Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 72: Poster Session: Si-based Photovoltaics / Inorganic Photovoltaics / Structure and Transport in Organic Photovoltaics / Organic Semiconductors
HL 72.30: Poster
Mittwoch, 28. März 2012, 16:00–19:00, Poster D
Toward the realization of a Scanning Near-field Optical Microscope deploying an Organic Light Emitting Device — Ilja Vladimirov1,2, •Benjamin Martini1,4, Daniela Donhauser1,3, Johannes Ostermann1,3, Michael Kröger1,3, and Wolfgang Kowalsky1,3 — 1Innovation Lab, Heidelberg — 2Universität Heidelberg, Kirchhoff-Institut für Physik — 3TU Braunschweig, Institut für Hochfrequenztechnik — 4TU München
We investigate a scanning near-field optical microscope (SNOM) employing an organic light emitting device (OLED) fabricated on a commercial atomic force microscope (AFM) cantilever via vacuum thermal evaporation and a method for its characterization. In order to deposit the OLED on a silicon cantilever, the OLED stack based on transparent ITO anode was adapted to silicon, the direction of light emission inverted and the out-coupling efficiency optimized. Employment of luminescent dopants led to OLED luminance values on silicon of about 1000 cd/m2 at 7 V.
Due to the low photon flux, estimated to be below 1000 photons/second, we use a photon counter, based on a cooled photomultiplier (PMT) to detect photons emitted from the AFM tip. To verify the applicability of near-field condition, we use a tapered optical fiber featuring a distribution of propagating modes significantly beyond the fiber core. This allows to detect coupling between the evanescent near-field of the probe and the modes of the tapered fiber using the PMT. Distance control between tip and sample is accomplished by an AFM.