Viktor Christopoulos, Thomas Lainer, Michael Haas, Harald Fitzek, Ana Torvisco, Lukas Schuh, Judith Radebner, Odo Wunnicke, Roland Fischer, Michael Holthausen, Harald Stueger, Gerald Kothleitner
Herein a convenient synthetic method to obtain 2,2,3,3-tetrasilyltetrasilane 3 and 2,2,3,3,4,4-hexasilylpentasilane 4 on a multigram scale is presented. Proton-coupled 29Si NMR spectroscopy and single-crystal X-ray crystallography enabled unequivocal structural assignment. Owing to their unique properties, which are reflected in their nonpyrophoric character on contact with air and their enhanced light absorption above 250 nm, 3 and 4 are valuable precursors for liquid-phase deposition (LPD) and the processing of thin silicon films. Amorphous silicon (a-Si:H) films of excellent quality were deposited starting from 3 and characterized by conductivity measurements, ellipsometry, optical microscopy, and Raman spectroscopy.
Higher silanes with eight or more silicon atoms were synthesized on a multigram scale by a convenient synthetic method. Owing to their unique properties, including their nonpyrophoric nature when in contact with air and their enhanced light absorption above 250 nm, these silanes were found to be excellent precursors for the deposition of silicon films from solution (see picture).