Good things come to those who wait: More than 160 years after their discovery, we have determined the solid‐state structures of the classic organometallic compounds dimethylzinc and diethylzinc by using X‐ray crystallography and density functional theory. The study shows that the linear molecules form weak intermolecular interactions with small covalent contributions. Me2Zn undergoes a solid–solid phase transition at 180 K (see picture).

The dimethylzinc-bidentate ether adducts [Me 2 Zn(1,4-dioxane)] (1), [Me 2 Zn(1,2-dimethoxyethane)] (2) and [Me 2 Zn(1,4-thioxane)] (3) are used as precursors for the growth of vertically aligned zinc oxide (ZnO) nanowires (NWs) by liquid-injection, metal-organic (MO)CVD. The ZnO NWs are deposited on Si(111) and F-doped SnO 2 /glass substrates in the absence of a seed catalyst. The precursors (1) and (2) are used to deposit ZnO NWs at substrate temperatures of 450 8C and 500 8C, whilst higher deposition temperatures of 550-600 8C are necessary to obtain ZnO NWs using (3). X-ray diffraction (XRD) data show that the NWs grown from all three adduct precursors are deposited in the wurtzitic ZnO phase. Room-temperature photoluminescence (PL) data for the ZnO NWs grown using (1) and (2) show an intense peak at 3.28 eV due to near band-edge emission with a very low intensity of defect-related green luminescence at 2.42 eV. In contrast, room-temperature PL data for the ZnO NWs deposited using (3) is dominated by deep centre, defect-related emission at 2.42 eV. Auger electron spectroscopy (AES) shows that the ZnO films deposited from (1) and (2) are high purity with no detectable carbon, but the ZnO films grown from (3) are contaminated with sulfur (1 at.-%). Single-crystal X-ray structures show that (1) is polymeric containing bridging 1,4-dioxane ligands while (2)

Gut Ding braucht Weile: Mehr als 160 Jahre nach ihrer Entdeckung wurden nun die Festkörperstrukturen der klassischen metallorganischen Verbindungen Dimethylzink und Diethylzink mittels Röntgenkristallographie und Dichtefunktionalrechnung aufgeklärt. Zwischen den linearen Molekülen herrschen schwache intermolekulare Wechselwirkungen mit geringen kovalenten Anteilen. Me2Zn zeigt bei 180 K einen Übergang zwischen zwei festen Phasen (siehe Bild).

The solid state structure of dimethylcadmium, a classic organometallic compound with a long history, has remained elusive for almost a century. X-ray crystallography and density functional theory reveal similar phase behaviour as in dimethylzinc. The high temperature tetragonal phase, α-Me2Cd, exhibits two-dimensional disorder, while the low temperature monoclinic phase, β-Me2Cd, is ordered. Both phases contain linearly coordinated cadmium atoms. While the methyl groups are staggered in the α-phase, they are eclipsed in the β-phase.

Titanium-doped hafnium oxide films, TixHf1−xO2−δ, have been deposited with a Ti content of x = 0.1 and x = 0.5, by atomic layer deposition. The TixHf1−xO2−δ growth rate is lower compared with the growth rates of the individual binary oxides; however, the composition of the films is unaffected by the reduced growth rate. An 850  °C spike anneal and a 500  °C 30 min furnace anneal were performed, and the resulting film composition and structure was determined using medium energy ion scattering, x-ray diffraction, and transmission electron microscopy. The Ti0.1Hf0.9O2−δ films readily crystallize into a monoclinic phase during both types of annealing. By contrast, the Ti0.5Hf0.5O2−δ films remain amorphous during both annealing processes. Electrical characterization of the as-deposited Ti0.1Hf0.9O2−δ films yielded a dielectric constant of 20, which is slightly higher than undoped HfO2 films. The as-deposited Ti0.5Hf0.5O2−δ films showed a significant increase in dielectric constant up to 35. After a 500  °C 30 min anneal, the dielectric constant reduced slightly to 27. The leakage current density of the amorphous film remains relatively unaffected at 8.7×10−7 A/cm2 at −1 MV/cm, suggesting this composition/heat treatment is a candidate for future device dielectrics.