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Ion implantation into (111) PZT films was done with 150 keV O+-ions using the following doses: 5 · 1010 cm-2 and 5 · 1013cm-2. The penetration depth of the O+-ion beam (through a 150 nm top Pt-electrode) was calculated with the TRIM. SP program version TRVMC95. For 104 particles, 22% of them were calculated to pass the top Pt electrode, 1% of the 104 particles were calculated to reach a penetration depth of 150 nm in PZT. The O+-implantation led to a significant improvement (50%) of loss factor tan δ. This effect is ascribed within current theory to a decrease of oxygen vacancies (defects). Oxygen vacancies are supposed to be associated by Ti3+, Ti2+ and Ti+centers in the perovskite lattice. Evidence for a possible participation of such reduced (charged) titanium defects was obtained by luminescence spectroscopy. Therefore, PZT samples were treated with H2 to increase the concentration of reduced Tin+ (n<4) ions in the perovskite lattice by chemical treatment. The luminescence spectrum of such reduced samples showed peaks at 3.2, 2.95 and 2.8 eV (surface Ti3+, Ti2+ Ti+ centers). Furthermore, peaks at 1.87eV and 2.2 eV were observed. These near-midgap states have been ascribed to transitions from Ti3+ and Ti2+ from the bulk of PZT (3.8 eV excitation energy, T = 6K). Finally, a sharp luminescence peak at 3.34 eV (6K) is assigned as self-trapped exciton luminescence.

The (trichlorosilyl) (and -germyl)metal carbonyls Co(CO)4SiCl3, Co(CO)4GeCl3, Mn(CO)5SiCl3, and cis-Fe(CO)4(SiCl3)2 have been synthesized in high yields. He I photoelectron spectra (UPS) of the complexes have been measured and interpreted on the basis of empirical arguments and density functional theory (DFT) calculations. For cis/trans-Fe(CO)4(SiCl3)2 isomers the calculations predict the trans-isomer to be more stable than cis by 15.2 kJ mol^-1. The cis-isomer is exclusively present in the solid state and in the gas phase. UPS results suggest the importance of charge polarization effects and the lack of π-back-donation along TM−Si bonds. The calculated M−Si bond distances amounted to 2.34 Å (Co−Si), 2.43 Å (Co−Ge), 2.47 Å (Mn−Si), 2.41 Å (trans-Fe−Si), and 2.45 Å (cis-Fe−Si). For Co(CO)4SiCl3, the DFT calculated Co−Si bond dissociation energy was 317.7 kJ mol^-1, compared to 222.2 kJ mol^-1 for Co−C energy in Co(CO)4CCl3.

The chemical vapor deposition (CVD) reaction of cis-Fe(SiCl3)2(CO)4 to form iron silicide, FeSi, has been investigated by in situ photoelectron (PE) spectroscopy in the surface-controlled regime up to 600 °C. The experimental data provide evidence for SiCl4 elimination. The reaction is assumed to occur at the surface via adsorbed silylene complex intermediates. A density functional theory (DFT) calculation approximated for the gas phase shows the elimination of SiCl4 to be endothermic by 15.0 kcal mol^-1. The mechanism considered in the calculations involves Cl transfer from Si1 to Si2 of cis-Fe(SiCl3)2(CO)4 accompanied by Fe−Si2 bond fission and formation of [Fe(&dbd;SiCl2)(CO)4] (calculated energy of activation 47 kcal mol^-1, Fe&dbd;Si bond dissociation energy 52 kcal mol^-1).