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HL: Fachverband Halbleiterphysik

HL 41: Nitrides: InGaN

HL 41.2: Talk

Tuesday, March 15, 2011, 14:30–14:45, POT 51

Preparation of reconstructed In_xGa_1−xN(0001) surfaces — •C. Friedrich¹, A. Biermann¹, V. Hoffmann², N. Esser^1,3, M. Kneissl¹, and P. Vogt¹ — ¹TU Berlin, Inst. f. Festkoerperphysik EW6-1, Hardenbergstr. 36, 10623 Berlin, Germany — ²Ferdinand-Braun-Institut, Leibniz-Institut, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany — ³Leibniz-Inst. fuer Analytische Wissenschaften - ISAS e.V., Albert-Einstein Str. 9, 12489 Berlin, Germany

The In_xGa_1−xN(0001) is a promising alloy system to investigate the principal mechanisms for the formation of group-III-nitride surface reconstructions, such as metal adlayer formation on reconstructed GaN(0001) or intrinsic surface electron accumulation on InN(0001). However, there is still not much known about the atomic structure of In_xGa_1−xN(0001) grown by metal organic vapour phase epitaxy (MOVPE) mainly because the preparation of such surfaces is crucial for measurements in ultra high vacuum (UHV). Here were present results on In_0.15Ga_0.85N(0001) surfaces after annealing under UHV conditions and alternatively in nitrogen plasma at temperatures between 500 ^∘C and 800 ^∘C. Auger electron spectroscopy, low energy electron diffraction and atomic force microscopy measurements were performed to elucidate the chemical composition, symmetry and morphology. On clean surfaces we obtained a (1+1/6) symmetry similar to the pseudo-(1×1) surface as reported for GaN(0001). By changing the preparation conditions a (2×2) and (√3×√3)R30^∘ symmetry is formed. All surfaces exhibit different group-III to group-V ratios and differ significantly in morphology and roughness.