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DS: Fachverband Dünne Schichten
DS 3: Organic Electronics and Photovoltaics I (Joint Session DS/CPP/HL/O)
DS 3.8: Vortrag
Montag, 22. März 2010, 12:00–12:15, H8
Electrical characterization of operating OFETs using Kelvin Probe Force Microscopy — •Franziska Lüttich, Harald Graaf, Iulia G. Korodi, Daniel Lehmann, Dietrich R. T. Zahn, and Christian von Borczyskowski — Center for nanostructured Materials and Analytics, Chemnitz University of Technology, Germany
We present recent results on n-type organic field effect transistors (OFETs) using Atomic Force Microscopy (AFM) and Kelvin Probe Force Microscopy (KPFM). These studies allow the local potential in the channel of OFETs during operation to be determined. The transistor structures investigated differ in gate insulator treatment and substrate temperature during evaporation of the organic material.
All investigated top-contact OFETs were fabricated under high-vacuum conditions (p < 4 · 10−7 mbar) by evaporating PDI8-CN2 on top of a p-doped silicon substrate covered by a SiO2 layer. Gold- electrodes were evaporated through a shadow mask on top of the organic layer. The gate insulator modification was implemented prior to the substrate transfer into the vacuum chamber. For this purpose monolayers of N-octadecyltrichlorosilane (OTS) resulting in hydrophobic surfaces were employed. In the case of deposition at elevated temperature the substrate was kept at 130∘C.
These variations of preparation influence the structural and electronic properties of the OFET and result in changes of the charge carrier mobility. The effects observed indicate tuning possibilities for organic devices leading to increased charge carrier mobility.