Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 24: Poster Session: Ge/Si/SiC / III - V Semiconductors

HL 24.11: Poster

Montag, 26. März 2012, 16:00–19:00, Poster D

Morphology and atomic structure of InGaN surfaces — •Sabine Alamé¹, Christian Friedrich¹, Daria Skuridina¹, Duc Dinh¹, Norbert Esser², Michael Kneissl¹, and Patrick Vogt¹ — ¹TU Berlin, Institut für Festkörperphysik, Hardenbergstr. 36, 10623 Berlin, Germany — ²Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., Albert-Einstein-Str. 9, 12489 Berlin, Germany

Although In_xGa_1−xN alloys have received much interest over the last years, there is still only limited knowledge about their atomic surface structure. We present a study on the morphology and electronic properties of group-III and group-V polar In_xGa_1−xN surfaces with varying indium content (0 ≤ x ≤ 100), grown by metalorganic vapour phase epitaxy on sapphire substrate. In order to obtain clean surfaces, the samples were prepared by thermal annealing between 400^∘C and 800^∘C under ultra-high vacuum conditions and in nitrogen plasma. The surface morphology was measured by atomic force microscopy in tapping mode, surface symmetries were investigated by low energy electron diffraction. X-ray photoelectron spectroscopy (XPS) was used to study the binding configurations and electronic properties of the surface. We obtained contamination free In_0.15Ga_0.85N (0001) surfaces within a temperature range of 600^∘C - 760^∘C, showing stable (1x1), (1+1/6), (√3x√3)R30^∘, and (2x2) reconstructions, respectively. The results show that the amount of surface indium plays a crucial role for the formation of the surface reconstructions. For further investigation we compared indium-rich In_xGa_1−xN (000-1) layers (0.3 ≤ x ≤ 0.8) by means of numerically analyzed XPS core-level spectra.