Hannover 2020 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 14: Precision Measurements and Metrology
Q 14.4: Talk
Tuesday, March 10, 2020, 11:45–12:00, a310
Characterization of absorption mechanisms in semiconductors by intensity dependent deflection spectroscopy — •Walter Dickmann1,2, Tom Götze2, Mark Bieler2, and Stefanie Kroker1,2 — 1Technische Universität Braunschweig — 2Physikalisch-Technische Bundesanstalt Braunschweig
We report on a method for the characterization of optical absorption in semiconductors at photon energies below the bandgap energy. We use intensity dependent deflection spectroscopy to measure the optical absorption spatially resolved and to separate the occurring absorption mechanisms. To this end, we take advantage of the different intensity scaling of these mechanisms and extract the material parameters by fitting the intensity dependent absorption to an underlying physical model. The model takes into account relevant processes like phonon-assisted absorption, two-photon absorption and the dynamical Franz-Keldysh effect. These processes affect the refractive index and thus lead to a deflection of the probe beam that is measured. Our method enables a simple but sufficient determination of crucial optical loss properties in various semiconductor systems, e.g. substrates for optical components or solar cells.