G. Landwehr

University of Würzburg

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

A. Waag

Technische Universität Braunschweig

138

W. Ossau

Leibniz University Hannover

D. R. Yakovlev

TU Dortmund University

D. Hommel

Łukasiewicz Research Network – PORT Polish Center for Technology Development

A. Forchel

University of Würzburg

G. Bacher

University of Duisburg-Essen

ВП

В. П. Кочерешко

Ioffe Institute

Th. Litz

University of Würzburg

M. Keim

Peoples' Friendship University of Russia

B. Jobst

Technical University of Munich

Cooperative Institutions

University of Würzburg

158

Russian Academy of Sciences

Physico-Technical Institute

Ioffe Institute

Centre National de la Recherche Scientifique

Philipps University of Marburg

Technische Universität Berlin

University of Bremen

Max Planck Institute for Solid State Research

Institute of Solid State Physics

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Oscillator strength of excitons and charged excitons in ZnSe/ZnMgSSe QWs with a 2DEG of low density

Physica E Low-dimensional Systems and Nanostructures (2000)

W. Ossau D. R. Yakovlev G. V. Astakhov В. П. Кочерешко J. Nürnberger

Trion

Oscillator strength

Biexciton

Free electron model

10.1016/s1386-9477(99)00088-0

Cite

Citations (2)

Magnetic polarons in a single diluted magnetic semiconductor quantum dot

Physical review. B, Condensed matter (2000)

А. А. Максимов G. Bacher A. H. McDonald V. D. Kulakovskiĭ A. Forchel

Quasi-zero-dimensional magnetic polarons in single ${\mathrm{Cd}}_{0.93}{\mathrm{Mn}}_{0.07}{\mathrm{T}\mathrm{e}/\mathrm{C}\mathrm{d}}_{0.6}{\mathrm{Mg}}_{0.4}\mathrm{Te}$ quantum dots have been studied by photoluminescence spectroscopy. By comparing the experimental data with model calculations, the energy, the internal magnetic field, and the volume of the magnetic polarons are obtained. Moreover, the magnetic environment of the recombining electron hole pair causes a distinct broadening of the emission line $(\ensuremath{\sim}4 \mathrm{meV})$ of one diluted magnetic single quantum dot. The alignment of the Mn-spins in high magnetic fields results in a linewidth narrowing of almost one order of magnitude and the linewidth becomes comparable to that of a nonmagnetic ${\mathrm{Cd}}_{0.93}{\mathrm{Mg}}_{0.07}{\mathrm{T}\mathrm{e}/\mathrm{C}\mathrm{d}}_{0.6}{\mathrm{Mg}}_{0.4}\mathrm{Te}$ reference sample.

Magnetic semiconductor

Laser linewidth

10.1103/physrevb.62.r7767

Cite

Citations (139)

Landau levels of the two-dimensional holes gas in GaAs with inclusion of the anisotropy of the band structure

Surface Science (1986)

E. Bangert G. Landwehr

Landau quantization

Cyclotron resonance

Shubnikov–de Haas effect

10.1016/0039-6028(86)91025-3

Cite

Citations (53)

Excitonic polaritons in quantum-well structures under Bragg-reflection conditions

JETP Letters (1995)

D. R. Yakovlev Г. Позина В. П. Кочерешко A. Waag W. Ossau

Reflection

Solid-state physics

Source

Cite

Citations (0)

Defect properties of ion-implanted nitrogen in ZnSe

Physical review. B, Condensed matter (2001)

K. Marbach Bernd Ittermann M. Füllgrabe M. Heemeier F. Kroll

Lattice sites and annealing behavior of implanted ${}^{12}\mathrm{N}$ in semi-insulating ZnSe are investigated by use of \ensuremath{\beta} radiation detected nuclear magnetic resonance (\ensuremath{\beta}-NMR). For room-temperature implantation only a small part of the N impurities is found at sites with full ${T}_{d}$ symmetry; this fraction is attributed to substitutional ${\mathrm{N}}_{\mathrm{Se}}.$ Above 500 K the population of this site increases and saturates at a 10 times higher value for $T>~950\mathrm{K}.$ This increase is assigned to the change of initially interstitial N $({\mathrm{N}}_{i}),$ isolated or part of a complex, to unperturbed ${\mathrm{N}}_{\mathrm{Se}}.$ An activation barrier ${E}_{a}=0.47(5)\mathrm{eV}$ is determined for this process representing an upper limit for the ${\mathrm{N}}_{i}$ migration energy. We do not observe configurations where ${\mathrm{N}}_{\mathrm{Se}}$ is bound to a diamagnetic partner, like the ${(V}_{\mathrm{Se}}{\ensuremath{-}\mathrm{Z}\mathrm{n}\ensuremath{-}\mathrm{N}}_{\mathrm{Se}}{)}^{+}$ complex.

Diamagnetism

Lattice (music)

10.1103/physrevb.63.241201

Cite

Citations (4)

Spin-lattice relaxation in semimagnetic CdMnTe/CdMgTe quantum wells

Physical review. B, Condensed matter (2000)

A. V. Scherbakov А. В. Акимов D. R. Yakovlev W. Ossau G. Landwehr

The spin-lattice relaxation dynamics of magnetic ions has been studied in semimagnetic semiconductor ${\mathrm{Cd}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}{\mathrm{T}\mathrm{e}/\mathrm{C}\mathrm{d}}_{0.88}{\mathrm{Mg}}_{0.12}\mathrm{Te}$ quantum wells $(x<~0.032),$ by means of a method based on optical detection of injected nonequilibrium phonons. The relaxation rate is an increasing function of Mn content, external magnetic field and lattice temperature. The energy of phonons active in the spin-lattice relaxation process is found to increase with magnetic field, which can be explained in terms of phonon-induced spin-flip transitions in clusters consisting of the next-nearest-neighbor magnetic ions.

Magnetic semiconductor

Lattice (music)

10.1103/physrevb.62.r10641

Cite

Citations (34)

Biexciton formation inCdxZn1−xSe

Physical review. B, Condensed matter (1997)

K. Herz T. Kümmell G. Bacher A. Forchel B. Jobst

The dimensionality dependence of the biexciton formation process is investigated by comparing (Cd,Zn)Se/ ZnSe quantum-dot and quantum-well structures using time-resolved photoluminescence (PL) spectroscopy. Modeling the onset of the biexciton PL signal with a system of rate equations, we obtain a biexciton formation coefficient of about $4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}{\mathrm{cm}}^{2}/\mathrm{p}\mathrm{s}$ for 35-nm quantum dots and of $0.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}{\mathrm{cm}}^{2}/\mathrm{p}\mathrm{s}$ for the quantum-well reference, respectively, indicating a distinct enhancement of the biexciton formation efficiency in quantum dots. By analyzing the spectral line shape of the PL signal, an increase of the biexciton binding energy from 6.4 meV in the case of the quantum-well reference, to 11.3 meV for the quantum dots, is determined.

Biexciton

10.1103/physrevb.56.15261

Cite

Citations (17)

Quantum Effects in Cyclotron Resonance inp-Type Tellurium

Physical Review Letters (1969)

Kenneth Button G. Landwehr C. C. Bradley Peter Große Benjamin Lax

Quantum effects of cyclotron resonance of holes have been observed in tellurium by using high-resolution HCN and ${\mathrm{D}}_{2}$O submillimeter laser spectrometers. The multiplicity of resonance absorption lines in both parallel and perpendicular directions with respect to the principal axis suggests complex energy surfaces with highly warped bands. In addition, cyclotron resonance of electrons thermally excited across the gap was obtained.

Tellurium

Cyclotron resonance

10.1103/physrevlett.23.14

Cite

Citations (32)

Exciton magnetic polarons in the semimagnetic alloysCd1−x−y

Physical review. B, Condensed matter (1994)

G. Mackh M. Hilpert D. R. Yakovlev W. Ossau H. Heinke

The semimagnetic semiconductors ${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathit{x}\mathrm{\ensuremath{-}}\mathit{y}}$${\mathrm{Mn}}_{\mathit{x}}$${\mathrm{Mg}}_{\mathit{y}}$Te grown by molecular-beam epitaxy have been studied by photoluminescence and photoluminescence excitation spectroscopy. It is shown that the Zeeman splittings of exciton states depend on the Mn content only and are independent of the Mg content, i.e., the carrier--Mn spin-exchange constants are not affected by the Mg incorporation. Exciton magnetic polarons have been studied using the method of selective excitation of the exciton luminescence. The partial substitution of Cd by Mg leads to a strong increase of the magnetic polaron energy from 12 meV in ${\mathrm{Cd}}_{0.85}$${\mathrm{Mn}}_{0.15}$Te to 28 meV in ${\mathrm{Cd}}_{0.70}$${\mathrm{Mn}}_{0.14}$${\mathrm{Mg}}_{0.16}$Te. This result emphasizes the strong dependence of the polaron energy on the conditions of the primary localization of the excitons. Time-resolved photoluminescence measurements yield polaron formation times of about 100 ps without pronounced differences between the quaternary and ternary alloys. But the gain in polaron energy within a fixed time interval increases with increasing Mg content. The independently controllable variation of magnetic and nonmagnetic properties in ${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathit{x}\mathrm{\ensuremath{-}}\mathit{y}}$${\mathrm{Mn}}_{\mathit{x}}$${\mathrm{Mg}}_{\mathit{y}}$Te alloys allows us to demonstrate the importance of the primary localization of excitons for the magnetic polaron formation in ${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathit{x}\mathrm{\ensuremath{-}}\mathit{y}}$${\mathrm{Mn}}_{\mathit{x}}$${\mathrm{Mg}}_{\mathit{y}}$Te as well as in ${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Mn}}_{\mathit{x}}$Te alloys.

Content (measure theory)

Photoluminescence excitation

10.1103/physrevb.50.14069

Cite

Citations (42)

Luminescence Studies on Plastic Stress Relaxation in ZnSe/GaAs(001)

physica status solidi (b) (2000)

J. Schreiber Uwe Hilpert L. H�ring L. Worschech Burkhard K√∂nig

A series of ZnSe/GaAs(001) samples grown with various epilayer thicknesses from 50 to 1800 nm is investigated to study the role of polar misfit dislocations in respect of their nucleation and propagation behavior in the process of layer strain relaxation. Photoluminescence spectroscopy and SEM cathodoluminescence, both applied at low temperatures, are exploited to investigate misfit dislocation configurations and related stress relief in the ZnSe epilayers. Expected effects concerning the asymmetry in the dislocation misfit arrangements and optical anisotropy could be proved and analyzed in the framework of a modified Dodson-Tsao-Model.

Cathodoluminescence

Stress relaxation

10.1002/1521-3951(200011)222:1<169::aid-pssb169>3.0.co;2-e

Cite

Citations (11)