Metal Foils with Ordered Crystal Structure and Method for Producing Metal Foils

A method for producing a metal foil comprising depositing metal onto an oxidizable substrate to form a metal film on the substrate; oxidizing the substrate at an interface between the metal film and the substrate; and removing the metal film from the substrate to yield a metal foil. A method for forming a thin metal film comprising pre-polarizing a single-crystal Si substrate by application of a potential which is negative of a potential at which Si oxidizes, which pre-polarization occurs in the presence of metal ions to form metal growth nucleation sites on the substrate, followed by application of a potential at which both oxidation of Si and electrodeposition of the metal occur to grow the metal film and oxidize the Si to SiOx, which potential is more positive than the potential applied in the pre-polarization step

Spincoating Epitaxial Films

A process for forming an epitaxial film comprising spinning a substrate having an ordered crystal structure ; heating the substrate during spinning to a temperature between 70° C. and 150° C .; dripping epitaxial film precursor solution onto the spinning substrate , where the precursor solution comprises inorganic film precursor material in a solvent ; and continuing the heating and spinning to remove the solvent and epitaxially grow the epitaxial film on the substrate

Epitaxial Electrodeposition Of Ordered Inorganic Materials

Conspectus The quality of technological materials generally improves as the crystallographic order is increased. This is particularly true in semiconductor materials, as evidenced by the huge impact that bulk single crystals of silicon have had on electronics. Another approach to producing highly ordered materials is the epitaxial growth of crystals on a single-crystal surface that determines their orientation. Epitaxy can be used to produce films and nanostructures of materials with a level of perfection that approaches that of single crystals. It may be used to produce materials that cannot be grown as large single crystals due to either economic or technical constraints. Epitaxial growth is typically limited to ultrahigh vacuum (UHV) techniques such as molecular beam epitaxy and other vapor deposition methods. In this Account, we will discuss the use of electrodeposition to produce epitaxial films of inorganic materials in aqueous solution under ambient conditions. In addition to lower capital costs than UHV deposition, electrodeposition offers additional levels of control due to solution additives that may adsorb on the surface, solution pH, and, especially, the applied overpotential. We show, for instance, that chiral morphologies of the achiral materials CuO and calcite can be produced by electrodepositing the materials in the presence of chiral agents such as tartaric acid. Inorganic compound materials are electrodeposited by an electrochemical-chemical mechanism in which solution precursors are electrochemically oxidized or reduced in the presence of molecules or ions that react with the redox product to form an insoluble species that deposits on the electrode surface. We present examples of reaction schemes for the electrodeposition of transparent hole conductors such as CuI and CuSCN, the magnetic material Fe3O4, oxygen evolution catalysts such as Co(OH)2, CoOOH, and Co3O4, and the n-type semiconducting oxide ZnO. These materials can all be electrodeposited as epitaxial films or nanostructures onto single-crystal surfaces. Examples of epitaxial growth are given for the growth of films of CuI(111) on Si(111) and nanowires of CuSCN(001) on Au(111). Both are large mismatch systems, and the epitaxy is explained by invoking coincidence site lattices in which x unit meshes of the film overlap with y unit meshes of the substrate. We also discuss the epitaxial lift-off of single-crystal-like foils of metals such as Au(111) and Cu(100) that can be used as flexible substrates for the epitaxial growth of semiconductors. The metals are grown on a Si wafer with a sacrificial SiOx interlayer that can be removed by chemical etching. The goal is to move beyond the planar structure of conventional Si-based chips to produce flexible electronic devices such as wearable solar cells, sensors, and flexible displays. A scheme is shown for the epitaxial lift-off of wafer-scale foils of the transparent hole conductor CuSCN. Finally, we offer some perspectives on possible future work in this area. One question we have not answered in our previous work is whether these epitaxial films and nanostructures can be grown with the level of perfection that is achieved in UHV. Another area that is ripe for exploration is the epitaxial electrodeposition of metal-organic framework materials from solution precursors

Scanning Probe Nanolithography of Conducting Metal Oxides

The scanning tunneling microscope (STM) was used to form nanometer-size holes in thin conducting films of thallium (III) oxide. Hole formation was only observed when the process was performed in humid ambient conditions. The hole formation was attributed to localized electrochemical etching reactions beneath the STM tip. etching reactions consistent with the observed hole formation are a direct electrochemical reduction of thallium (III) oxide to soluble T1 (I) at negative sample bias, and local reduction of pH at positive sample bias. The fastest etching was observed at negative sample bias. Holes as small as 10 nm or as large as 1 μm in diameter could be etched in the films

Composition Profiles in Electrodeposited Ceramic Superlattices

Superlattices in the Pb-Tl-O system with layer thicknesses in the 4-6 nm range were electrodeposited from a single aqueous solution by pulsing the applied potential during deposition. The current-time transients that resulted from the potential steps were monitored to both calculate and tailor the composition profiles of the superlattices during growth. The Cottrell method was used to determine that Tl(l) oxidation was diffusion limited at high potentials. The diffusion limitation resulted in a composition profile that was graded throughout the layer with a t-1/2 dependence. Superlattices grown at lower potentials in which both reactants were under kinetic control had square composition profiles

Epitaxial Electrodeposition of Hole Transport CuSCN Nanorods on Au(111) at the Wafer Scale and Lift-Off to Produce Flexible and Transparent Foils

The wide bandgap p-type metal pseudohalide semiconductor copper(I) thiocyanate (CuSCN) can serve as a transparent hole transport layer in various opto-electronic applications such as perovsksite and organic solar cells and light-emitting diodes. The material deposits as one-dimensional CuSCN nanorod arrays, which are advantageous due to their high surface area and good charge transport properties. However, the growth of high-quality epitaxial CuSCN nanorods has remained a challenge. Here, we introduce a low cost and highly scalable room temperature procedure for producing epitaxial CuSCN nanorods on Au(111) by an electrochemical method. Epitaxial CuSCN grows on Au(111) with a high degree of in-plane as well as out-of-plane order with +0.22% coincidence site lattice mismatch. The phase of CuSCN that deposits is a function of the Cu2+/SCN- ratio in the deposition bath. A pure rhombohedral material deposits at higher SCN- concentrations, whereas a mixture of rhombohedral and hexagonal phases deposits at lower SCN- concentrations. A Au/epitaxial CuSCN/Ag diode has a diode quality factor of 1.4, whereas a diode produced with polycrystalline CuSCN has a diode quality factor of 2.1. A highly ordered foil of CuSCN was produced by epitaxial lift-off following a triiodide etch of the thin Au substrate. The 400 nm-thick CuSCN foil had an average 94% transmittance in the visible range and a 3.85 eV direct bandgap

Method of Preparing a Chiral Substrate Surface By Electrodeposition

A solid substrate comprising a surface comprising an achiral array of atoms having thereupon a chiral metal oxide surface. The chiral metal oxide surface is prepared by electrodeposition of a chiral metal oxide array from a solution of a chiral salt of the metal. In one embodiment, chiral CuO is grown on achiral Au(001) by epitaxial electrodeposition. The handedness of the film is determined by the specific enantiomer of tartrate ion in the deposition solution. (R,R)- tartrate produces an S—CuO(l 1 T) film, while (S,S)-tartrate produces an R—CuO(Tl 1) film. These chiral CuO films are enantiospecific for the electrochemical oxidation of(R,R) and (S,S)-tartrate

Room-Temperature Electrochemical Reduction of Epitaxial Bi₂O₃ Films to Epitaxial Bi Films

This work reports a new facile approach to fabricate high-quality epitaxial Bi thin films by direct electrochemical reduction of epitaxial δ-Bi2O3 thin films on Au single crystals in aqueous solution at room-temperature. The as-produced Bi thin films (without any post-annealing process) exhibit large grain sizes, continuous microstructures, and enhanced magnetotransport properties

Rakennusautomaation vastaanoton kehittäminen

Rakennusautomaation vastaanotto ja siihen liittyvät toimintakokeet ovat keskeisiä vaiheita rakennusautomaatioprojektin laadun varmennuksessa. Senaatti-kiinteistöjen talotekniikan asiantuntija Timo Keskikuru oli havainnut koko alaa koskevia puutteita vastaanottoprosessissa ja toivoi asiaa tutkittavan. Työn tavoitteena oli kehittää rakennusautomaation vastaanoton toimintatapoja. Työssä selvitettiin aiheeseen liittyviä säännöksiä ja toimintatapoja kirjallisista lähteistä. Kehitystyön kannalta tärkein tutkimismenetelmä oli alan eri toimijoiden haastattelut. Käytännön kokemuksia saatiin pilottikohteesta, jossa kehitystyön tuloksia testattiin. Työssä kehitettiin vastaanoton tueksi myös tarkastusdokumentointia. Vastaanoton kehittämistarpeet nousivat työn aikana selvästi esille. Dokumentoinnin kehittämiseen on tulevaisuudessa varattava lisää resursseja, jotta laajempi uudistus vallitseviin käytäntöihin olisi mahdollinen. Myös vastaanoton toimintatapojen uudistaminen koko rakennusautomaatioalalla vaatii loppuun asti kehitettyjä ohjeistuksia ja valmiita dokumentteja, jotka myös otetaan käyttöön.Acceptance of building automation and functional test are important subjects when developing building automation system projects. Timo Keskikuru, Expert in Building Services Engineering in Senaatti-Kiinteistöt, had noticed some deficiencies in the acceptance procedure and wanted a research to be done. The goal was to a develop procedure for building automation acceptance. In the execution rules and working policies were studied from literature of the field. The most important way of research was interviews of professionals from different perspectives. Practical experience was gathered in a pilot project, which gave an opportunity to test some results of the development. As a result, a documentation was developed to support acceptance. The need of development in acceptance was clear. More resources must be given to research and development of documentation to reform the procedure more. Also documents and instructions must be properly improved and finished to make difference in larger scale

Electrochemical Deposition and Characterization of Fe₃O₄ Films Produced by the Reduction of Fe(III)-triethanolamine

In this paper, we demonstrate that films of magnetite, Fe3O4, can be deposited by the electrochemical reduction of a Fe(III)-triethanolamine complex in aqueous alkaline solution. the films were deposited with a columnar microstructure and a [100] preferred orientation on stainless steel substrates. In-plane electrical transport and magnetoresistance measurements were performed on the films after they were stripped off onto glass substrates. the resistance of the films was dependent on the oxygen partial pressure. We attribute the increase in resistance in O2 and the decrease in resistance in Ar to the oxidation and reduction of grain boundaries. the decrease in resistance in an Ar atmosphere exhibited first-order kinetics, with an activation energy of 0.2 eV. the temperature dependence of the resistance showed a linear dependence of log(R) versus T-1/2, consistent with tunneling across resistive grain boundaries. a room-temperature magnetoresistance of -6.5% was observed at a magnetic field of 9 T