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DF: Fachverband Dielektrische Festkörper

DF 10: Focus: Spatio-Temporal Multiscale Optical Spectroscopy Meets Functional Materials
(DF with O, CPP)

DF 10.3: Topical Talk

Mittwoch, 22. März 2017, 10:20–10:50, GER 37

Time-resolved characterization of photoactive materials using terahertz spectroscopy — •Rainer Eichberger — Helmholtz-Zentrum Berlin für Materialien und Energie, Germany

Charge carrier mobility and lifetime are key properties of photoactive semiconductor materials. To develop and better understand novel functional materials that enable direct conversion of sunlight into electricity or chemical fuels it is essential to characterize charge generation and separation as well as carrier transport and recombination processes with high time resolution and sensitivity. In conjunction, time-resolved terahertz spectroscopy (TRTS) and microwave conductivity (TRMC) can probe a broad photoconductivity time window from a few hundred femtoseconds to milliseconds. An additional advantage of TRTS is the possibility to measure frequency-dependent conductivity or mobility spectra by transferring the signal into the Fourier space, which gives a deeper insight into the nature of carrier transport and localization. We discuss the dynamics of photo-induced processes such as polaron formation in metal oxides and charge transport issues in polycrystalline chalcopyrite and kesterite thin films arising from carrier localization caused by bandgap fluctuations.