Synthesis and Characterization of Copper(I) Amidinates as Precursors for Atomic Layer Deposition (ALD) of Copper Metal

Luminescent Tetranuclear Copper(I) and Gold(I) Heterobimetallic Complexes: A Phosphine Acetylide Amidinate Orthogonal Ligand Framework for Selective Complexation

The synthesis of phosphine acetylide amidinate stabilized copper(I) and gold(I) heterobimetallic complexes was achieved by reacting ligand [{Ph2PC≡CC(NDipp)2}Li(thf)3] (Dipp=2,6-N,N'-diisopropylphenyl) with CuCl and Au(tht))Cl, yielding the eight membered ring [{Ph2PC≡CC(NDipp)2}2Cu2] and the twelve membered ring [{Ph2PC≡CC(NDipp)2}2Au2]. {Ph2PC≡CC(NDipp)2}2Cu2] features a Cu2 unit, which is bridged by two amidinate ligands, served as a metalloligand to synthesize the heterobimetallic CuI/AuI complexes [{(AuX)Ph2PC≡CC(NDipp)2}2Cu2] (X=Cl, C6F5). In these reactions, the central ring structure is retained. In contrast, when the twelve membered ring [{Ph2PC≡CC(NDipp)2}2Au2] was reacted with CuX (X=Cl, Br, I and Mes), the reaction led to the rearrangement of the central ring structure to give [{(AuX)Ph2PC≡CC(NDipp)2}2Cu2] (X=Cl, Br, I and Mes), which feature the same the eight membered Cu2 ring as above. These compounds were also synthesized by a one-pot reaction. The luminescent heterobimetallic complexes were further investigated for their photophysical properties.

The surface chemistry of the atomic layer deposition of metal thin films

In this perspective we discuss the progress made in the mechanistic studies of the surface chemistry associated with the atomic layer deposition (ALD) of metal films and the usefulness of that knowledge for the optimization of existing film growth processes and for the design of new ones. Our focus is on the deposition of late transition metals. We start by introducing some of the main surface-sensitive techniques and approaches used in this research. We comment on the general nature of the metallorganic complexes used as precursors for these depositions, and the uniqueness that solid surfaces and the absence of liquid solvents bring to the ALD chemistry and differentiate it from what is known from metalorganic chemistry in solution. We then delve into the adsorption and thermal chemistry of those precursors, highlighting the complex and stepwise nature of the decomposition of the organic ligands that usually ensued upon their thermal activation. We discuss the criteria relevant for the selection of co-reactants to be used on the second half of the ALD cycle, with emphasis on the redox chemistry often associated with the growth of metallic films starting from complexes with metal cations. Additional considerations include the nature of the substrate and the final structural and chemical properties of the growing films, which we indicate rarely retain the homogeneous 2D structure often aimed for. We end with some general conclusions and personal thoughts about the future of this field.

Towards understanding the first half-ALD cycle of Ag growth: adsorption and dissociation of silver(I) acetamidinates on the Ag(110) surface

The advancement of atomic layer deposition (ALD) techniques for the controlled growth of transition metal thin films is constantly growing due to the design and synthesis of novel organometallic (OM) precursors capable of facilitating precise deposition and clean film growth. In this context, acetamidinates have emerged as a highly promising family of OM precursors due to their exceptional attributes, including outstanding stability, favorable volatility, and reactivity at low evaporation and deposition temperatures. These unique properties make them a sought-after candidate for enabling ALD processes. Here we conducted an atomic-scale study to get an in-depth understanding of the first ALD partial reaction, which involves the adsorption and dissociation process of the silver acetamidinate on the Ag(110) surface. Our research sheds light on the multistep adsorption and breaking mechanism of the novel silver(I)-N,N'-dimethylacetamidinate precursor employed as the silver source. Since the difference in energy between the monomer and dimer phases of the precursor is only 1.92 eV, we have explored the adsorption states of both phases. The monomer adsorbs on the surface by occupying hollow (H) sites; after that, it dissociates and loses its ligand, adopting a perpendicular geometry via the formation of new Ag-N bonds with the pair of N atoms at the top sites of the surface. On the other hand, the dimer adsorbs on long-bridge sites (LB) with the pair of N atoms occupying top sites with the silver atoms from the surface. Next, the dimer loses a pair of N-Ag bonds on each ligand, reaching a more stable state of partial cleavage with a relative energy of -0.38 eV. After overcoming an energy barrier of 0.41 eV, the dimer loses the remaining pair of N-Ag bonds, and the silver atoms diffuse towards H sites. Finally, the ligands diffuse toward the adjacent channel in the [100] direction of the surface. A charge distribution analysis of the adsorption stages shows the evolution of the silver atoms from precursor to the metallic state.

Evaluation of tin nitride (Sn3N4) via atomic layer deposition using novel volatile Sn precursors

Novel Sn precursors, Sn(tbip)2, Sn(tbtp)2, and Sn(tbta)2, were synthesized and characterized using various analytical techniques and density functional theory calculations. These precursors contained cyclic amine ligands derived from iminopyrrolidine. X-ray crystallography revealed the formation of monomeric SnL2 with distorted seesaw geometry. Thermogravimetric analysis demonstrated the exceptional volatility of all complexes. Sn(tbtp)2 showed the lowest residual weight of 2.7% at 265 °C. Sn3N4 thin films were successfully synthesized using Sn(tbtp)2 as the Sn precursor and NH3 plasma. The precursor exhibited ideal characteristics for atomic layer deposition, with a saturated growth per cycle value of 1.9 Å cy-1 and no need for incubation when the film was deposited at 150-225 °C. The indirect optical bandgap of the Sn3N4 film was approximately 1-1.2 eV, as determined through ultraviolet-visible spectroscopy. Therefore, this study suggests that the Sn3N4 thin films prepared using the newly synthesized Sn precursor are suitable for application in thin-film photovoltaic devices.

Grafting Copper Atoms and Nanoparticles on Double-Walled Carbon Nanotubes: Application to Catalytic Synthesis of Propargylamine

The decoration of carbon nanotubes (CNTs) by metal nanoparticles (NPs) combines the advantages of a high specific surface material with catalytic properties of metal nanocrystals. Little work has been devoted to the decoration of CNTs with copper NPs, and no evidence of copper atomic decoration of CNTs has shown up until now. Herein, we demonstrate that the strong acidic oxidation of double-walled CNTs (dwCNTs) is very efficient for the decoration of the carbon surface by copper NPs and atoms. This treatment severely degraded the CNT walls and generated a large amount of disordered sp³ carbon. This amorphous carbon film bears many chemically active functions like carboxyl and hydroxyl ones. In such conditions, the CNT walls behave as very efficient ligands for the stabilization of copper obtained by the thermolysis of the mesityl precursor in organic solution under mild dihydrogen pressure. In addition to copper NPs, we evidenced the presence of a regular coverage with copper atoms over the dwCNTs. This nanocomposite catalyzes the quantitative synthesis of propargylamines via one A³-type coupling reaction. Five consecutive catalytic cycles with 100% yield could be performed with no loss of activity, and the combination of Cu supported on dwCNTs allows a facile recycling of the catalytic material.

The Complex Degradation Mechanism of Copper Electrodes on Lead Halide Perovskites

Lead halide perovskite solar cells have reached power conversion efficiencies during the past few years that rival those of crystalline silicon solar cells, and there is a concentrated effort to commercialize them. The use of gold electrodes, the current standard, is prohibitively costly for commercial application. Copper is a promising low-cost electrode material that has shown good stability in perovskite solar cells with selective contacts. Furthermore, it has the potential to be self-passivating through the formation of CuI, a copper salt which is also used as a hole selective material. Based on these opportunities, we investigated the interface reactions between lead halide perovskites and copper in this work. Specifically, copper was deposited on the perovskite surface, and the reactions were followed in detail using synchrotron-based and in-house photoelectron spectroscopy. The results show a rich interfacial chemistry with reactions starting upon deposition and, with the exposure to oxygen and moisture, progress over many weeks, resulting in significant degradation of both the copper and the perovskite. The degradation results not only in the formation of CuI, as expected, but also in the formation of two previously unreported degradation products. The hope is that a deeper understanding of these processes will aid in the design of corrosion-resistant copper-based electrodes.

New Volatile Perfluorinated Amidine-Carboxylate Copper(II) Complexes as Promising Precursors in CVD and FEBID Methods

In the present study, we have synthesised and characterised newly copper(II) complexes with the general formula [Cu2(NH2(NH=)CC2F5)2(µ-O2CRF)4], where RF = CF3, C2F5, C3F7, C4F9. Infrared spectroscopy, mass spectrometry with electron ionisation (EI MS), and density-functional theory (DFT) calculations were used to confirm compounds' composition and structure. The volatility of the compounds was studied using thermal analysis (TGA), EI MS mass spectrometry, variable temperature infrared spectroscopy (VT IR), and sublimation experiments. Research has revealed that these compounds are the source of metal carriers in the gas phase. The thermal decomposition mechanism over reduced pressure was proposed. TGA studies demonstrated that copper transfer to the gaseous phase occurs even at atmospheric pressure. Two selected complexes [Cu2(NH2(NH=)CC2F5)2(µ-O2CC2F5)4] and [Cu2(NH2(NH=)CC2F5)2(µ-O2CC3F7)4] were successful used as chemical vapour deposition precursors. Copper films were deposited with an evaporation temperature of 393 K and 453 K, respectively, and a decomposition temperature in the range of 573-633 K without the use of hydrogen. The microscopic observations made to investigate the interaction of the [Cu2(NH2(NH=)CC2F5)2(µ-O2CC2F5)4] with the electron beam showed that the ligands are completely lost under transmission electron microscopy analysis conditions (200 keV), and the final product is copper(II) fluoride. In contrast, the beam energy in scanning electron microscopy (20 keV) was insufficient to break all coordination bonds. It was shown that the Cu-O bond is more sensitive to the electron beam than the Cu-N bond.

Comparison of Ligand Architecture on Vapor Deposition Precursors: Synthesis, Characterization, and Reactivity of Volatile Cadmium Bis-Amidinate Complexes

The lack of low-temperature (<200 °C) and easy-to-handle vapor deposition precursors for cadmium has been a limitation for cadmium chalcogenide ALD. Here, the cadmium amidinate system is presented as a scaffold for vapor deposition precursor design because the alkyl groups can be altered to change the properties of the precursor. Thus, the molecular structure affects the precursor stability at elevated temperature, onset of volatility, and reactivity. Cadmium bis-N,N-diisopropylacetamidinate (1) was synthesized and evaluated for its thermal stability, volatility, and reactivity-properties relevant to ALD precursors. Compounds 2, cadmium bis-N,N-diisopropyltertertiarybutylamidinate, and 3, cadmium bis-N,N-diisopropylbutylamidinate, are analogous to 1 and were synthesized by substituting the alkyl group on the bridging carbon during amidinate synthesis. All three compounds are volatile under reduced pressure, and thermal stability studies showed 1 and 3 to be stable at 100 °C in solution for days to weeks, while 2 decomposed at 100 °C within 24 h. Solution phase reactivity studies show 1 to be reactive with thiols at room temperature in a stoichiometric manner. No reactivity with either bis-silyl sulfides or alkyl sulfides was observed up to 110 °C over more than 3 days. Overall, the cadmium amidinate compounds presented here show potential as precursors in ALD/CVD processing, which can contribute to research critical for semiconductor processing.

Charge-Carrier Dynamics at the CuWO4/Electrocatalyst Interface for Photoelectrochemical Water Oxidation

Unraveling the charge-carrier dynamics at electrocatalyst/electrode interfaces is critical for the development of efficient photoelectrochemical (PEC) water oxidation. Unlike the majority of photoanodes investigated for PEC water oxidation, the integration of electrocatalysts with CuWO₄ electrodes generally results in comparable or worse performance compared to the bare electrode. This is despite the fact that the surface state recombination limits the water oxidation efficiency with CuWO₄ electrodes, and an electrocatalyst ought to bypass this reaction and improve performance. Here, we present results that deepen the understanding of the energetics and electron-transfer processes at the CuWO₄/electrocatalyst interface, which controls the performance of such systems. Ni_0.75Fe_0.25O_y (denoted as Ni75) was chosen as a model electrocatalyst, and through dual-working electrode experiments, we have been able to provide significant insight into the role of the electrocatalyst on the charge-transfer process at the CuWO₄/Ni75 interface. We have shown a lack of performance improvement for CuWO₄/Ni75 relative to the bare electrode to water oxidation. We attribute this surprising result to water oxidation on the CuWO₄ surface kinetically outcompeting hole transfer to the Ni75 electrocatalyst interface.

The role of alkylamine in the stabilization of CuO nanoparticles as a determinant of the Al/CuO redox reaction

We report on a new strategy to synthesize Al/CuO nanothermites from commercial Al and ultra-small chemically synthesized CuO nanoparticles coated with alkylamine ligands. These usual ligands stabilize the CuO nanoparticles and prevent them from aggregating, with the goal to enhance the interfacial contact between Al and CuO particles. Using a variety of characterization techniques, including microscopy, spectroscopy, mass spectrometry and calorimetry (ATG/DSC), the structural and chemical evolution of CuO nanoparticles stabilized with alkylamine ligands is analyzed upon heating. This enables us to describe the main decomposition processes taking place on the CuO surface at low temperature (<500 °C): the ligands fragment into organic species accompanied with H2O and CO2 release, which promotes CuO reduction into Cu2O and further Cu. We quantitatively discuss these chemical processes highlighting for the first time the crucial importance of the synthesis conditions that control the chemical purity of the organic ligands (octylamine molecules and derivatives such as carbamate and ammonium ions) in the nanothermite performance. From these findings, an effective method to overcome the ligand-induced CuO degradation at low temperature is proposed and the Al/CuO nanothermite reaction is analyzed, in terms of onset temperature and energy released. We produce original structures composed of aluminium nanoparticles embedded in CuO grainy matrices exhibiting an onset temperature ∼200 °C below the usual Al/CuO onset temperatures, having specific combustion profiles depending on the synthesis conditions, while preserving the total amount of energy released.

Synthesis of volatile, reactive coinage metal 5,5-bicyclic amidinates with enhanced thermal stability for chemical vapor deposition

Coinage metal bicyclic amidinates for chemical vapor deposition.

A Novel Method for the Metallization of 3D Silicon Induced by Metastable Copper Nanoparticles

The development of efficient copper deposition processes in high-aspect-ratio silicon structures is still a key technological issue for the microelectronic industry. We describe here a new process for the deposition of copper thin films in three-dimensional (3D) structures induced by the decomposition of a copper amidinate precursor in solution under a moderate H₂ pressure. The reduction of a metal precursor under soft conditions (3 bar, 110 °C) affords the preparation of a high-purity, conformal metallic layer. We unveil a novel deposition mechanism driven by colloidal copper nanoparticles (NPs) in solution that behave as a reservoir of metastable metallic NPs that eventually condense as a solid film on all immersed surfaces. The film growth process is characterized by time-resolved analyses of the NPs in the colloidal state (nuclear magnetic resonance NMR and UV-vis spectra) and of the NPs and metallic layer on substrates (transmission electron microscopy TEM, and scanning electron microscopy SEM). Major deposition stages of this process are proposed and the conformal metallization of 3D silicon substrates is successfully achieved. This method is transposable to other metallic layers such as silver or nickel.

The Chemistry of Inorganic Precursors during the Chemical Deposition of Films on Solid Surfaces

The deposition of thin solid films is central to many industrial applications, and chemical vapor deposition (CVD) methods are particularly useful for this task. For one, the isotropic nature of the adsorption of chemical species affords even coverages on surfaces with rough topographies, an increasingly common requirement in microelectronics. Furthermore, by splitting the overall film-depositing reactions into two or more complementary and self-limiting steps, as it is done in atomic layer depositions (ALD), film thicknesses can be controlled down to the sub-monolayer level. Thanks to the availability of a vast array of inorganic and metalorganic precursors, CVD and ALD are quite versatile and can be engineered to deposit virtually any type of solid material. On the negative side, the surface chemistry that takes place in these processes is often complex, and can include undesirable side reactions leading to the incorporation of impurities in the growing films. Appropriate precursors and deposition conditions need to be chosen to minimize these problems, and that requires a proper understanding of the underlying surface chemistry. The precursors for CVD and ALD are often designed and chosen based on their known thermal chemistry from inorganic chemistry studies, taking advantage of the vast knowledge developed in that field over the years. Although a good first approximation, however, this approach can lead to wrong choices, because the reactions of these precursors at gas-solid interfaces can be quite different from what is seen in solution. For one, solvents often aid in the displacement of ligands in metalorganic compounds, providing the right dielectric environment, temporarily coordinating to the metal, or facilitating multiple ligand-complex interactions to increase reaction probabilities; these options are not available in the gas-solid reactions associated with CVD and ALD. Moreover, solid surfaces act as unique "ligands", if these reactions are to be viewed from the point of view of the metalorganic complexes used as precursors: they are bulky and rigid, can provide multiple binding sites for a single reaction, and can promote unique bonding modes, especially on metals, which have delocalized electronic structures. The differences between the molecular and surface chemistry of CVD and ALD precursors can result in significant variations in their reactivity, ultimately leading to unpredictable properties in the newly grown films. In this Account, we discuss some of the main similarities and differences in chemistry that CVD/ALD precursors follow on surfaces when contrasted against their known behavior in solution, with emphasis on our own work but also referencing other key contributions. Our approach is unique in that it combines expertise from the inorganic, surface science, and quantum-mechanics fields to better understand the mechanistic details of the chemistry of CVD and ALD processes and to identify new criteria to consider when designing CVD/ALD precursors.

Synthesis and crystal structures of two new tin bis-(carboranylamidinate) complexes

Reaction of 2 equiv. of the lithium carboranylamidinate Li[o-(C2H10B10)C(NCy)(NHCy)] with SnCl2 in THF afforded the stannylene compound bis(N,N'-dicyclohexylamidinatocarboranate)tin(II), SnII[o-(C2H10B10)C(NCy)(NHCy)]2 (1). A similar reaction of SnCl4 with 2 equiv. of Li[o-(C2H10B10)C(N i Pr)(NH i Pr)] unexpectedly afforded the known solvated penta-chlorido-stannate(IV) salt [Li(THF)4][SnCl5(THF)] as the main reaction product. Small amounts of the new chlorido-tin(IV) bis-(carboranylamidinate) bis(N,N'-diiso-propylamidinatocarboranate)chloridotin(IV), SnIVCl[o-(C2H10B10)C(N i Pr)(NH i Pr)][o-(C2H10B10)C(N i Pr)2] (2), were isolated as a by-product. Single-crystal X-ray structure analysis revealed a κC,κN-chelating coordination of the carboranylamidinate ligands in both 1 and 2. The Sn atom in 1 adopts a pseudo-trigonal-bipyramidal coordination under participation of a stereoactive lone pair. In 2, a trigonal-bipyramidal coordination of Sn is completed by a chlorido ligand.

Crystal and mol-ecular structures of two silver(I) amidinates, including an unexpected co-crystal with a lithium amidinate

The silver(I) amidinates bis-[μ-N1,N2-bis-(propan-2-yl)benzamidinato-κ2N1:N2]disilver(I), [Ag2(C13H19N2)2] or [Ag{PhC(N i Pr)2}]2 (1), and bis-(μ-N1,N2-di-cyclohexyl-3-cyclo-propyl-propynamidinato-κ2N1:N2)disilver(I), [Ag2(C18H27N2)2] or [Ag{cyclo-C3H5-C≡C-C(NCy)2}]2 (2a), exist as centrosymmetric dimers with a planar Ag2N4C2 ring and a common linear coordination of the metal atoms in the crystalline state. Moiety 2a forms a co-crystal with the related lithium amidinate, namely bis-(μ-N1,N2-di-cyclo-hexyl-3-cyclo-propyl-propynamidinato-κ2N1:N2)disilver(I) bis-(μ-N1,N2-di-cyclo-hexyl-3-cyclo-propyl-propynamidinato-κ3N1,N2:N1)bis-(tetra-hydro-furan-κO)lithium(I) toluene monosolvate, [Ag2(C18H27N2)2][Li2(C18H27N2)2(C4H8O)2]·C7H8 or [Ag{cyclo-C3H5-C≡C-C(NCy)2}]2[Li{cyclo-C3H5-C≡C-C(NCy)2}(THF)]2·C7H8, composed as 2a × 2b × toluene. The lithium moiety 2b features a typical ladder-type dimeric structure with a distorted tetra-hedral coordination of the metal atoms. In the silver(I) derivatives 1 and 2a, the amidinate ligand adopts a μ-κN:κN' coordination, while it is a μ-κN:κN:κN'-coordination in the case of lithium derivative 2b.

Monitoring the coordination of amine ligands on silver nanoparticles using NMR and SERS

Low size dispersity silver nanoparticles (ca. 6 nm) have been synthesized by the hydrogenolysis of silver amidinate in the presence of hexadecylamine. Combining NMR techniques with SERS and DFT modeling, it is possible to observe an original stabilization mechanism. Amidine moiety is strongly coordinated to the Ag(0) nanoparticles surface whereas HDA ligand is necessary to prevent agglomeration, although it is only weakly interacting with the surface.

Surface chemistry of copper metal and copper oxide atomic layer deposition from copper(ii) acetylacetonate: a combined first-principles and reactive molecular dynamics study

Atomistic mechanisms for the atomic layer deposition using the Cu(acac)₂ (acac = acetylacetonate) precursor are studied using first-principles calculations and reactive molecular dynamics simulations.

Synthesis of Cu, Zn and Cu/Zn brass alloy nanoparticles from metal amidinate precursors in ionic liquids or propylene carbonate with relevance to methanol synthesis

Microwave-induced decomposition of the transition metal amidinates {[Me(C(N(i)Pr)2)]Cu}2 (1) and [Me(C(N(i)Pr)2)]2Zn (2) in the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4]) or in propylene carbonate (PC) gives copper and zinc nanoparticles which are stable in the absence of capping ligands (surfactants) for more than six weeks. Co-decomposition of 1 and 2 yields the intermetallic nano-brass phases β-CuZn and γ-Cu3Zn depending on the chosen molar ratios of the precursors. Nanoparticles were characterized by high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM), dynamic light scattering and powder X-ray diffractometry. Microstructure characterizations were complemented by STEM with spatially resolved energy-dispersive X-ray spectrometry and X-ray photoelectron spectroscopy. Synthesis in ILs yields significantly smaller nanoparticles than in PC. β-CuZn alloy nanoparticles are precursors to catalysts for methanol synthesis from the synthesis gas H2/CO/CO2 with a productivity of 10.7 mol(MeOH) (kg(Cu) h)(-1).

Synthesis and Structural Characterization of a Series of Group 11 2,2-Dialkyl-1,3-dicyclohexylguanidinate Complexes

The addition of either lithium dimethylamide or lithium diethylamide to a tetrahydrofuran (THF) solution of 1,3-dicyclohexylcarbodiimide yielded THF adducts of lithium 2,2-dimethyl-1,3-dicyclohexylguandidinate (1) and lithium 2,2-diethyl-1,3-dicyclohexylguandidinate (2), respectively. One equivalent of either 1 or 2 was subsequently reacted with one equivalent of Group 11 halide (CuCl, AgBr, and AuCl) to generate oligonuclear complexes with the general formula {M[CyNC(NR2)NCy]}n where M, R, and n are respectively Cu, CH3, 2 (3); Cu, CH2CH3, 2 (4); Ag, CH3, 3 (5); Ag, CH2CH3, 3 (6); Au, CH3, 2 (7); and Au, CH2CH3, 2 (8). Compounds 1–8 were characterized by single-crystal X-ray diffraction. The bulk powders for all complexes were found to be in agreement with the crystal structures based on elemental analyses, Fourier transform infrared spectroscopy, and 1H, 13C, and 7Li NMR studies. The unique structural aspects of this family of Group 11 complexes are highlighted.

CVD of pure copper films from novel iso-ureate complexes

We report the synthesis and characterisation of a new family of copper(i) metal precursors based around alkoxy-N,N'-di-alkyl-ureate ligands, and their subsequent application in the production of pure copper thin films. The molecular structure of the complexes bis-copper(i)(methoxy-N,N'-di-isopropylureate) (1) and bis-copper(i)(methoxy-N,N'-di-cyclohexylureate)(5) are described, as determined by single crystal X-ray diffraction analysis. Thermogravimetric analysis of the complexes highlighted complex 1 as a possible copper CVD precursor. Low pressure chemical vapour deposition (LP-CVD) was employed using precursor 1, to synthesise thin films of metallic copper on ruthenium substrates under an atmosphere of hydrogen (H2). Analysis of the thin films deposited at substrate temperatures of 225 °C, 250 °C and 300 °C, respectively, by SEM and AFM reveal the films to be continuous and pin hole free, and show the presence of temperature dependent growth features on the surface of the thin films. Energy dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (PXRD) and X-ray photoelectron spectroscopy (XPS) all show the films to be high purity metallic copper.