Dresden 2014 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 108: Poster: Ultra-fast phenomena / Optical properties / Semiconductor laser / Devices and device concepts
HL 108.13: Poster
Donnerstag, 3. April 2014, 17:00–20:00, P1
The importance of an absolutely calibrated confocal photoluminescence setup — •Hendrik Sträter, Rudolf Brüggemann, Niklas Nilius, and Gottfried H. Bauer — Carl von Ossietzky Universität Oldenburg, Institut für Physik, D-26111 Oldenburg
Photoluminescence (PL) measurements provide a contact-less method to determinate the opto-electronic properties of a semiconductor and its potential as solar cell absorber material. From the recorded PL-spectrum it is possible to extract the integrated PL yield, splitting of quasi-Fermilevels (QFL), optical threshold, Urbach energy, and sub-gap absorption. Especially the QFL-splitting is an important quantity, since it can be interpreted as the maximum open circuit voltage (Voc), which can be achieved with a finally fabricated solar cell. Laterally resolved PL measurements are a powerful tool to determine fluctuations of the opto-electronic properties and correlations between the opto-electronic properties. Up to now it is often assumed that a spectrally calibrated PL setup is sufficient for determination of the variation of the QFL-splitting. This contribution shows that this is not always the case and that fluctuations of the QFL-splitting and all quantities correlated to it heavily depend on the absolute calibration function of the PL setup. A mathematical framework is presented which proves that even small deviations from the ideal calibration function can lead to arbitrary wrong results. Simulated and experimental PL results give an idea of the outcome of a wrong calibrated PL setup and a possible solution to the problem is presented.