Tailoring precursors for deposition:synthesis structure and thermal studies of cyclopentadienyl copper(I) isocyanide complexes

We report here the synthesis and characterization of a family of copper­(I) metal precursors based around cyclopentadienyl and isocyanide ligands. The molecular structures of several cyclopentadienylcopper­(I) isocyanide complexes have been unambiguously determined by single-crystal X-ray diffraction analysis. Thermogravimetric analysis of the complexes highlighted the isopropyl isocyanide complex [(η⁵-C₅H₅)­Cu­(CNⁱPr)] (<b>2a</b>) and the <i>tert</i>-butyl isocyanide complex [(η⁵-C₅H₅)­Cu­(CN^tBu)] (<b>2b</b>) as possible copper metal chemical vapor deposition (CVD) precursors. Further modification of the precursors with variation of the substituents on the cyclopentadienyl ligand system (varying between H, Me, Et, and ⁱPr) has allowed the affect that these changes would have on features such as stability, volatility, and decomposition to be investigated. As part of this study, the vapor pressures of the complexes <b>2b</b>, [(η⁵-MeC₅H₄)­Cu­(CN^tBu)] (<b>3b</b>), [(η⁵-EtC₅H₄)­Cu­(CN^tBu)] (<b>4b</b>), and [(η⁵-ⁱPrC₅H₄)­Cu­(CN^tBu)] (<b>5b</b>) over a 40–65 °C temperature range have been determined. Low-pressure chemical vapor deposition (LP-CVD) was employed using precursors <b>2a</b> and <b>2b</b> to synthesize thin films of metallic copper on silicon, gold, and platinum substrates under a H₂ atmosphere. Analysis of the thin films deposited onto both silicon and gold substrates at substrate temperatures of 180 and 300 °C by scanning electron microscopy and atomic force microscopy reveals temperature-dependent growth features: Films grown at 300 °C are continuous and pinhole-free, whereas films grown at 180 °C consist of highly crystalline nanoparticles. In contrast, deposition onto platinum substrates at 180 °C shows a high degree of surface coverage with the formation of high-density, continuous, and pinhole-free thin films. Powder X-ray diffraction and X-ray photoelectron spectroscopy (XPS) both show the films to be high-purity metallic copper

Synthesis, Structure and CVD Studies of the Group 13 Complexes [Me₂M{tfacnac}] [M = Al, Ga, In; Htfacnac = F₃CC(OH)CHC(CH₃)NCH₂CH₂OCH₃]

A family of group 13 metal dimethyl complexes of the general form [Me2M{ MeC(O)CHC(NCH2CH2OMe)CF3}] (M = Al (2), Ga (3) or In (4)) have been synthesised by reaction of the isolated free ligand (1) with the corresponding trimethyl-metal reagents. The isolated complexes (2-4) were characterised by elemental analysis, NMR spectroscopy, and the molecular structures of the complexes were determined by single crystal X-ray diffraction which reveals the compounds to be monomeric 5 coordinate complexes with coordination of the pendent ether bearing lariat in the solid state. Thermogravimetric analysis showed complexes 2-4 all to have residual masses, at 200 °C, of 2.4% or less well below the value for the respective metal oxides, and vapour pressure measurements show the indium complex (4) to be an order of magnitude less volatile (0.09 Torr at 80 oC) than the Al (2) or Ga (3) derivatives despite being isoleptic systems. Complexes 2-4 have all been investigated for their utility in the LP-MOCVD growth of the respective metal oxides in the absence of additional oxidant at 400 °C on silicon substrates

Synthesis and characterization of fluorinated β-ketoiminate zinc precursors and their utility in the AP-MOCVD growth of ZnO:F

A novel family of zinc bis beta-ketoiminate complexes 2b-2h have been synthesized by reaction of the isolated free ligands (1a-h) with dimethylzinc. The isolated zinc complexes were characterized by elemental analysis, NMR spectroscopy, and in the case of 2b-d and 2f-h, the molecular structures of the complexes were determined by single crystal X-ray diffraction which reveals the compounds to be pseudo-octahedral 6-coordinate, monomeric homoleptic complexes in the solid state. TG analysis showed complexes 2b-f all to have residual masses at 400 °C of 10% or less, well below the value for ZnO and thus indicative of volatility. Of these systems 2b [Zn{MeC(O)CHC(NCH2CH2OMe)CF3}2] has been investigated for its utility in the AP-MOCVD growth of F –doped ZnO (ZnO:F) in the absence of additional oxidant at 400 °C on glass and silicon substrates

Precursors for p-Type Nickel Oxide: Atmospheric-Pressure Metal-Organic Chemical-Vapour Deposition (MOCVD) of Nickel Oxide Thin Films with High Work Functions

A series of unsymmetrical nickel beta-diketonate derivatives have been synthesised and structurally characterised for application as atmospheric-pressure metal-organic chemical vapour deposition (AP-MOCVD) precursors for nickel oxide.TMEDA)Ni[MeC(O) CHC(O) OEt](2) (TMEDA = tetramethylethylenediamine) was selected and used to deposit NiO films of varying thickness onto commercial indium tin oxide (ITO)-coated glass; the work function of the ITO was raised as a consequence

Synthesis and Materials Chemistry of Bismuth <i>Tris</i>-(di-i-propylcarbamate): Deposition of Photoactive Bi₂O₃ Thin Films

The bismuth carbamate Bi­(O₂CNPrⁱ₂)₃, a tetramer in the solid-state, has been synthesized and used to deposit mixtures of bismuth oxides by aerosol-assisted chemical vapor deposition (AACVD). The nature of the deposited oxide is a function of both temperature and run-time. Initially, δ-Bi₂O₃ is deposited, over which grows a thick layer of β-Bi₂O₃ nanowires, the latter having an increasing degree of preferred orientation at higher deposition temperatures. The photocatalytic activity of a thin film of δ-Bi₂O₃ for the degradation of methylene blue dye was found to be similar to that of a commercial TiO₂ film on glass, while the film overcoated with β-Bi₂O₃ nanowires was less active. Exposure of Bi­(O₂CNPrⁱ₂)₃ to controlled amounts of moist air affords the novel oxo-cluster Bi₈(O)₆(O₂CNPrⁱ₂)₁₂, whose structure has also been determined