Regensburg 2004 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 3: Quantenpunkte und -dr
ähte: Herstellung und Charakterisierung
HL 3.3: Vortrag
Montag, 8. März 2004, 10:45–11:00, H17
NANOENGINEERING OF LATERAL STRAIN-MODULATION IN QUANTUM WELL HETEROSTRUCTURES — •Jörg Grenzer1, S.A. Grigorian1, S. Feranchuk1, U. Pietsch1, U. Zeimer2, J. Fricke2, H. Kissel2, A. Knauer 2, and M. Weyers2 — 1University of Potsdam, Institute of Physics, Am Neuen Palais 10, 14469 Potsdam, Germany — 2Ferdinand-Braun-Institut fuer Hoechstfrequenztechnik, Albert-Einstein-Str. 11, 12489, Berlin, Germany
We have developed a method to design a lateral band-gap modulation in a single quantum well heterostructure (SQW). The lateral strain variation is induced by patterning of a stressor layer grown on top of the SQW which itself is not patterned. The 3D strain distribution is calculated using linear elasticity theory implemented trough a finite element method (FEM). The local variation of the band-gap energy is derived from the strain distribution with the help of the deformation potential approach. For a given vertical layer structure we optimized 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 InGaP stressor layer grown on top of a InGaAs-SQW. The 3D strain distribution and the band-gap variation are probed by X-ray grazing incidence diffraction and photoluminescence (PL), respectively. We found a splitting of the PL line of about 50 meV as predicted by FEM. A planarization of the grating structure during a second epitaxy reduced the induced band-gap variation. However, for the planar structure we found still a splitting of larger than 22 meV.