Epitaxial alloy films of Zintl-phase Ca(Si 1− xGe x) 2

• Published in: Journal of crystal growth 2001-03, Vol.223 (4), p.573-576
• Main Authors: Vogg, G., Miesner, C., Brandt, M.S., Stutzmann, M., Abstreiter, G.
• Format: Article
• Language: English
• Subjects: A1. X-ray diffraction; A3. Reactive deposition epitaxy; B1. Calcium compounds; B1. Germanium silicon alloys; Ca(Si 1− xGe x) 2; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Molecular, atomic, ion, and chemical beam epitaxy; Physics
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/S0022-0248(01)00686-8

Reactive deposition epitaxy growth of calciumgermanosilicides Ca(Si 1− x Ge x ) 2 with 0⩽ x⩽1 is described, starting from epitaxial Si 1− x Ge x films on Si(1 1 1) as well as pure Si(1 1 1) and Ge(1 1 1) as substrate material. The Ge content x of the Ca(Si 1− x Ge x ) 2 films formed is identical to that of the original Si 1− x Ge x films within experimental accuracy. Ca(Si 1− x Ge x ) 2 Zintl-phases show a trigonal rhombohedral crystal structure with a tr6 stacking sequence. While the c lattice constant is 30.6 Å independent of the Ge content, the a lattice constant increases linearly with x from a=3.855 Å for CaSi 2 to a=4.01 Å for CaGe 2. Ca(Si 1− x Ge x ) 2 is found to be unstable in ambient atmosphere and decomposes typically within some minutes.