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  - 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  - Srama, Ralf
A1  - Krueger, H.
A1  - Yamaguchi, T.
A1  - Stephan, T.
A1  - Burchell, M.
A1  - Kearsley, A. T.
A1  - Sterken, V.
A1  - Postberg, F.
A1  - Kempf, S.
A1  - Grün, Eberhard
A1  - Altobelli, Nicolas
A1  - Ehrenfreund, P.
A1  - Dikarev, V.
A1  - Horanyi, M.
A1  - Sternovsky, Zoltan
A1  - Carpenter, J. D.
A1  - Westphal, A.
A1  - Gainsforth, Z.
A1  - Krabbe, A.
A1  - Agarwal, Jessica
A1  - Yano, H.
A1  - Blum, J.
A1  - Henkel, H.
A1  - Hillier, J.
A1  - Hoppe, P.
A1  - Trieloff, M.
A1  - Hsu, S.
A1  - Mocker, A.
A1  - Fiege, K.
A1  - Green, S. F.
A1  - Bischoff, A.
A1  - Esposito, F.
A1  - Laufer, R.
A1  - Hyde, T. W.
A1  - Herdrich, G.
A1  - Fasoulas, S.
A1  - Jaeckel, A.
A1  - Jones, G.
A1  - Jenniskens, P.
A1  - Khalisi, E.
A1  - Moragas-Klostermeyer, Georg
A1  - Spahn, Frank
A1  - Keller, H. U.
A1  - Frisch, P.
A1  - Levasseur-Regourd, A. C.
A1  - Pailer, N.
A1  - Altwegg, K.
A1  - Engrand, C.
A1  - Auer, S.
A1  - Silen, J.
A1  - Sasaki, S.
A1  - Kobayashi, M.
A1  - Schmidt, J.
A1  - Kissel, J.
A1  - Marty, B.
A1  - Michel, P.
A1  - Palumbo, P.
A1  - Vaisberg, O.
A1  - Baggaley, J.
A1  - Rotundi, A.
A1  - Roeser, H. P.
T1  - SARIM PLUS-sample return of comet 67P/CG and of interstellar matter
JF  - EXPERIMENTAL ASTRONOMY
N2  - The Stardust mission returned cometary, interplanetary and (probably) interstellar dust in 2006 to Earth that have been analysed in Earth laboratories worldwide. Results of this mission have changed our view and knowledge on the early solar nebula. The Rosetta mission is on its way to land on comet 67P/Churyumov-Gerasimenko and will investigate for the first time in great detail the comet nucleus and its environment starting in 2014. Additional astronomy and planetary space missions will further contribute to our understanding of dust generation, evolution and destruction in interstellar and interplanetary space and provide constraints on solar system formation and processes that led to the origin of life on Earth. One of these missions, SARIM-PLUS, will provide a unique perspective by measuring interplanetary and interstellar dust with high accuracy and sensitivity in our inner solar system between 1 and 2 AU. SARIM-PLUS employs latest in-situ techniques for a full characterisation of individual micrometeoroids (flux, mass, charge, trajectory, composition()) and collects and returns these samples to Earth for a detailed analysis. The opportunity to visit again the target comet of the Rosetta mission 67P/Churyumov-Gerasimeenternko, and to investigate its dusty environment six years after Rosetta with complementary methods is unique and strongly enhances and supports the scientific exploration of this target and the entire Rosetta mission. Launch opportunities are in 2020 with a backup window starting early 2026. The comet encounter occurs in September 2021 and the reentry takes place in early 2024. An encounter speed of 6 km/s ensures comparable results to the Stardust mission.
KW  - Interstellar dust
KW  - Cometary dust
KW  - Churyumov Gerasimenko
KW  - Interplanetary dust
KW  - IMF
KW  - Cosmic vision
KW  - Sample return
KW  - Dust collector
KW  - Mass spectrometry
Y1  - 2012
U6  - https://doi.org/10.1007/s10686-011-9285-7
SN  - 0922-6435
SN  - 1572-9508
VL  - 33
IS  - 2-3
SP  - 723
EP  - 751
PB  - SPRINGER
CY  - DORDRECHT
ER  -