Experimental setup for camera-based measurements of electrically and optically stimulated luminescence of silicon solar cells and wafers

We report in detail on the luminescence imaging setup developed within the last years in our laboratory. In this setup, the luminescence emission of silicon solar cells or silicon wafers is analyzed quantitatively. Charge carriers are excited electrically (electroluminescence) using a power supply for carrier injection or optically (photoluminescence) using a laser as illumination source. The luminescence emission arising from the radiative recombination of the stimulated charge carriers is measured spatially resolved using a camera. We give details of the various components including cameras, optical filters for electro- and photo-luminescence, the semiconductor laser and the four-quadrant power supply. We compare a silicon charged-coupled device (CCD) camera with a back-illuminated silicon CCD camera comprising an electron multiplier gain and a complementary metal oxide semiconductor indium gallium arsenide camera. For the detection of the luminescence emission of silicon we analyze the dominant noise sources along with the signal-to-noise ratio of all three cameras at different operation conditions. © 2011 American Institute of Physics

Entwicklung und Erprobung von TiB2 als Kathodenmaterial fuer Aluminiumelektrolysezellen Schlussbericht

With 20 refs., 5 tabs., 29 figs.Copy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Ultrafast electron spin dynamics in ZnO and Zn

We probe the electron spin dynamics in ZnO and Zn1-xCoxO sol-gel films with time-resolved Faraday rotation spectroscopy. Dephasing times T2* on the order of nanoseconds are observed at room temperature due to charge-separated states. In ZnCoO the effective electron Landé g factor rises with increasing Co2+ concentration, providing the mean-field electron-Co2+ exchange energy N0α = +0.25 ± 0.02 eV