Berlin 2005 – scientific programme

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DS: Dünne Schichten

DS 18: Optische Spektroskopie dünner Schichten I

DS 18.4: Talk

Monday, March 7, 2005, 16:00–16:15, TU HS110

Raman investigations of metal contacts on organic thin films: reactivity, indiffusion, and metal morphology — •G. Salvan, B. A. Paez, L. Mancera, R. Scholz, and D.R.T. Zahn — Institut für Physik, Technische Universität Chemnitz, D-09107 Chemnitz, Deutschland

Metallic contacts are essential constituents in novel devices based on organic semiconductors. Here, in situ Raman scattering by internal and external vibrational modes in crystalline organic semiconductor layers is employed to assess issues like chemistry, indiffusion, and metal morphology at the metal/organic interfaces. As model systems two perylene derivatives, 3,4,9,10-perylene-tetracarboxylic dianhydride (PTCDA) and N,N’-dimethyl 3,4,9,10-perylene-tetracarboxylic diimide (DiMe-PTCDI) were investigated. Ag, In, and Mg were deposited onto organic layers grown on passivated GaAs(100). The results reveal that Ag and Mg form abrupt interfaces while In strongly diffuses into the organic layers. For Mg, however, the strong differences observed in the lineshape of the Raman bands compared to those induced by Ag and In indicate a reactive nature of the Mg/PTCDA interface. Mg films also exhibit the lowest degree of roughness.