Regensburg 2002 – scientific programme

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HL: Halbleiterphysik

HL 17: GaN I

HL 17.4: Talk

Tuesday, March 12, 2002, 11:45–12:00, H17

Strong vertical alignement of GaN quantum dots stacked in multilayer: correlation length and depth resolved strains using x-ray grazing incidence techniques — •Virginie Chamard¹, Till H. Metzger², Metin Tolan¹, Edith Bellet-Amalric³, Bruno Daudin³, Henri Mariette³ und Christophe Adelmann³ — ¹Experimentelle Physik I, Dortmund University, Otto Hahn Str. 4, 44231 Dortmund, Germany — ²European Synchrotron Radiation Facility, BP 220, 38043 Grenoble Cedex, France — ³CEA-CNRS, Condensed Matter Departement, CEA/Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France

The current interest in self-organized growth of strained semiconductor nanostructures is based on the possibility to achieve novel optical and electronic properties. Among them, nitride compounds are especially interesting due to their application in the blue-UV wavelength range. Using the Stranski-Krastanow growth mode, GaN quantum dots (QDs) are obtained. For application, the QDs are embedded in an AlN matrix and stacked in multilayers. The resulting structure is investigated by x-ray grazing incidence techniques, which are non-destructive and provide depth resolution, averaged over a large number of QDs. Applying grazing incidence small angle x-ray scattering, we have quantified the strong vertical alignment of the dots. With grazing incidence diffraction, the strain state of the dots and the matrix in the multilayer is analysed as a function of depth. The vertical propagation of strains from one QD to the other through AlN may be the origin of the strong vertical correlation.