Berlin 2005 – scientific programme

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O: Oberflächenphysik

O 36: Postersitzung (Elektronische Struktur, Grenzfl
äche fest-flüssig, Halbleiteroberfl
ächen und -grenzfl
ächen, Nanostrukturen, Oberfl
ächenreaktionen, Teilchen und Cluster, Struktur und Dynamik reiner Oberfl
ächen)

O 36.53: Poster

Monday, March 7, 2005, 15:00–18:00, Poster TU F

Investigation of InAs/AlAs(001) quantum dots using X-ray diffraction and FEM calculations — •Andriy Zolotaryov — Eißendorfer Str. 193, 21073 Hamburg

Nanoscale island structures are of great importance for applications exploiting quantum confinement effects. An exact knowledge of the crystalline and chemical properties of such structures plays a crucial role. Here we present a new method for the structural analysis of nanoisland systems using X-ray synchrotron radiation and final element calculation techniques. The InAs/AlAs(001) sample was grown using MBE. InAs final coverage was limited to 2.7 ML at a growth temperature of 500^∘C. The grazing incidence diffraction experiments were performed at the BW2 wiggler beam line on the DORIS storage ring at HASYLAB, DESY. Two 2D reciprocal space maps in the vicinity of the AlAs (202) and (220) Bragg positions were acquired. In order to analyse the diffraction data the theoretical calculations of the diffraction patterns have been performed based on InAs island growth simulations using finite-element (FEM) computations and the kinematical diffraction approximation. Trial-and-error fitting procedure has revealed the presence of two types of islands with different dimensions, chemical composition and surface density. STM and AFM measurements have confirmed correctness of the proposed model.