Growth of WOx from Tungsten(VI) Oxo-Fluoroalkoxide Complexes with Partially Fluorinated ß-Diketonate/ß-Ketoesterate Ligands: Comparison of Chemical Vapor Deposition to Aerosol-Assisted CVD.

Tungsten(VI) oxo complexes of the type WO(OR)3L [R = C(CH3)2CF3, C(CF3)2CH3, CH(CF3)2, L = hexafluoroacetylacetonate (hfac), ethyl trifluoroacetoacetonate (etfac), acetylacetonate (acac)] bearing partially fluorinated alkoxide and/or chelating ligands were synthesized. Thermal decomposition behavior and mass spectrometry (MS) fragmentation patterns of selected examples were studied. The thermolysis products of WO(OC(CF3)2CH3)3(hfac) were characterized by nuclear magnetic resonance and gas chromatography-MS. Studies of the sublimation behavior of the complexes demonstrated that their volatility depends on the degree of fluorination. Comparative studies of the deposition of tungsten oxide by chemical vapor deposition (CVD) and aerosol-assisted CVD were carried out using WO(OC(CF3)2CH3)3(hfac) as a single-source precursor. WOx materials were successfully deposited by both deposition methods, but the deposits differed in morphology, structure, and crystallinity.

N,N-Disubstituted-N'-acylthioureas as modular ligands for deposition of transition metal sulfides.

First row transition metal complexes (Ni, Co, Cu, Zn) with N,N-disubstituted-N'-acylthiourea ligands have been synthesized and characterized. Bis(N,N-diisopropyl-N'-cinnamoylthiourea)nickel was found to have the lowest onset temperature for thermal decomposition. Thin film deposition of Ni, Co, and Zn sulfides by aerosol assisted chemical vapor deposition from their respective N,N-diisopropyl-N'-cinnamoylthiourea complexes at 350 °C has been demonstrated.

Synthesis and evaluation of κ(2)-ß-diketonate and ß-ketoesterate tungsten(vi) oxo-alkoxide complexes as precursors for chemical vapor deposition of WOx thin films.

Reactions of [WO(OR)4]x (x = 1, 2) complexes with bidentate ligands (LH = acacH, tbacH, dpmH, tbpaH) afforded complexes : [WO(OCH3)3(acac) (); WO(OCH2CH3)3(acac) (); WO(OCH(CH3)2)3(acac) (); WO(OCH3)3(tbac) (); WO(OCH2CH3)3(tbac) (); WO(OCH(CH3)2)3(tbac) (); WO(OCH2CH3)3(dpm) (); WO(OCH(CH3)2)3(dpm) (); WO(OCH2C(CH3)3)3(acac) (); WO(OCH2C(CH3)3)3(tbac) (); WO(OCH2C(CH3)3)3(dpm) (); WO(OCH2C(CH3)3)3(tbpa) (); WO(OC(CH3)3)3(tbac) ()]. The synthesis is facilitated by the lability of the bridging ligands of the [WO(OR)4]2 complexes in solution, which provides a pathway for exchange of L with an alkoxide ligand. Thermogravimetric analysis and the conditions for sublimation or distillation of demonstrate that they have sufficient vapor pressure and thermal stability for volatilization in a conventional Chemical Vapor Deposition (CVD) reactor. High solubility in hydrocarbon and ether solvents establishes that the complexes are also potential candidates for Aerosol-Assisted Chemical Vapor Deposition (AACVD). AACVD from on ITO or bare glass resulted in growth of continuous, dense and amorphous thin films of substoichiometric WOx between 250-350 °C and nanorods of W18O49 above 350 °C.