Berlin 2008 – wissenschaftliches Programm

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SYSA: Symposium Tayloring Organic Interfaces: Molecular Structures and Applications

SYSA 5: Poster Session SYSA

SYSA 5.44: Poster

Dienstag, 26. Februar 2008, 14:30–20:00, Poster A

The temperature dependence of amorphous thin film growth: the case of α-NPD — •Phenwisa Niyamakom, Philip Schulz, Azadeh Farahzadi, Tobias Lau, and Matthias Wuttig — Institute of Physics (IA), RWTH Aachen University, 52056 Aachen, Germany

Both the substrate temperature during deposition and the deposition rate are important parameters, which have a pronounced influence on the morphology and related properties of an amorphous organic layer, including subsequently the device performance of OLEDs. We have studied the morphology and structural properties of N,N'-diphenyl-N,N'-bis(1-naphthyl)-1-1'biphenyl-4-4" diamine (α-NPD) films on silicon substrates by atomic force microscopy (AFM), X-ray reflectometry (XRR) and contact angle measurements. The α-NPD thin films have been deposited by vacuum thermal evaporation (VTE). A quantitative analysis of the AFM images has been performed to derive the surface morphology, surface roughness and correlation length. The film density and the surface roughness have been analyzed from XRR spectra. In addition, the surface free energy of α-NPD has been calculated from the contact angle in order to understand the wetting behavior of α-NPD on the silicon surface. From the data obtained, the evolution of α-NPD thin film growth with temperature dependence will be explained.