The 3rd International Workshop on Modulation Spectroscopy of Semiconductor Structures – 3rd MS3 Workshop took place at the Wrocław University of Technology (Wrocław, Poland) between 3rd and 5th July 2008.

For a third time, the MS3 Workshop became the forum for discussing the advances of photoreflectance, electroreflectance, contactless electroreflectance, thermoreflectance, differential reflectance and wavelength-modulated surface photovoltage spectroscopy.

In this special issue of physica status solidi (a), it is our great pleasure to present the most interesting of the 3rd MS3 Workshop contributions.

The organizers acknowledge Wrocław University of Technology and Foundation for Polish Science for the financial support of the Workshop.

A very sad news reached all scientists during the Workshop. Professor Fred H. Pollak, great scientist and Honorary Chairman of the 1st MS3 Workshop, passed away on June 19, 2008 at the age of seventy-three. Wishing to honor his memory, we include in this issue a short note by M. Muñoz and Y.-S. Huang, his former students and friends (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)