Chemical vapour deposition and atomic layer deposition of amorphous and nanocrystalline metallic coatings: towards deposition of multimetallic films

This paper provides a prospective insight on chemical vapour deposition (CVD) and atomic layer deposition (ALD) as dry techniques for the processing of amorphous and nanocrystalline metallic thin films. These techniques are part of major technologies in application fields such as microelectronics, energy, or protective coatings. From thermodynamic analysis, areas of investigation to generate a set of materials with the strongest propensity for amorphization as well as useful guidelines for the target phase material deposition are provided. Prospective to develop MOCVD (metalorganic chemical vapour deposition) and ALD of intermetallic films, in view of fabrication of metallic glass thin films is proposed. Examples from selected ALD and MOCVD single element metallic deposition processes will be described to illustrate the effect of deposition parameters on the physico-chemical properties of the films. This processing approach is particularly promising for metallic glass thin films

Synthetic Graphene Grown by Chemical Vapor Deposition on Copper Foils

The discovery of graphene, a single layer of covalently bonded carbon atoms, has attracted intense interests. Initial studies using mechanically exfoliated graphene unveiled its remarkable electronic, mechanical and thermal properties. There has been a growing need and rapid development in large-area deposition of graphene film and its applications. Chemical vapour deposition on copper has emerged as one of the most promising methods in obtaining large-scale graphene films with quality comparable to exfoliated graphene. In this chapter, we review the synthesis and characterizations of graphene grown on copper foil substrates by atmospheric pressure chemical vapour deposition. We also discuss potential applications of such large scale synthetic graphene.Comment: 23 pages, 4 figure

Modified CVD of nanoscale structures in and EVD of thin layers on porous ceramic membranes

Experiments on the modified chemical vapour deposition (CVD) and the electrochemical vapour deposition (EVD) of yttria-stabilized zirconia on porous substrates are reported. It is shown that, in the CVD stage, deposition occurs in a small (<20 um) region at the edge of the substrate, very likely leading to pore narrowing. This result illustrates the feasibility of the CVD technique for the modification of ceramic membranes to the (sub)nanometer scale. Film growth in the EVD stage is shown to be controlled by the inpore diffusion of the oxygen source reactant for short (<5 h) deposition times. The yttria to zirconia ratio in the deposited film is determined by the ratio present in the vapour phase. Very thin (<2 um) films can be deposited, which have a potential application in solid oxide fuel cells

Modelling and analysis of CVD processes for ceramic membrane preparation

A mathematical model is presented that describes the modified chemical vapour deposition (CVD) process (which takes place in advance of the electrochemical vapour deposition (EVD) process) to deposit ZrO2 inside porous media for the preparation and modification of ceramic membranes. The isobaric model takes into account intrapore Knudsen diffusion of ZrCl4 and H2O, which enter the membrane from opposite sides, and Langmuir-Hinshelwood reaction of the solid product ZrO2 on the internal pore wall. The processes occurring in one single pore are investigated, and the change in pore geometry during deposition is taken into account. Based upon this model, the deposition profile is studied. The model fits reasonably well with experimental results

A study of drop-coated and chemical bath-deposited buffer layers for vapour phase deposition of large area, aligned, zinc oxide nanorod arrays

Zinc oxide films derived from drop-coating solutions of zinc acetate in ethanol followed by chemical bath deposition were examined for their suitability as buffer layers for high temperature vapour phase deposition of large area, aligned, zinc oxide nanorod arrays. An XPS analysis of substrates drop coated with zinc acetate solutions clarifies the chemistry of the deposition mechanism of the initial acetate-derived ZnO seeds. SEM, AFM and white light profilometry studies show that while zinc acetate-derived buffer layers are suitable for chemical bath deposition of aligned zinc oxide nanorod arrays, during high temperature vapour phase depositions these buffer layers undergo substantial changes leading to a loss of nanorod alignment and poor substrate coverage. We present a method to deposit aligned zinc oxide nanorod arrays uniformly over large area substrates, which combines zinc acetate drop coating, chemical bath deposition of buffer layers and vapour phase transport deposition of nanorods

Mass spectrometry as a tool study CVD process

Mass spectrometry as a tool study CVD process. Application of two mass spectrometric (MS) techniques to study chemical vapour deposition from organometallic precursors is described. CpCuPEt3 (Cp = η5-C5H5, Et =C2H5) was used as a model precursor in this work

Low pressure chemical vapour deposition at quasi-high flow

A new chemical vapour deposition (CVD) technique is presented. It is especially advantageous for the deposition of compound materials. The technique improves the uniformity and reproducibility of the deposition. The economical use of gaseous reactants is improved by a factor varying between 5 and 20. This is important in the case of expensive metal-organic CVD methods. The method consists in the manifold repetition of the following sequence: evacuation, filling and deposition in a horizontal tube reactor. The filling time of 50 ms is short compared with the deposition period 1 s.\ud \ud The advantages of the method are demostrated with results for the deposition of undoped, phosphorus-doped and boron-doped silicon and SiO2.\u

Metal free graphene synthesis on insulating or semiconducting substrates

The present invention relates to a process for preparing graphene by chemical vapour deposition (CVD), wherein an insulating or semiconducting inorganic substrate is provided in a chemical vapour deposition (CVD) reactor and subjected to a thermal pre-treatment in a hydrogen-containing atmosphere,and graphene is deposited on the inorganic substrate by bringing a gaseous oxidant and a carbon-containing precursor into contact with the inorganic substrate