizing Bayesian Neural Networks
Integrating measurements and historical data can enhance control systems through learning-based techniques, but ensuring performance and safety is challenging. Robust model predictive control strategies, like stochastic model predictive control, can address this by accounting for uncertainty. Gaussian processes are often used but have limitations with larger models and data sets. We explore Bayesian neural networks for stochastic learning-assisted control, comparing their performance to Gaussian processes on a wastewater treatment plant model. Results show Bayesian neural networks achieve similar performance, highlighting their potential as an alternative for control designs, particularly when handling extensive data sets
One-dimensional subband effects in the conductance of multiple quantum wires in Si metal-oxide-semiconductor field-effect transistors
Contains fulltext :
112832.pdf (publisher's version ) (Open Access
Direct observation of an inhomogeneous chlorine distribution in CH3NH3PbI3 xClx layers surface depletion and interface enrichment
X-ray spectroscopies have shown a higher chlorine concentration near the perovskite/TiO2 interface than throughout the rest of the perovskite film.</p