n-type modulation-doped Si/SiGe heterostructures were grown on different types of partly relaxed SiGe buffer layers, which are required in this material system to obtain a large enough conduction band offset. The samples were characterized by

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Disorder has a tremendous impact on charge transport in crystalline compounds on the pseudo-binary line between Sb 2 Te 3 and GeTe. Directly after crystallization, the pronounced disorder on the cation sublattice renders crystalline Ge 1 Sb 2 Te 4 -a composition with a carrier density of the order of 10 20 cm-an Anderson insulator. Annealing, however, induces the reduction of disorder and eventually triggers an insulator-to-metal transition. This study presents data on the electrical properties, the optical conductivity, and structural properties of the pseudo-binary compositions between Ge 3 Sb 2 Te 6 and GeTe. In contrast to the preceding investigations, which rely on the annealing temperature for tuning the electrical properties, this study elucidates the impact of stoichiometry and demonstrates that the stoichiometry may be employed as an alternative control parameter for the metal-to-insulator transition. The combination of annealing temperature and stoichiometry, therefore, provides a rich playground for tailoring disorder and, as a consequence, the transport of charge.

This paper reports on the development of phosphorous doped microcrystalline silicon oxide (µc-SiO x :H) films as an emitter window layer in flat p-type silicon heterojunction (SHJ) solar cells featuring intrinsic a-SiO x :H buffer layers. We investigated the material properties of n-type µc-SiO x :H films grown at various input gas ratios and correlated the results of SHJ solar cells utilizing varying oxygen content and thickness of the emitter layer to the corresponding film properties. A maximum efficiency of 19.0% was achieved. The excellent short circuit current of 35.8 mA/cm2 for flat cells was attributed to the low optical losses in the emitter window.