We show that C incorporation kinetics depend significantly on the carbon concentration. The carbon substitutionality (fraction of substitutional incorporated carbon atoms) is strongly influenced by the growth conditions, such as growth temperature and Si growth rate. In addition, reduction in the growth temperature and increase of the growth rate can both increase the substitutional carbon fraction. This behavior is well described by a kinetic model, with the energy barrier and preexponential frequency factor decreasing with increasing carbon concentration. Very low carbon concentrations (in the dopant range) can be predominantly incorporated substitutionally, independent of the growth temperature. At higher C concentrations (in the percentage range), the substitutional carbon fraction is shifted to lower values. We predict the existence of an upper limit for substitutional C incorporation, with its value depending on the specific growth conditions.

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CISCuT - CIS on Cu-Tape - has been established as a new thin film technology, in which Cu/In/S based solar cells are continuously fabricated on a Cu-tape in a series of consecutive roll-to-roll processes. Flexible modules encapsulated into polymer foils are assembled by interconnecting stripes of this tape cell in a roof-tile manner in an automated assembly line. J-V characteristics that show efficiencies of 9 % so far and that have been certified by the Frauenhofer Institut Solare Energiesysteme are presented. Stability tests over more than 8000 hours show promising results. Best results obtained from cells and from modules that have automatically been assembled to different areas are compared. This comparison gives insight into how the different roll-to-roll processes including the assembling of the module influence the overall quality of the module. Latest results including the unique mechanical properties of CISCuT-based solar cells and modules are highlighted. An outlook on the future prospects of this exciting technology is given.

ZnSeIZnMnSe MOW structures are grown by MBE. In situ RHEED control allows one to lock the growth cycle on the phase of the RHEED oscillations so that lattice plane completion is achieved independent of beam flux fluctuations and other irregularities. The band-edge resonant optical properties of the structures are dominated by sharp and pronounced excitonic features. The influence of strain and confinement on these excitons. their localization and interaction with phonons are discussed.

We present experimental results on Hall mobilities of electrons in tensile strained Si1−yCy layers with a substitutional carbon yS=0.4%, but different concentrations of interstitial carbon. Although the lattice distortion due to misfit strain and hence, the band alignment are identical for all investigated samples, we find differences in electron mobility of nearly a factor 2 due to the varying concentration of interstitial carbon. For the highest interstitial C concentration (1×1020 cm−3), it was not even possible to obtain any reliable electrical data. We demonstrate that it is not sufficient to consider only strain in evaluating electrical properties of C containing layers. Specific growth conditions can lead to very different electrical properties due to the different amounts of interstitial C, even for pseudomorphically strained layers with the same lattice mismatch and band alignment.

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