Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 25: Poster Session: GaN - Optical Properties & Preparation and Characterization & Devices

HL 25.2: Poster

Monday, March 26, 2012, 16:00–19:00, Poster D

Time Resolved Generallized Ellipsometry — •Christian Heinrichs, Chris Sturm, Helena Franke, Steve Linke, Tammo Böntgen, Rüdiger Schmidt-Grund, and Marius Grundmann — Universität Leipzig, Institut für Experimentelle Physik II, Linnéstr. 5, 04103 Leipzig, Germany

For the investigation of optical switching processes, change of the polarization in perovskite-based heterostructure, and its realization in devices, the change of the dielectric function (DF) as a function of time in dependence on the excitation is important up to the ps time scale. Ellipsometry is a suitable and sensitive tool for the determination of the DF. Up to now, no commercial ellipsometers are available which allow to perform time resolved measurements in this time regime. Therefore, we present a custom made ellipsometer setup which allows such measurements and devote special emphasis to the calibration routine, the data acquisition techniques, and the accuracy of the obtained data.

Our setup contains a linear polarizer and a compensator for both, the preparation of the polarization state of light and its analysis after reflection from a sample. Thereby we can measure the Stokes vector and determine the complete Mueller matrix. The signal is detected by a streak camera system which allows a time-resolution down to the ps range. The setup also allows PL measurements without changing the detection area on the sample at nearly the same time as the ellipsometry measurements. This allows a correlation of the time dependence of the luminescence processes and the corresponding contribution of the electronic components in the DF.