Papers by Author: D. Siche

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Authors: Rositza Yakimova, Chariya Virojanadara, Daniela Gogova, Mikael Syväjärvi, D. Siche, Karin Larsson, Leif I. Johansson
Abstract: We are aiming at understanding the graphene formation mechanism on different SiC polytypes (6H, 4H and 3C) and orientations with the ultimate goal to fabricate large area graphene (up to 2 inch) with controlled number of monolayers and spatial uniformity. To reach the objectives we are using high-temperature atmospheric pressure sublimation process in an inductively heated furnace. The epitaxial graphene is characterized by ARPES, LEEM and Raman spectroscopy. Theoretical studies are employed to get better insight of graphene patterns and stability. Reproducible results of single layer graphene on the Si-face of 6H and 4H-SiC polytypes have been attained. It is demonstrated that thickness uniformity of graphene is very sensitive to the substrate miscut.
Authors: D. Siche, M. Albrecht, J. Doerschel, K. Irmscher, H. J. Rost, M. Rossberg, D. Schulz
Abstract: Planar defects have been found in nitrogen doped 2" 4H-SiC crystals grown on off-axis seeds. The doping level was 1×1019cm-3, which is below the critical one for the thermally activated cubic stacking fault formation in the 4H matrix. Planar defects in the doped region are nucleated on the whole seed surface outside the growth facet. They are coexisting 15R and 6H lamellas of unitcell height as revealed by means of luminescence and high resolution transmission electron microscopy. These inclusions are preferably formed at the rim of the growth facet, where polytype change occurs after switching off the nitrogen flow during growth.
Authors: D. Siche, M. Albrecht, H. J. Rost, Andreas Sendzik
Abstract: C-plane substrates with off-orientation to <1120 > may stabilize the grown polytype, but the stacking fault density (SFD) increases from zero in the on-axis sample to 4500 cm-1 (7.7° off). The SF form preferentially at the seed-crystal-interface by a kinetically induced rearrangement of surface ad-atoms on m-facets. Most SF start in bundles with an average distance of 100 .m, which are subdivided in smaller bundles with 8 .m distance. They start preferentially from the upper corner of the vertical non-polar plane of bunched steps, which may be composed of small pyramids with m-facet surfaces. The dislocation density could decrease with increasing SFD by a pinning mechanism.
Authors: Jürgen Wollweber, V. Chévrier, D. Siche, Th. Duffar
Authors: H. J. Rost, J. Dolle, J. Doerschel, D. Siche, D. Schulz, Jürgen Wollweber
Authors: H. J. Rost, J. Doerschel, D. Schulz, D. Siche, Jürgen Wollweber
Authors: Jürgen Wollweber, H. J. Rost, D. Schulz, D. Siche
Authors: D. Schulz, J. Dolle, H. J. Rost, D. Siche, Jürgen Wollweber
Authors: D. Schulz, M. Lechner, H. J. Rost, D. Siche, Jürgen Wollweber
Authors: H. J. Rost, K. Irmscher, J. Doerschel, D. Siche, D. Schulz, Jürgen Wollweber
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