Berlin 2012 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 44: Poster IV: Thin film photovoltaics; Organic electronics and photovoltaics (jointly with CPP, HL, O); Organic thin films; Trends in atomic layer deposition (Focused session)
DS 44.33: Poster
Freitag, 30. März 2012, 09:30–12:00, Poster E
Comparison of Structural Properties of Layers of Different Phthalocyanines on Reconstructed GaAs(001) Surfaces — •Linda Riele1,2, Benjamin Buick1, Ihor M. Kupchak3, Bjorn-Ove Fimland4, Patrick Vogt2, and Wolfgang Richter1 — 1Università di Roma Tor Vergata, Rome, Italy — 2TU Berlin, Berlin, Germany — 3V. Lashkaryov Institute of semiconductor physics NAS, Kyiv, Ukraine — 4Dept. of Electronics and Telecommunications, NTNU, Trondheim, Norway
The conductivity of organic layers depends crucially on the orientation and ordering of the molecules. Depending on the specific application in optoelectronic or electronic devices, a controlled growth of these layers on inorganic substrates is therefore desired. In this work we present a comparison of Raman scattering experiments of layers (up to 20 nm thick) of planar Cu phthalocyanines, and non-planar Pb phthalocyanines deposited on c(4× 4) and (2× 4) reconstructed surfaces of GaAs(001). The dependence of the molecular order on the surface reconstruction is analyzed by measuring the intensity of the Raman peaks as a function of sample rotation. We observe periodic intensity changes of the Pc vibrational modes with the rotation angle. These periodic changes have a fixed relation to the GaAs substrate phonons. This is an indication for well ordered Pc layers with a fixed geometrical relation to the substrate implying an epitaxial-like growth mode. DFT calculations allow a symmetry assignment of the vibrational modes (A1, B1, B2, etc.) and allow consequently model calculations with the different Raman tensors.