Single wire radial junction photovoltaic devices fabricated using aluminum catalyzed silicon nanowires.

Single nanowire radial junction solar cell devices were fabricated using Si nanowires synthesized by Al-catalyzed vapor-liquid-solid growth of the p(+) core (Al auto-doping) and thin film deposition of the n(+)-shell at temperatures below 650 °C. Short circuit current densities of 11.7 mA cm(-2) were measured under 1-sun AM1.5G illumination, showing enhanced optical absorption. The power conversion efficiencies were limited to < 1% by the low open circuit voltage and fill factor of the devices, which was attributed to junction shunt leakage promoted by the high p(+)/n(+) doping. This demonstration of a radial junction device represents an important advance in the use of Al-catalyzed Si nanowire growth for low cost photovoltaics.

Resolution of uncertainty of a four-stage sequential extraction procedure using analysis of variance.

Sequential extraction procedures are mostly applied to soils and sediments. Investigations were made for testing the applicability of a selected extraction scheme on spoil pile material. Therefore, different spoil pile samples from uranium mining were extracted into four steps (exchangeable, reducible, oxidizable, and aqua regia soluble phase) and the contents of the elements Cr, Cu, Fe, K, Ni, and Zn were analyzed. To substitute the sequential extraction by a sequence of single extractions and thus keep uncertainties of extraction on a low level, both procedures were compared regarding conformity of their results. The effects of sample handling as well as those of analysis on the measured metal contents were determined by means of analysis of variance and sources of uncertainties were discussed.