Fast and non-catalytic growth of transparent and conductive graphene-like carbon films on glass at low temperature

This article presents the synthesis and systematic study of graphene-like carbon thin films directly grown on commercial glass by using remote electron cyclotron resonance plasma-assisted chemical vapour deposition. The fabrication process is extremely rapid and performed on 2 inch scale dielectric substrate at relatively low temperature (<550 °C) without using metal catalyst. This method avoids damaging and expensive transfer processes of graphene based films and improves compatibility with current fabrication technologies. Nanostructural characterization by transmission electron microscopy indicates the formation of layered graphene-like carbon material. Raman spectroscopy shows that the film consists of nanocrystals with a mean domain size close to 2 nm, probably interconnected by amorphous material. These graphene-like carbon based films are transparent and conductive. Functional optoelectric characterization of these films confirms their high transparency over 95% and relative high conductivity around 5 kΩ, exceeding the properties of non-doped small domain graphene based films grown at low temperatures reported so far. © 2014 IOP Publishing Ltd.The authors appreciate the financial support of the Consolider-Ingenio project (CSD2008-00023), funded by the Spanish Ministry of Science and Innovation (MICINN). Also, the research leading to these results has received funding from the European Union Seventh Framework Programme under grant agreement nº604391 Graphene Flagship.Peer Reviewe

Effect of argon on the deposition of ECR-CVD hydrogenated carbon nitride films

[ES] Se ha estudiado el efecto del argon durante el proceso de CVD asistido por un plasma ECR para la síntesis de películas de nitruro de carbono (CNxHy) a partir de mezclas gaseosas Ar/CH4/N2 con diferente contenido de metano. Las películas depositadas han sido analizadas mediante espectroscopía infrarroja (IRS) y ERDA (Elastic Recoil Detection Analysis), y el análisis del plasma ha sido realizado utilizando la técnica de espectroscopía de emisión óptica (OES). La velocidad de deposición y la composición de las películas depositadas se encuentran determinadas por la concentración de argon en la mezcla gaseosa. Se propone un modelo, según el cual el argon juega un papel fundamental como activador de las moléculas de metano. El modelo propuesto incluye dos procesos simultáneos durante el crecimiento de las capas : i) formación de la capa y ii) ataque de la superficie de crecimiento. Según la composición de la mezcla gaseosa se favorece uno u otro proceso, lo que conduce a velocidades de deposición diferentes así como a depósitos con diferente composición y estructura atómica.[EN] Carbon nitride films have been deposited by ECR-CVD, from Ar/CH4/N2 gas mixtures with different methane concentrations. Infrared Spectroscopy (IRS) and Elastic Recoil Detection Analysis (ERDA) have been used for films characterisation and Optical Emission Spectroscopy (OES) for plasma analysis. Argon concentration in the gas mixture controls the growth rate as well as the composition of the film. In the proposed model, argon plays a key role in the activation of methane molecules. Also, during the growth of the film, two processes may be considered: i) Film formation and ii) Etching of the growing surface. Changing the gas mixture composition affects both processes, which results in films with different composition and structure as well as different deposition rates.Los autores agradecen a la Comunidad de Madrid (Proyecto 07N/0027/2001) y a la Comunidad Económica Europea (Proyecto 2FD97-1574-C02-02 (MAT)) la ayuda recibida para la financiación de este trabajo. Así mismo, quieren agradecer al Dr. U. Kreissig su ayuda en la caracterización por ERDA de las muestras estudiadas. Uno de los autores (M.C.) agradece al CSIC (Beca I3P-BPD2001-1) la ayuda recibida.Peer reviewe

Materiales y técnicas de fase vapor para la síntesis de recubrimientos cerámicos

[ES] Se hace un descripción de los avances recientes en la síntesis de recubrimientos duros de tipo cerámico, depositados mediante técnicas de deposición en fase vapor. Se dedica especial atención a los parámetros del proceso de deposición que controlan las propiedades finales de las capas (estructura cristalina, morfología, etc), tales como la energía de llegada de los átomos a las superficie en crecimiento, y la temperatura. Finalmente, se hace una revisión de los materiales más relevantes en lo que se refiere a sus aplicaciones como recubrimientos duros y protectores, o como recubrimientos decorativos, entre ellos, la familia de los nitruros, carburos y óxidos metálicos, depositados en diversos tipos de estructuras (monolíticas, multicapas y nanocomposites), y los compuestos ternarios del sistema BCN.[EN] A survey on recent advances in the synthesis of hard ceramic coatings is given, including materials processes and techniques. Emphasis is made on the parameters which control the coating properties (crystalline structure, morphology, etc), namely arrival energy of the atoms to the growing surface and substrate temperature. Some relevant coating materials are discussed in relation to their applications either as hard protective coatings or with decorative purposes, namely: the family of metal nitrides, carbides, and oxides, in different layer structures (monolithic, multilayers and nanocomposites) and ternary compounds of the BCN system.Peer reviewe

Low temperature metal free growth of graphene on insulating substrates by plasma assisted chemical vapor deposition

Direct growth of graphene films on dielectric substrates (quartz and silica) is reported, by means of remote electron cyclotron resonance plasma assisted chemical vapor deposition r-(ECR-CVD) at low temperature (650 °C). Using a two step deposition process– nucleation and growth– by changing the partial pressure of the gas precursors at constant temperature, mostly monolayer continuous films, with grain sizes up to 500 nm are grown, exhibiting transmittance larger than 92% and sheet resistance as low as 900 Ω sq−1. The grain size and nucleation density of the resulting graphene sheets can be controlled varying the deposition time and pressure. In additon, first-principles DFT-based calculations have been carried out in order to rationalize the oxygen reduction in the quartz surface experimentally observed. This method is easily scalable and avoids damaging and expensive transfer steps of graphene films, improving compatibility with current fabrication technologies.This work has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 696656. JA acknowledges funding from FPI Program of MINECO (BES-2012-058600). JIM acknowledges funding from the ERC-Synergy Program (Grant ERC-2013-SYG-610256 NANOCOSMOS) and computing resources from CTI-CSIC. CM acknowledges the financial support by the 'Ramón y Cajal' Program of MINECO (RYC-2014-16626).Peer reviewe

Removal of carbon films by oxidation in narrow gaps: Thermo-oxidation and plasma-assisted studies

5 pages, 6 figures.-- PACS nrs.: 28.52.Fa; 52.40.Hf; 52.77.Bn; 68.60.Dv.The removal of hard amorphous hydrogenated carbon (a-C: H) films from narrow gaps simulating the macro-brush structures present in controlled fusion devices has been investigated. Films with thickness of 50-150 nm were generated through plasma assisted chemical vapor deposition (PACVD) in glow discharges of CH4/He on Si and stainless steel plates. The deposited plates were then arranged to form sandwich structures building narrow gaps and were subject to erosion by exposure to O2/He plasmas and to thermal oxidation by O2 and by a NO2/N2 (1:1) mixture. In the plasma etching experiments, the deposited layers were only partially removed by the plasma at the side wall gap surfaces, but were efficiently removed at the bottom of the gap. In the thermo-oxidation experiments, the deposited films were effectively and homogeneously removed with oxigen at 670 K and with the NO2/N2 mixture at T > 570 K.This work has been funded by EFDA under the Technical Task, TW6-TPP-Gapox; and by the MEC of Spain under grants FIS2007-61686 and ENE2006-14577-CO4-CO3/FTN.Peer reviewe

Deposición de capas de grafeno mediante deposición química en fase vapor asistida por plasma

The invention relates to a method for depositing high-quality graphene layers on a substrate by means of plasma-enhanced chemical vapour deposition, said graphene layers comprising nanocrystals of sizes that can be controlled with temperature and time and which are interconnected by amorphous phase. The invention also relates to said material deposited on a substrate and the use thereof as a component in touch panels or touch windows, protection systems, electrodes, hard disc read heads/platters, as a resistant coating, and as a component of a resistance heater.Consejo Superior de Investigaciones Científicas (España)A1 Solicitud de patente con informe sobre el estado de la técnic

Deposición de capas de grafeno mediante deposición química en fase vapor asistida por plasma

[EN] The invention relates to a method for depositing high-quality graphene layers on a substrate by means of plasma-enhanced chemical vapour deposition, said graphene layers comprising nanocrystals of sizes that can be controlled with temperature and time and which are interconnected by amorphous phase. The invention also relates to said material deposited on a substrate and the use thereof as a component in touch panels or touch windows, protection systems, electrodes, hard disc read heads/platters, as a resistant coating, and as a component of a resistance heater.[ES] La invención se refiere a un procedimiento de deposición de capas de grafeno de alta calidad sobre un sustrato que se realiza mediante deposición química en fase vapor asistida por plasma, comprendiendo dichas capas de grafeno nanocristales de tamaños controlables con la temperatura y el tiempo interconectados por fase amorfa. Además, la invención se refiere a dicho material depositado sobre un sustrato y su uso como componente de ventanas o paneles táctiles, sistemas de protección, electrodos, elemento de cabezas lectoras/platos de disco duro, como recubrimiento resistente y como componente de un calefactor o calentador resistivo.Peer reviewedConsejo Superior de Investigaciones Científicas (España)A1 Solicitud de patente con informe sobre el estado de la técnic

Deposition of graphene layers by means of plasma-enhanced chemical vapour deposition

La invención se refiere a un procedimiento de deposición de capas de grafeno de alta calidad sobre un sustrato que se realiza mediante deposición química en fase vapor asistida por plasma, comprendiendo dichas capas de grafeno nanocristales de tamaños controlables con la temperatura y el tiempo interconectados por fase amorfa. Además, la invención se refiere a dicho material depositado sobre un sustrato y su uso como componente de ventanas o paneles táctiles, sistemas de protección, electrodos, elemento de cabezas lectoras/platos de disco duro.Peer reviewedConsejo Superior de Investigaciones Científicas (España)A1 Solicitud de patente con informe sobre el estado de la técnic

Spectroscopic measurements of the electron temperature in low pressure radiofrequency Ar/H2/C2H2 and Ar/H2/CH4 plasmas used for the synthesis of nanocarbon structures

[Full text not available yet]This paper deals with optical emission spectroscopy studies of low pressure (0.1–0.5 Torr) capacitively coupled radiofrequency hydrocarbon/argon-rich plasmas used for the synthesis of nanocarbon structures. The main goal of this paper is to obtain the electron temperature of such far-from-equilibrium plasmas as a function of the pressure, the excitation power and the argon content. In doing so, we have found that the argon upper energy levels used for electron temperature estimation remain close to corona balance. The latter has allowed us to use a modified Boltzmann plot technique to derive the electron temperature. It was found that, for the plasmas investigated, an increase of the argon population density (from 10% to 95%) leads to a pronounced decrease of the electron temperature while an increase of the processing pressure produces a moderate increase of the electron temperature. Additionally, the increase of the power from 50 to 300W produces a very slight growth of the electron temperature.This work has been partially financed by the Spanish National Project (MAT2002-04085-C02-02). One of the authors (MC) is indebted to CSIC (Consejo Superior de Investigaciones Científicas) for financial help.Peer reviewe