TY  - JOUR
A1  - Talalaev, V
A1  - Tomm, JW
A1  - Elsaesser, T
A1  - Zeimer, Ute
A1  - Fricke, J
A1  - Knauer, A
A1  - Kissel, H
A1  - Weyers, Markus
A1  - Tarasov, GG
A1  - Grenzer, Jörg
A1  - Pietsch, Ullrich
T1  - Carrier dynamics in laterally strain-modulated InGaAs quantum wells
N2  - We investigate the transient recombination and transfer properties of nonequilibrium carriers in an In0.16Ga0.84As/GaAs quantum well (QW) with an additional lateral confinement implemented by a patterned stressor layer. The structure thus contains QW- and quantum-wire-like areas. At low excitation densities, photoluminescence (PL) transients from both areas are well described by a rate equation model for a three-level system with a saturable interlevel carrier transfer representing the lateral drift of carriers from the QW regions into the wires. Small-signal carrier lifetimes for QW, wires, and transfer time from QW to wire are 180, 190, and 28 ps, respectively. For high excitation densities the time constants of the observed transients increase, in agreement with the model. In addition, QW and wire PL lines merge indicating a smoothening of the potential difference, i.e., the effective carrier confinement caused by the stressor structure becomes weaker with increasing excitation. (c) 2005 American Institute of Physics
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Zeimer, Ute
A1  - Pietsch, Ullrich
A1  - Grenzer, Joerg
A1  - Fricke, J.
A1  - Knauer, A.
A1  - Weyers, Markus
T1  - Optimised two layer overgrowth of a lateral strain-modulated nanostructure
N2  - Recently it has been shown that lateral carrier confinement in an InGaAs quantum well (QW) embedded in GaAs can be achieved by using a laterally patterned InGaP stressor layer on top of the heterostructure. To exploit this effect in a device the structure has to be planarized by a second epitaxial step. It has been shown that the lateral strain modulation almost vanishes after overgrowth with GaAs, whereas overgrowth with a single ternary layer of opposite strain compared to the stressor layer suffers from strain induced decomposition. Here we show that the lateral carrier confinement of the initially free standing nanostructure can almost be maintained using a two step process for overgrowth, where a strained thin ternary layer is grown first followed by GaAs up to complete planarization of the patterned structure. Thickness and composition of the ternary layer are adjusted on the basis of finite element calculations of the strain distribution (FEM). The strain field achieved after overgrowth is probed by X-ray grazing- incidence diffraction (GID). (c) 2005 Elsevier B.V. All rights reserved
Y1  - 2005
SN  - 0925-8388
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Grenzer, Jörg
A1  - Grigorian, Souren A.
A1  - Weyers, Markus
A1  - Zeimer, Ute
A1  - Feranchuk, S.
A1  - Fricke, J.
A1  - Kissel, H.
A1  - Knauer, A.
A1  - Tränkle, G.
T1  - Nanoengineering of lateral strain-modulation in quantum well heterostructures
N2  - We have developed a method to design a lateral band-gap modulation in a quantum well heterostructure. The lateral strain variation is induced by patterning of a stressor layer grown on top of a single quantum well which itself is not patterned. The three-dimensional (3D) strain distribution within the lateral nanostructure is calculated using linear elasticity theory applying a finite element technique. Based on the deformation potential approach the calculated strain distribution is translated into a local variation of the band-gap energy. Using a given vertical layer structure we are able to optimize the geometrical parameters to provide a nanostructure with maximum lateral band-gap variation. Experimentally such a structure was realized by etching a surface grating into a tensile-strained InGaP stressor layer grown on top of a compressively strained InGaAs-single quantum well. The achieved 3D strain distribution and the induced band-gap variation are successfully probed by x-ray grazing incidence diffraction and low-temperature photoluminescence measurements, respectively
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Grigorian, Souren A.
A1  - Grenzer, Jörg
A1  - Feranchuk, S.
A1  - Zeimer, Ute
T1  - Grazing-incidence diffraction study of strain-modulated single quantum well nanostructures
Y1  - 2003
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Zeimer, Ute
A1  - Grenzer, Jörg
A1  - Grigorian, Souren A.
A1  - Fricke, J.
A1  - Gramlich, S.
A1  - Bugge, F.
A1  - Weyers, Markus
A1  - Trankle, G.
T1  - Influence of lateral patterning geometry on lateral carrier confinement in strain-modulated InGaAs- nanostructures
Y1  - 2003
ER  - 
TY  - JOUR
A1  - Rose, Dirk
A1  - Pietsch, Ullrich
A1  - Zeimer, Ute
T1  - Characterization of InGaAs single quantum wells buried in GaAs[001] by grazing incidence diffraction
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Darowski, Nora
A1  - Paschke, K.
A1  - Pietsch, Ullrich
A1  - Wang, K. H.
A1  - Forchel, Alfred
A1  - Baumbach, Tilo
A1  - Zeimer, Ute
T1  - Identification of a buried single quantum well within surface structurized semiconductors using depth resolved x-ray grazing-incidence diffraction
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Stömmer, Ralph
A1  - Zeimer, Ute
A1  - Pietsch, Ullrich
T1  - Diffuse Röntgenstreuung an LB-Filmen
Y1  - 1995
ER  - 
TY  - JOUR
A1  - Darowski, Nora
A1  - Pietsch, Ullrich
A1  - Zeimer, Ute
A1  - Smirnitzki, V.
A1  - Bugge, F.
T1  - Nondestructive analysis of a lateral GaAs nanostructure buried under AlGaAs using conventional high resolution and grazing incidence X-ray diffraction
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Grenzer, Jörg
A1  - Schomburg, E.
A1  - Lingott, I.
A1  - Ignotov, A. a.
A1  - Renk, K. F.
A1  - Pietsch, Ullrich
A1  - Rose, Dirk
A1  - Zeimer, Ute
A1  - Melzer, B. J.
A1  - Ivanov, S.
A1  - Schaposchnikov, S.
A1  - Kop'ev, P. S.
A1  - Pavel'ev, D. G.
A1  - Koschurinov, Yu.
T1  - X-ray and transport characterization of an Esaki-Tsu superlattice device
Y1  - 1998
ER  -