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Extremely cheap mesoporous silicon nanowires by metal‐assisted chemical etching of inexpensive metallurgical silicon have a higher porosity and thus volume expansion possibility than simple silicon nanowires. Metallurgical Si nanowires (MG‐SiNWs) show a reversible capacity of about 2111 mAh g−1 at a current rate of 0.2 C, an encouraging stability of over at least 50 cycles, and a good rate capability. [ABSTRACT FROM AUTHOR]

Mono- and multicrystalline solar cells have been stressed by potential-induced degradation (PID). Cell pieces with PID-shunts are imaged by SEM using the EBIC technique in plan view as well as after FIB cross-section preparation. A linear shaped signature is found in plan-view EBIC images at every potential-induced shunt position on both mono- and multicrystalline solar cells. Cross-sectional SEM and TEM images reveal stacking faults in a {111} plane. Combined TEM/EDX measurements show that the stacking faults are strongly decorated with sodium. Thus, the electric conductivity of stacking faults is assumed to arise under the influence of sodium ion movement through a high electric field across the SiN x anti-reflective layer, resulting in PID. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Abstract: Transmission electron microscopy (TEM) is a standard technique to characterize microelectronic device structures. As structures shrink to the nanoscale, surface damage produced by focused ion beam (FIB) sample preparation destroying the region of interest and degrading the resolution of TEM images becomes increasingly a problem. The thickness of the damaged layer at the sidewalls of a prepared cross section is around 20–30nm for silicon at typical beam energies of 30keV. In order to reduce these artifacts to a minimum low beam energies have been proposed for FIB polishing. We use a combination of molecular dynamics simulations and experiments to assess the influence of the focused ion beam on the surface structure of silicon for beam energies ranging from 1–5keV and a grazing angle of 10° typically used in low voltage FIB polishing. Under these conditions, the thickness of the amorphous layer depends linearly on the beam energy. Intrinsic surface stresses introduced by FIB are always tensile and of a magnitude of around 1GPa. [Copyright &y& Elsevier]

Abstract: Crystalline Si solar cells that exhibit potential-induced degradation of the shunting type (PID-s) are investigated on a microstructural level. Cell pieces with PID-shunts are imaged by SEM using the EBIC technique in order to investigate PID-s positions with high lateral resolution. ToF-SIMS depth profiles reveal Na accumulation localized at these shunt positions. Subsequently, cross-sectional FIB-lamellas of individual PID-shunts have been prepared. TEM is applied to a number of PID-s defects. TEM/EDX measurements reveal that stacking faults crossing the p–n junction are decorated with Na causing PID-s. These defects are further characterized by high resolution STEM methods down to the atomic scale. A model for the shunting mechanism in PID-s affected solar cells is developed. The results are discussed with respect to different shunting mechanisms. [Copyright &y& Elsevier]