Optical Properties of Semiconductor Nanostructures

Semiconductor laser light sources are fascinating devices, which are compact, efficient, reliable and can thus be found in many electronic devices we use every day. We developed a unique pump/probe system at the IR beamline of the SLS to perform a detailed characterisation of such devices, in particular Germanium and GeSn layers as a possibility to fabricate a laser for direct integration into a Si based optoelectronic platform.
In addition, we also make use of the high brilliance of the synchrotron infrared light to investigate gain and coherence in quantum cascade lasers devices and demonstrated transient mid-infrared studies of the electron dynamics and charge separation of Au and TiO2 decorated surfaces.


Peter Friedli
Linear and Non-Linear Spectroscopy of Semiconductors using Synchrotron Infrared

Richard Geiger
Direct bandgap Germanium for Si compatible lasing


Ultra-broadband infrared pump-probe spectroscopy using synchrotron radiation and a tuneable pump
Lee Carroll, Peter Friedli, Philippe Lerch, Jörg Schneider, Daniel Treyer, Stephan Hunziker, Stefan Stutz, and Hans Sigg
Rev. Sci. Instrum. 82 063101 (2011)

Direct-Gap Gain and Optical Absorption in Germanium Correlated to the Density of Photoexcited Carriers, Doping, and Strain
Lee Carroll, Peter Friedli, Stefan Neuenschwander, Hans Sigg, Stefano Cecchi, Fabio Isa, Daniel Chrastina, Giovanni Isella, Yuriy Fedoryshyn, and Jérôme Faist
Phys. Rev. Lett. 109 057402 (2012)

Direct observation of charge separation on Au localized surface plasmon
J. Sa, G. Tagliabue, P. Friedli, J. Szlachetko, H. M. Rittmann-Frank, F. Santomauro, C. J. Milne, and H. Sigg
Energy Environ. Sci. (2013)

Transient mid-IR study of electron dynamics in TiO2 conduction band
J. Sa, P. Friedli, R. Geiger, P. Lerch, M. H. Rittmann-Frank, C. J. Milne, J. Szlachetko, F. G. Santomauro, J. A. van Bokhoven, and M. Chergui
Analyst, vol. 138, no. 7, pp. 1966–1970 (2013)

Four-wave mixing in a quantum cascade laser amplifier
P. Friedli, H. Sigg, B. Hinkov, A. Hugi, S. Riedi, M. Beck, and J. M. Faist
Appl. Phys. Lett., vol. 102, no. 22, p. 222104 (2013)

Synchrotron infrared transmission spectroscopy of a quantum cascade laser correlated to gain models
P. Friedli, H. Sigg, A. Wittmann, R. Terazzi, M. Beck, A. Kolek, and J. M. Faist
Appl. Phys. Lett., vol. 102, no. 1, p. 012112, (2013)

Excess carrier lifetimes in Ge layers on Si
R. Geiger, J. Frigerio, M. J. Süess, D. Chrastina, G. Isella, R. Spolenak, J. Faist, and H. Sigg
Appl. Phys. Lett., vol. 104, no. 6, pp. 062106–062106 (2014)