Plasma-assisted Deposition Method Research Articles

Femtosecond laser-induced plasma-assisted backward deposition of robustly adherent porous carbon films on glass substrates

The simple and rapid production and transfer of high-quality carbon materials are crucial for the flexible and efficient fabrication of carbon-based electronic devices. Recently, a laser-assisted transfer method combining laser-induced carbonization and transfer printing was demonstrated for the one-step preparation and transfer of patterned laser-induced carbon films to transparent substrates. However, this method is limited by insufficient robustness and weak adhesion of the carbon film post-transfer. Herein, we developed a non-contact laser-induced plasma-assisted deposition method to deposit robustly adherent porous carbon films on glass substrates. By well-adjusting the laser parameters and inserting spacers with adjustable thickness, laser-induced plasma ablation replaced direct laser ablation during femtosecond laser scanning of the substrate-polyimide-carrier sandwich structure, resulting in micro-channels with a carbon-glass recast layer instead of easily peelable flakes on the glass substrate. This hierarchical structure significantly enhances the adhesion between the laser-induced carbon film and the glass substrate, ensuring outstanding stability of the deposited carbon film under various adhesion tests. Furthermore, compared to carbon films prepared by the laser-assisted transfer method, the obtained carbon films are hydrophilic, low-resistance, and porous, facilitating the fabrication of energy storage devices. To demonstrate its practical application, a planar carbon-based micro-supercapacitor was fabricated on glass, exhibiting excellent electrochemical and cycling performance.

A Novel Approach towards the Preparation of Silk-Fibroin-Modified Polyethylene Terephthalate with High Hydrophilicity and Stability

Silk fibroin (SF) has been widely used in biomedical applications for the hydrophilicity modification of high molecular polymer materials. However, the challenge remains to immobilize SF with high structure stability and strong adhesion strength between SF and the substrate. Here, we propose an effective two-step process for modifying polyethylene terephthalate (PET) with SF: dipping PET film in SF solution and subsequently carrying out plasma-assisted deposition in SF aerosol. The structure and property analysis revealed that the SF-modified PET (PET-SF) prepared using the two-step method exhibited superior structural stability and stronger adhesion strength compared to the dip-coating method and the plasma-assisted deposition method. In addition, PET-SF prepared using the two-step method resulted in a higher concentration of SF and an increased content of active groups on its surface, enhancing its hydrophilicity compared to the other two methods. Additionally, the influence of dipping time and deposition time in the two-step method was investigated. The results demonstrated that the dipping time for 6 h and the deposition time for 3 min resulted in maximum SF grafting amount with a highly stable structure. Furthermore, the PET-SF exhibited satisfactory hydrophilicity when the deposition time was more than 3 min and showed the most hydrophilicity surface at 8 min.

Structure and Properties of CrN/TiN Multi-Layer Coatings Obtained by Vacuum-Arc Plasma-Assisted Deposition Method

The paper presents the study results of CrN/TiN multi-layer coatings, as well as single-layer TiN and CrN coatings on Cr12MoV cold work die steel deposited by the vacuum-arc plasma-assisted method. Three CrN/TiN coatings of 8-, 16-, and 32-layers were deposited, in which the thickness of each layer was 500 nm, 250 nm and 125 nm, respectively. All of the coatings reveal a face-centered cubic structure with highly oriented (111) growth. The hardness of the CrN/TiN multi-layer coatings was about 27 GPa. Changing the architecture of CrN/TiN multi-layer coatings by reducing the thickness of the CrN and TiN layers from 500 nm to 125 nm promotes a smooth decrease in both the wear parameter and the coefficient of friction. By using an X-ray phase analysis with synchrotron radiation, it was found that 32-layer CrN/TiN coating retained thermal stability during heating in air to a temperature of 1120–1125 °C, and in a vacuum at least to a temperature of 1200 °C.

A review of plasma-assisted deposition methods for amorphous carbon thin and ultrathin films with a focus on the cathodic vacuum arc technique

A review of plasma-assisted deposition methods for amorphous carbon thin and ultrathin films with a focus on the cathodic vacuum arc technique

Substituted Hydroxyapatite, Glass, and Glass-Ceramic Thin Films Deposited by Nanosecond Pulsed Laser Deposition (PLD) for Biomedical Applications: A Systematic Review

The deposition of thin films of bioactive materials is the most common approach to improve the bone bonding ability of an implant surface. With this purpose, several wet and plasma assisted deposition methods were proposed in the scientific literature. In this review, we considered films obtained by nanosecond Pulsed Laser Deposition (PLD). Since hydroxyapatite (HA) has composition and structure similar to that of the mineral component of the bone, the initial studies focused on the selection of experimental conditions that would allow the deposition of films that retain HA stoichiometry and crystallinity. However, biological apatite was found to be a poorly crystalline and multi-substituted mineral; consequently, the attention of researchers was oriented towards the deposition of substituted HA, glass (BG), and glass-ceramic (BGC) bioactive materials to exploit the biological relevance of foreign ions and crystallinity. In this work, after a description of the nanosecond ablation and film growth of ceramic materials, we reported studies on the mechanism of HA ablation and deposition, evidencing the peculiarities of PLD. The literature concerning the PLD of ion substituted HA, BG, and BGC was then reviewed and the performances of the coatings were discussed. We concluded by describing the advantages, limitations, and perspectives of PLD for biomedical applications.

Formation of polymer-based nanoparticles and nanocomposites by plasma-assisted deposition methods

During the last decades, metal-polymer nanocomposites have been subject to extensive research as their electrical, magnetic and optical properties are very sensitive to their specific compositions and morphological structures. Although there exist a variety of standardized and well-established production processes based on plasma-assisted physical vapor deposition methods, significant progress in the understanding of the self-organized formation process has only been achieved with the help of computer simulations. In particular, computational approaches based on kinetic Monte Carlo (KMC) and molecular dynamics (MD) simulations turned out to be successful in recent years because they offer the potential to simulate and predict the system behavior on sufficiently long time scales. In this paper, we review several formation processes of metal-polymer systems that have been investigated in joint experimental and theoretical KMC and MD studies. These comprise the growth of metallic nanocolumns in a polymer matrix and the growth of nanogranular structures on a polymer film.

Anti-biofouling and antibacterial surfaces via a multicomponent coating deposited from an up-scalable atmospheric-pressure plasma-assisted CVD process.

Prevention of bacterial adhesion and biofilm formation on the surfaces of materials is a topic of major medical and societal importance. In this study, an up-scalable atmospheric-pressure plasma assisted deposition method is introduced to produce a multicomponent coating towards the elaboration of antibacterial and anti-biofilm surfaces. Interestingly, from a single catechol-based monomer, high deposition rates of highly chemically reactive functional thin films bearing catechol as well as quinone groups are achieved. The catechol-bearing thin film allows the in situ silver nanoparticle formation, assessed by scanning electron microscopy and EDX, whilst the enriched-quinone thin film is exploited for immobilizing dispersine B, an enzyme. In vitro functional assays demonstrated the dual antibacterial and anti-biofouling resistance properties of the coatings due to the antibacterial effect of silver and the fouling resistance of grafted dispersine B, respectively. Surfaces coated only with silver provide an antibacterial effect but fail to inhibit bacterial attachment, highlighting the usefulness of such dual-action surfaces. The approach presented here provides a simple and effective chemical pathway to construct powerful antibacterial surfaces for various industrial applications.

Shaping thin film growth and microstructure pathways via plasma and deposition energy: a detailed theoretical, computational and experimental analysis.

Understanding the science and engineering of thin films using plasma assisted deposition methods with controlled growth and microstructure is a key issue in modern nanotechnology, impacting both fundamental research and technological applications. Different plasma parameters like electrons, ions, radical species and neutrals play a critical role in nucleation and growth and the corresponding film microstructure as well as plasma-induced surface chemistry. The film microstructure is also closely associated with deposition energy which is controlled by electrons, ions, radical species and activated neutrals. The integrated studies on the fundamental physical properties that govern the plasmas seek to determine their structure and modification capabilities under specific experimental conditions. There is a requirement for identification, determination, and quantification of the surface activity of the species in the plasma. Here, we report a detailed study of hydrogenated amorphous and crystalline silicon (c-Si:H) processes to investigate the evolution of plasma parameters using a theoretical model. The deposition processes undertaken using a plasma enhanced chemical vapor deposition method are characterized by a reactive mixture of hydrogen and silane. Later, various contributions of energy fluxes on the substrate are considered and modeled to investigate their role in the growth of the microstructure of the deposited film. Numerous plasma diagnostic tools are used to compare the experimental data with the theoretical results. The film growth and microstructure are evaluated in light of deposition energy flux under different operating conditions.

Epitaxial growth of single-domain graphene on hexagonal boron nitride

Hexagonal boron nitride (h-BN) has recently emerged as an excellent substrate for graphene nanodevices, owing to its atomically flat surface and its potential to engineer graphene's electronic structure. Thus far, graphene/h-BN heterostructures have been obtained only through a transfer process, which introduces structural uncertainties due to the random stacking between graphene and h-BN substrate. Here we report the epitaxial growth of single-domain graphene on h-BN by a plasma-assisted deposition method. Large-area graphene single crystals were successfully grown for the first time on h-BN with a fixed stacking orientation. A two-dimensional (2D) superlattice of trigonal moiré pattern was observed on graphene by atomic force microscopy. Extra sets of Dirac points are produced as a result of the trigonal superlattice potential and the quantum Hall effect is observed with the 2D-superlattice-related feature developed in the fan diagram of longitudinal and Hall resistance, and the Dirac fermion physics near the original Dirac point is unperturbed. The macroscopic epitaxial graphene is in principle limited only by the size of the h-BN substrate and our synthesis method is potentially applicable on other flat surfaces. Our growth approach could thus open new ways of graphene band engineering through epitaxy on different substrates.

Influence de la température de substrat sur la croissance et les propriétés des films minces de silicium amorphe déposés par pulvérisation cathodique

We deposit thin films of a-Si:H by RF diode spray on substrate with temperatures varying from 200 to 500 °C. Knowing that this deposition method is violent when compared with the plasma-assisted deposition method, we have used low RF power to limit the energy of the Ar ions bombarding the surface of the growing film. Characterization of the films by UV–visible absorption spectroscopy suggests that the influence of the substrate temperature can be classified into three different regimes: (i) low temperature, Ts < 300 °C: the films show a strong disorder, the hydrogen is bound only in the polyhydric configuration; (ii) intermediate temperature, 300 °C < Ts < 400 °C: film growth is rapid, the films present a lower defect density; this may be the best regime to make good quality a-Si:H films using the spraying method; (iii) high temperature, Ts > 400 °C: the films are more organized, but less hydrogenated. The substrate temperature influences the film properties by modifying the growing mechanism through a control of the reactions taking place at the plasma–substrate interface, where the hydrogen dynamics play a fundamental role.[Journal translation]

High Intensity Radical Beam Source ad Thin Film Synthesis.

Plasma assisted deposition methods have been widely used so far to synthesize varieties of thin films. However, charged particles such as electrons and ions, which are inevitably included in plasma, hit surfaces of thin film while the films are being deposited and deteriorate the characteristics of the films. In this article we first describe our results concerning titanium oxides deposition by a “pulsed beam deposition method” and show that active oxygen species are necessary to synthesize completely oxidized titanium oxide thin films. Subsequently, we introduce a high intensity radical beam source which does not emit charged particles and its performance with a review of radical beam sources and methods to determine the intensity of radical beam. Finally, we conclude with some examples of the application of the radical beam source to the synthesis of ceramic films.

Plasma-assisted deposition at atmospheric pressure

Most plasma-assisted deposition methods currently available use gas discharges at pressures below 1 hPa. In many cases, the process temperature can be kept low due to the fact that the energy necessary for the initiation of chemical reactions is transferred via charged particles. However, a low pressure requires a large amount of vacuum equipment. Processes at atmospheric pressure are more favourable if results similar to those of existing methods can be achieved. Barrier discharges provide the basis for a new plasma-assisted deposition method at atmospheric pressure. These discharges consist of a large number of transient microdischarges in parallel which are distributed statistically on the surface to be coated. Starting with some basic considerations on the properties of microdischarges, the deposition of thin polymeric films on glass surfaces is described using barrier discharges at atmospheric pressure and acetylene. Uniform polymeric films up to 1 μm are obtained if trains of voltage pulses are used. The parameters influencing the deposition rate and the film quality are discussed. In addition, it is estimated whether further improvements of the deposition process are possible.

Plasma-Assisted Deposition at Atmospheric Pressure

In plasma-assisted deposition methods the activation energy necessary for the initiation of chemical reactions is transferred via charged particles. Due to this fact in many cases the process temperature can be kept small, if gas discharges at pressures below 1 hPa are used. On the other hand low pressure requires a great deal of vacuum equipment. Processes at atmospheric pressure are more favourable, if similar results compared to existing methods can be achieved. Basis for a new plasma-assisted deposition method at atmospheric pressure are barrier discharges. Those discharges consist of a large number of transient microdischarges in parallel which are distributed statistically on the surface to be coated. Starting with some basic considerations on the repetitive generation of microdischarges, the deposition of thin polymeric films on glass surfaces is described, using barrier discharges at atmospheric pressure and acetylene. Uniform polymeric films up to 1 μm are obtained, if trains of voltage pulses are used. Parameters influencing the deposition rate and the film quality are discussed. In addition, it is estimated whether further improvements of the deposition process are possible.

GaN films prepared by ECR plasma-assisted deposition

An electron cyclotron resonance plasma-assisted deposition method has been used polycrystalline GaN films. These GaN films can have dark conductivities as low as 10 −10 S cm −1 and they exhibit well-defined conductivity activation energies. The sample conductivity is decreased by surface adsorption of gases and it increases again when the adsorbed species is photodesorbed from the surface using UV light. As a result, the photoresponse is very slow, especially the decay process, which may require several days for a sample to recover when it is mounted in a vacuum. This recovery time can be reduced significantly if the sample temperature is increased or the sample is exposed to air. In this respect, these GaN films have a number of features in common with ZnO.