Polynomial inequalities representing polyhedra

Our main result is that every n-dimensional polytope can be described by at most (2n-1) polynomial inequalities and, moreover, these polynomials can explicitly be constructed. For an n-dimensional pointed polyhedral cone we prove the bound 2n-2 and for arbitrary polyhedra we get a constructible representation by 2n polynomial inequalities.Comment: 9 page

Plasma texturing and its influence on surface passivation

In this paper a proof of concept of a plasma texture developed for solar cell processing is presented. Currently the implementation of this step into standard cell processes is limited by the uniformity of the etching results. It was, however, successfully introduced into a photolithography based process for 2x2 cm²-cells, leading to a benefit in efficiency of up to 1%abs compared to untextured samples. The combination with emitter passivation by thermal oxide on the front side both steps apart from each other leading to an improvement of cell data shows a degradation of the effective diffusion length. This detrimental effect is assigned to defects generated at high oxidation or firing temperatures and demands further investigation and adjustment of the processing steps

Combinatorics in statistical physics

SIGLEAvailable from Bibliothek des Instituts fuer Weltwirtschaft, ZBW, Duesternbrook Weg 120, D-24105 Kiel / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Advanced processing steps for high efficiency solar cells based on EFG material

In the past few years the quality of Edge-defined Film-fed Growth (EFG) material has strongly improved and can now compete with most standard multicrystalline materials. The maximum conversion efficiency of solar cells based on high quality EFG material is at the moment mostly limited by the applied solar cell processing steps. The state-of-the-art high efficiency process at the University of Konstanz (UKN) in combination with some additional processing steps is presented. The latter include hydrogen passivation of bulk defects, texturisation of the front surface by remote SF6 plasma (most samples shown here were textured at IMEC), surface passivation using a silicon oxide / silicon nitride stack and the application of Laser Fired Contacts (LFC). Single additional processing steps are investigated as well as various combinations of additional processing steps