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Mild heating of the Zn(C5F6HO2)(2)center dot 2H(2)O center dot CH3(OCH2CH2)(2)OCH3 precursor allowed MOCVD deposition of ZnO films, in a low-pressure horizontal hot-wall reactor, on ITO substrates. The ZnO films were subsequently implanted with Sb ions. XRD measurements provided evidence that they consist of hexagonal, (002) and (101) oriented, crystals. UV-vis spectra showed that the transmittance of these films in the visible region is about 90%. The Sb implanted ZnO film showed a current-voltage characteristic that resembles that of a rectifying diode. This study represents the first example of Sb-implantation in ZnO films obtained by MOCVD.

A new tetraglyme adduct of sodium hexafluoroacetylacetonate [Na(hfa)·tetraglyme] has been synthesized and successfully used, together with the RE(hfa)3·diglyme (RE = Y, Yb, Er) complexes, in the synthesis of hexagonal phase NaYF4:Yb3+,Er3+ upconverting films through a facile sol–gel method.

Pr1–xCaxMnO3 thin films have been deposited through an in situ metal organic chemical vapor deposition (MOCVD) process using a molten multi-metal source, consisting of the Pr(hfa)3·diglyme, Ca(hfa)2·tetraglyme, and Mn(tmhd)3 precursor mixture on single crystal substrates such as LaAlO3 (001) and MgO (001). Optimization of processing parameters has allowed the deposition of homogeneous thin films in morphology, composition, and thickness. The effect of substrate has been assessed in relation to structure and morphology. Field emission scanning electron microscope of a Pr0.7Ca0.3MnO3 film deposited at 1000 °C on MgO (001).

An innovative sol–gel process, using a mixture of Na(hfa)·tetraglyme and RE(hfa)3·diglyme (RE = Y, Yb, Tm) complexes, has been optimized to produce upconverting β-NaYF4:Yb3+/Tm3+ thin films. The X-ray diffraction (XRD) analysis confirms that the new sol–gel preparation route yields reproducibly and selectively the hexagonal Na(Y1.5Na0.5)F6 structure (β-NaYF4) without any impurity phases, since no peaks of the cubic NaYF4, YOF, Y2O3 or NaF phases were observed. This final goal has been achieved through an accurate optimization of the operative parameters such as the molar ratio of the precursor mixture, the aging time of the sol, the spin coating procedure and the annealing temperature. Field-emission scanning electron microscopy (FE-SEM) images indicate that the morphology of the surfaces, grain dimensions and thickness are strongly related to the processing parameters, with the hexagonal phase films having a very uniform morphology. Energy dispersive X-ray (EDX) analyses established the film composition in terms of dopant ions, which are responsible for the upconverting properties of the material. Luminescence measurements under laser excitation at 980 nm confirmed the promising upconversion properties of the β-NaYF4:Yb3+/Tm3+ films.

Metal-Organic Chemical Vapor Deposition (MOCVD) has been applied to the fabrication of lanthanum cobaltite (LaCoO 3 ) films on MgO (001) and LaAlO 3 (001) substrates. The films have been deposited using a multi-metal source, consisting of the La (hfa) 3 •diglyme and Co (tta) 2 •tmeda (H-hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedione; diglyme = CH 3 O-(CH 2 CH 2 O) 2 CH 3 , Htta = α-thenoyltrifluoroacetone; tmeda = N,N,N′,N′-tetramethyl-ethylendiammine) precursor mixture. Structural and morphological characterization of films, carried out using X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM), proved the present MOCVD approach a suitable effective route for the growth of pure LaCoO 3 films. Composition and purity has been assessed through energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) analyses.

Thin films of CaCu3Ti4O12 (CCTO) are successfully deposited by metal-organic (MO)CVD on (001)SrTiO3 substrates. An interesting approach, based on a molten multi-component precursor source, is applied. The molten mixture consists of the Ca(hfa)2 center dot tetraglyme, Ti(tmhd)2(OiPr)2, and Cu(tmhd)2 [Hhfa?=?1,1,1,5,5,5-hexafluoro-2,4-pentanedione; tetraglyme?=?2,5,8,11,14-pentaoxapentadecane; Htmhd?=?2,2,6,6-tetramethyl-3,5-heptandione; OiPr?=?iso-propoxide] precursors. It is also found that, in the present case of a relatively large lattice mismatch (similar to 5%), the epitaxial growth can be achieved by a careful optimization of deposition parameters. Film structural and morphological characterization is carried out using several techniques; X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). A complete comparison between films deposited by two main processes is carried out in order to understand the kinetic and thermodynamic issues involved in the MOCVD epitaxial growth.

High-k films of CaCu3Ti4O12 are of interest for industrial multifunctional electronics. For oriented flow High Vacuum CVD processes, precursors are needed that they can be safely transported in the gas phase without carrier gas. We investigated the vapor pressure, and transport rate and temporal stability of a potential Ca precursor [Ca(hfa)2tgte] (hfa: hexafluoroacetylacetonate, tgte: tetraethylene glycol dimethyl ether) under HV conditions by varying the evaporation temperature. At 115{degree sign}C, the transport rate for the Ca(hfa)2tgte precursor of 4.3 mmol per hour was achieved allowing for high film deposition rates.

NiO thin films were grown through metalorganic chemical vapour deposition (MOCVD) on quartz and LaAlO3 (001) single crystal substrates. Two different volatile and thermally stable nickel β-diketonate adducts, Ni(hfa)2·tmeda and Ni(tta)2·tmeda [H-hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentandione; tmeda = N,N,N′,N′-tetramethylethylendiamine, Htta = 2-thenoyltrifluoroacetone], were applied as precursors for NiO film growth. The comprehensive study, applying two different precursors and changing the processing parameters, allowed for morphological control of the deposited NiO films. The AFM analyses indicated different values of roughness for NiO films obtained from the two different precursors and those from Ni(tta)2·tmeda showed a lower roughness. In addition, UV-Vis and ellipsometric measurements on NiO films grown from the Ni(tta)2·tmeda show higher transparency, fewer defects/impurities, better crystallinity and a higher refractive index than films deposited using the Ni(hfa)2·tmeda source. Raman spectroscopy confirmed the antiferromagnetic nature of the NiO layers. Work functions, around 5.1 eV, were measured by Kelvin Probe Force Microscopy for NiO films grown from Ni(tta)2·tmeda. The relationship between the precursor/substrate nature and film properties allowed us to define the best precursor and conditions for the MOCVD growth of good quality NiO films.

Calcium-doped praseodymium manganite films (Pr0.7Ca0.3MnO3, PCMO) were prepared by metal-organic chemical vapor deposition (MOCVD) on SrTiO3 (001) and SrTiO3 (110) single-crystal substrates. Structural characterization through X-ray diffraction (XRD) measurements and transmission electron microscopy (TEM) analyses confirmed the formation of epitaxial PCMO phase films. Energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) characterization was used to confirm lateral and vertical composition and the purity of the deposited films. Magnetic measurements, obtained in zero-field-cooling (ZFC) and field-cooling (FC) modes, provided evidence of the presence of a ferromagnetic (FM) transition temperature, which was correlated to the transport properties of the film. The functional properties of the deposited films, combined with the structural and chemical characterization collected data, indicate that the MOCVD approach represents a suitable route for the growth of pure, good quality PCMO for the fabrication of novel spintronic devices.

Metal-oxide-metal capacitors based on CaCu3Ti4O12 (CCTO) thin films, grown by metal-organic chemical vapor deposition and presenting a "brick wall" morphology, have been fabricated and characterized. In these capacitors, the coexistence of two Maxwell-Wagner related phenomena, i.e., the internal barrier layer capacitor and the electrode polarization effects, has been demonstrated and modeled. The detailed description of the involved mechanisms is discussed. High reliability and reproducibility in capacitors based on CCTO thin films can be achieved when the phenomena are controlled. A remarkable high capacitance density (about 100 nF/mm(2)) has been obtained at room temperature in optimised processing.

The physical properties of CaCu3Ti4O12 (CCTO) thin films grown by metal organic chemical vapor deposition on LaAlO3 substrates have been investigated. The structural, compositional, and optical characteristics have been evaluated, and all the collected data demonstrated that in the obtained (001) epitaxial CCTO thin films, a low defect density is present. The electrical behavior of the deposited thin films has been studied from both micro- and nanoscopic points of view and compared with the properties reported in the literature. The electrical measurements on large area capacitors indicated that in the investigated work frequency range (10(2)-10(6) Hz), the CCTO films possess dielectric constants close to the theoretically predicted "intrinsic" value and almost independent of the frequency. The nanoscopic dielectric investigation demonstrated that the deposited CCTO films possess n-type semiconducting nature and that a colossal extrinsic behavior can be locally achieved.

The discovery of the so called "giant dielectric permittivity phenomenon" in CaCu(3)Ti(4)O(12) (CCTO) perovskyte-related material reaching dielectric constant values up to 10(5) at room temperature, has generated a large interest for this material and related compounds. In this context, the study of the related oxide materials can be of great interest. In this work, we report on the results of a recent study of the deposition of Nd(2/3)Cu(3)Ti(4)O(12) (NCTO) thin films on Pt/TiO(2)/SiO(2)/Si(100) stacks by Metal-Organic Chemical Vapor Deposition (MOCVD). Nd(2/3)Cu(3)Ti(4)O(12) thin films have been deposited using a novel molten multi-metal source, ;onsisting of the Ti(tmhd)(2)(O-iPr)(2), Nd(hfa)(3)center dot diglyme, and Cu(tmhd)(2) (H-tmhd=2,2,6,6-tetramethyl-3,5-heptandione; O-iPr= iso-propoxide; H-hfa=1,1,1,5,5,5-hexafluoro-2,4-pentanedione; diglyme= CH(3)O(CH(2)CH(2)O)(2)CH(3)) precursor mixture. The structural and morphological characterization of films has been carried out using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Chemical compositional studies have been performed by energy dispersive X-ray (EDX) analysis and X-ray photoelectron spectroscopy (XPS). Structural and morphological characterizations point to formation of thin films having the correct stoichiometry and a sharp film/substrate interface structure

The increasing need to miniaturize capacitor devices is demanding for progressively higher dielectric constant materials. Recent studies have demonstrated that the calcium copper titanate, CaCu3Ti4O12 (CCTO), single crystals and ceramics possess impressive dielectric constant values of about 10 working at 1 MHz which remain constant in the 100-600K temperature range and slightly depend upon work frequency in the 10-10 Hz range. Fabrication of thin films becomes now a required issue to understand their properties and evaluate potentialities for device integration. The synthesis of a multi-element oxide phase often requires considerable efforts to define the appropriate deposition conditions for the fabrication of high quality thin films and in particular the MOCVD growth process depends critically on the availability of volatile, thermally stable precursors. CaCu3Ti4O12 (CCTO) thin films have been successfully deposited on LaAlO3 (100) single substrates and on Pt/TiO2/SiO2/Si(100) stacks using Metal Organic Chemical Vapor Deposition technique, a suitable method even for large-scale production. A novel approach based on a molten multi-component precursor source has been applied. The molten mixture consists of the Ca(hfa) 2 •tetraglyme, Ti(tmhd)2(i-Opr)2, and Cu(tmhd)2 [Hhfa= 1,1,1,5,5,5-hexafluoro-2,4-pentanedione; tetraglyme= 2,5,8,11,14-pentaoxapentadecane; Htmhd= 2,2,6,6-tetramethyl-3,5-heptandione; i-Opr = isopropoxide] precursors. 6-8 Film complete structural and morphological characterizations have been carried out by several techniques [X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM)]. The in-situ deposited CCTO (001) films on LaAlO3 (001) substrates are of high quality as evidenced by their inplane and out-of-plane alignments investigated using Xray and electron transmission diffraction patterns. CCTO films grown on Pt/TiO2/SiO2/Si(100) industrial substrates are polycrystalline (Figure 1) and present more disordered morphologies (Figure 2). Moreover, the electrical characterization at micro (Figure 2) and nanometer scale has been performed. The permittivity imaging provided at nanometer scale by Scanning Impedance Microscopy provided a correlation between the physical properties and structural characteristics. The nano impedance modulus and phase have been detected and the permittivity of the single CCTO layer has been calculated to be about 8000 at 90 kHz. Figure 1. XRD of CCTO polycrystalline films on Pt electrode and CCTO unit cell as inset.