Effect Of Deposition Temperature Research Articles

Effect of deposition temperature on the microstructure and tribological properties of Si-DLC coatings prepared by PECVD

The tribological properties of diamond-like carbon (DLC) coatings were influenced by their microstructure, which was controlled by the preparation technology and parameters. In this study, Si-DLC coatings were prepared on cemented carbide (YG10C) and stainless steel (316L) substrates by plasma enhanced chemical vapor deposition with various deposition temperatures. The effect of the deposition temperature on the microstructure and tribological properties was systematically investigated. The results showed that the sp3/sp2 values and hardness of the Si-DLC coatings increased firstly and then decreased as the deposition temperature increased from 60 °C to 180 °C, while the tendency in toughness, adhesion strength and residual stress is not consistent with it. The performance of the coatings obtained at 120 °C was best, while the coatings obtained at 150 °C had the lowest toughness due to the volume expansion caused by the transformation of sp3 to sp2. A graphite transfer layer was observed on the wear tracks of friction pairs. Thereinto, O-Si-C on the transfer layer could further reducing shear resistance and plays a role as a lubricant. Therefore, the coating prepared at the preferred deposition temperature had excellent tribological properties.

Effect of Deposition Temperature on the Evolution of Texture, Grain Boundary Constitution and Corrosion Behaviour of Sn–Cr Coatings

Effect of Deposition Temperature on the Evolution of Texture, Grain Boundary Constitution and Corrosion Behaviour of Sn–Cr Coatings

Thermally Driven Structural Order of Oligo(Ethylene Glycol)-Terminated Alkanethiol Monolayers on Au(111) Prepared by Vapor Deposition.

To probe the effects of deposition temperature on the formation and structural order of self-assembled monolayers (SAMs) on Au(111) prepared by vapor deposition of 2-(2-methoxyethoxy)ethanethiol (CH3O(CH2)2O(CH2)2SH, EG2) for 24 h, we examined the surface structure and electrochemical behavior of the resulting EG2 SAMs using scanning tunneling microscopy (STM) and cyclic voltammetry (CV). STM observations clearly revealed that EG2 SAMs vapor-deposited on Au(111) at 298 K were composed of a disordered phase on the entire Au surface, whereas those formed at 323 K showed improved structural order, showing a mixed phase of ordered and disordered phases. Moreover, at 348 K, uniform and highly ordered EG2 SAMs on Au(111) were formed with a (2 × 3√3) packing structure. CV measurements showed sharp reductive desorption (RD) peaks at −0.818, −0.861, and −0.880 V for EG2 SAM-modified Au electrodes formed at 298, 323, and 348 K, respectively. More negative potential shifts of RD peaks with increasing deposition temperature are attributed to an increase in van der Waals interactions between EG2 molecular backbones resulting from the improved structural quality of EG2 SAMs. Our results obtained herein provide new insights into the formation and thermally driven structural order of oligo(ethylene glycol)-terminated SAMs vapor-deposited on Au(111).

Robust Transparent Titanium Dioxide Coating Based on the AACVD Process for Anticorrosion Marine Exploration.

Transparent and robust titanium dioxide (TiO2) coatings were prepared by the facile aerosol-assisted chemical vapor deposition (AACVD) method. The effects of deposition temperature and precursor concentration on the crystal growth and optical properties of TiO2 coating were investigated. It is found that the obtained TiO2 coating has strong adhesion to the substrate, which can effectively avoid mechanical scratches and wear by sharp objects, adhesive tape and steel wool. Besides, in the marine corrosion protection test, both the open circuit potential and electrochemical impedance of TiO2 coating immersed in artificial seawater for different times are greater than those of the bare S420 steel substrate. Particularly, the high-frequency phase angle of the TiO2 coating increases, and the impedance value at low frequency of 0.10 Hz is about 2 orders of magnitude higher than that of the bare S420 substrate. In addition, the significant decrease of corrosion products on the surface further proves that the deposited TiO2 coating exhibits better corrosion inhibition and excellent anticorrosion properties, which is expected in application of the surface coating protection of the marine exploration lens.

Synthesis of carbon molecular sieves from agricultural residues: Status, challenges and prospects

Adsorption is the most promising technology used in the gas separation and purification process. The key success of this technology relies on the selection of an adsorbent. Activated carbon and zeolites are the most commonly used adsorbents in the separation of particular gas from gaseous mixtures. Activated carbon deriving from fossil and biomass-based resources has wide pore size distribution and thereby results in lower selectivity. Whereas, zeolites synthesized from natural minerals are expensive which increases the cost of the purification process. Taking this into concern, the quest for synthesizing low-cost and effective adsorbents has gained greater attention in recent years. Carbon Molecular Sieves (CMSs), are considered as an attractive alternative to replace the conventional adsorbents. Furthermore, CMSs exhibit higher selectivity and adsorption capacity, due to their narrow micropore size distribution (0.3–0.5 nm). CMSs are synthesized from any organic carbonaceous precursor with low inorganic content. Since most of the agricultural residues fall under this category, they can be used as a feedstock for CMSs production. The synthesis of CMSs involves three stages: carbonization, activation, and pore modification. In this review, physicochemical characteristics of various agricultural residues, the effects of carbonization process parameters, activation methods, and pore modification techniques adopted for producing CMSs are comprehensively discussed. The effect of deposition temperature, time, and flow rate of depositing agent on pore characteristics of CMSs is briefed. The prospects and challenges in CMSs production are also studied. The insights in this review provide guidelines for synthesizing CMSs from agro-residues.

Reactive sputtered Ni-SDC cermet alloy anode for low-temperature solid oxide fuel cell

The facile deposition process for multi-component films is crucial in the development of thin film low-temperature solid oxide fuel cells (LT-SOFCs). Here, we report on the development and optimization of reactive sputtered Ni-SDC(Ni-Sm:CeO2) films for LT-SOFC anodes. The effects of oxygen partial pressure (PO2/PAr of 0 %–50 % at the sputter pressure of 30 mTorr) and deposition temperature on the physical, chemical and electrochemical properties of Ni-SDC films are studied. While the Ni-SDC anodes deposited at high PO2/PAr (>20 %) exhibited higher initial performance, they suffered from crack formation and massive Ni agglomeration upon operation due to NiO-to-Ni reduction and severe volume change. We further show that increasing the deposition temperature to 500 ℃ was effective in suppressing such Ni agglomeration and preserving the performance during operation.

Effect of deposition temperature on the residual stress of sputtered zinc-tin-oxide coatings deposited on polyethylene terephthalate (PET) substrates

In this paper the generation of stress during the deposition of Zinc-Tin-Oxide coatings by magnetron sputtering on a PET substrate in a roll-to-roll web coater is investigated in detail. The stress components originating from a mismatch in the thermal (σthermal) and hygroscopic (σhygroscopic) expansion coefficient, deformation due to the applied web tension (σweb tension) and intrinsic stress (σintrinsic) are discussed and compared. The substrate temperature is varied between 25 °C and 75 °C. In this temperature range σthermal plays a minor role (<23 %). σhygroscopic is the only component resulting in tensile stress in the coating and accounts for approximately (30–70) % of the total residual stress. σintrinsic as well as σweb tension led to compressive stress in the coating in a similar order of magnitude of (36–106) %. In conclusion, the total residual stress can be reduced by reduction of the web tension. The results show that an accurate determination of the thermo-mechanic substrate behaviour is necessary before starting the residual stress analysis, as non-reversible thermal shrinkage of the substrate may lead to significant errors in the stress analysis when not properly taken into account.

Ultraviolet photoconductivity and photoluminescence properties of spray pyrolyzed ZnO nanostructure: Effect of deposition temperature

The current investigation focuses on the influence of substrate temperature on Zinc Oxide (ZnO) thin films synthesized on glass substrates using 0.1 M precursor solution by low-cost spray pyrolysis technique. The x-ray diffraction peaks matched the hexagonal wurtzite structure of ZnO with the highest intensity along the (1 0 1) plane. Estimated the crystallite size, dislocation density, micro-strain, and the number of crystallites in the deposits using X ray diffraction (XRD) data. The crystallinity of the films deposited at 450 °C was maximum. Fibrous surface morphology is altered by varying the deposition temperature. The enhancement of optical transmittance and energy bandgap of the deposits with deposition temperature. The reduction of Urbach energy with an increase in the substrate temperature confirmed the improvement of crystallinity. The photoluminescence study revealed peaks associated with electron-hole pair recombination, zinc, and oxygen-related defects. The samples deposited at 450 °C showed minimum defects. Commission Internationale de l'éclairage (CIE) chromaticity diagram showed white light emission for sample deposited at 450 °C with the color temperature equal to 5378 °C which is agreeing with the temperature of a normal white light source. Improvement of free carrier concentration and n-type conductivity due to the enhancement of crystallinity was observed. ZnO thin films deposited at 450 °C showed maximum photocurrent when illuminated with UV light and faster rise and fall of photo resistance due to the improvement in the crystallinity and carrier concentration. The maximum photosensitivity was observed for the samples synthesized at 450 °C. Hence the ZnO thin films deposited at 450 °C can be used as ultraviolet photodetector material.

Investigation of the Tetrakis(dimethylamino)hafnium and H2S ALD Process: Effects of Deposition Temperature and Annealing

HfS2 has recently emerged as a promising 2D semiconductor, but the lack of a reliable method to produce continuous films on a large scale has hindered its spreading. The atomic layer deposition of the material with the precursor tetrakis-dimethylamino-hafnium with H2S is a relatively novel solution to this problem. This paper shows that it is a facile approach to synthesizing homogeneous and smooth HfS2 layers in a controlled and reproducible manner. The deposition is examined at different temperatures and layer thicknesses, exploring the ALD window of the deposition and the chemical, morphological and electronic properties of the films. The method yielded films with wafer-sized uniformity and controlled properties and is, thus, a promising way to prepare this important transition metal dichalcogenide material.

Effect of Deposition Temperature on Morphological, Optical, and Photocatalytic Properties of ZnO Thin Films Synthesized by Ultrasonic Spray Pyrolysis Method

AbstractZnO thin films are synthesized by an ultrasonic spray pyrolysis method, with the deposition temperature in a range between 250–450 °C. The obtained thin films are analyzed by X‐ray diffraction (XRD), atomic force microscopy (AFM), and photoluminescence (PL). The samples are used in a photocatalytic experiment to compare the degradation efficiency by methylene blue decomposition under UV irradiation. XRD patterns confirm a polycristalline wurtzite structure with preferred orientation along the (002) plane. AFM images reveal an important change in the shape and size of the grains constituting the surface. The roughness values are in the range of 17–93 nm. Thickness values of thin films deposited at 250, 350, and 450 °C are ≈0.9, 2.3, and 1.4 µ, respectively. From PL characterization, the spectra are found to be sensitive to the deposition temperature, where emission peaks with different forms and intensities are observed. One peak at 389 nm is attributed to the recombination of free excitons, and other peaks between 403–522 nm correspond to violet, blue, and green emissions indicating the presence of Zn vacancies, Zn interstitials, and oxygen vacancies, respectively, in the ZnO structure. The photocatlytic results show that the best photocatalytic efficiency of 88% is achieved by ZnO thin film deposited at 450 °C.

Effects of alloying and deposition temperature on phase formation and superconducting properties of TiZrTaNb-based high entropy-alloy films

A variety of bulk high-entropy alloy superconductors have been recently discovered; however, for thin films, only the TaNbHfZrTi high-entropy alloy system has been investigated for its superconducting properties. Here, (TiZrNbTa)1−xWx and (TiZrNbTa)1−xVx superconducting films have been produced by DC magnetron sputtering at different growth temperatures. The phase formation and superconducting behavior of these films depend on the content of alloying x and deposition temperature. A single body-centered cubic (bcc) phase can be formed in the low x range with enough driving energy for crystallinity, but phase transition between amorphous or two bcc structures is observed when increasing x. The highest superconducting transition temperature Tc reaches 8.0 K for the TiZrNbTa film. The superconducting transition temperature Tc of these films deposited at the same temperature decreases monotonically as a function of x. Increasing deposition temperature to 400 °C can enhance Tc for these films while retaining nearly equivalent compositions. Our experimental observations suggest that Tc of superconducting high entropy alloys relate to the atomic radii difference and electronegativity difference of involved elements beyond the valence electron number.

Fabrication of electrochromic TiO2:Nb films by ultrasonic spray pyrolysis

In this work, Nb-doped TiO2 (NTO) films were fabricated on the ITO glass substrates by ultrasonic spray pyrolysis (USP) method. The effects of deposition temperature and film thickness on the microstructure and electrochromic property of NTO film were investigated. With the increase of deposition temperature, the crystallinity of NTO films is improved and the substitution rate from Ti4+ to Nb5+ is increased, leading to an enhancement of the film electrochromic properties. Additionally, the growth direction of NTO grains strongly depends on the film thickness. With increasing the film thickness, the grain growth changes from random to (004) plane orientation. Correspondingly, the surface morphology of NTO grains also have changed from “equiaxed structure” to “sheet structure”. The NTO films composed of sheet-structured grains are porous. The porous structure is good for Li+ ions insertion/extraction. In this case, the NTO films have a higher electrochromic property. When the film thickness is 300 nm, the NTO films with sheet-structured grains have the optimal properties, which exhibit the precise independent spectral control over material transmittance in the visible (vis) and near-infrared (NIR) regimes. The optical contrast (ΔT%) is 30.73% in vis region and 39.72% in NIR region. The coloring and bleaching time are 35s and 8s, respectively. Moreover, the electrochemical property is still stable after 1000 cycles.

Effect of substrate roughness and PVD deposition temperatures on hardness and wear performance of AlCrN-coated WC-Co

Elevated temperature experienced in the cutting zone is the main issue contributing to severe wear and responsible in reducing the lifespan of cutting tools'. This study aims to improve the performance of the cutting tool by applying AlCrN coating on the WC-Co substrate using physical vapor deposition (PVD). Prior to the coating process, the WC-Co surface was chemically roughened by Murakami's solution, followed by Caro's solution for 10s. The etched substrates were coated with AlCrN at various PVD deposition temperatures. The scanning electron microscopy (SEM) showed the coating thickness increased from 1.24 μm to 2.78 μm. X-ray diffraction (XRD) pattern confirmed that both AlN and CrN phases dominated the coating layer indicated the presence of AlCrN coating. These XRD peaks were broader, indicating a smaller grain size (11.5 nm) produced at higher deposition temperatures. Apart from that, a minute amount of the Cr2N phase is also detected. The average compressive residual stresses ranged from −5.409 GPa to −1.707 GPa attributed to increased coating thickness associated with Cr2N+N2 → CrN phase transformation. There are no cracking and coating delamination observed at this state. The mechanical properties of the coated structure were further evaluated via Vickers microhardness and linear reciprocating tests. The hardness obtained ranged from 600 to 1617 HV0.2. While the coefficient of friction (CoF) measured was 0.21 after 240 m of sliding distance. The calculated wear rate was 2.283×10−4 mm3/N·m which exhibited a significant reduction in wear when coated at 450 °C compared to 4.550×10−4 mm3/N·m at a lower temperature (250 °C). Therefore, it can be concluded that the effect of roughened substrate and various PVD deposition temperatures have significantly influenced the coating phase formation, which subsequently effects the hardness and wear performance of AlCrN-coated tungsten carbide.

Slot-die processed perovskite solar cells: effects of solvent and temperature on device performances

We studied the effects of perovskite precursor solvents and deposition temperatures on perovskite-layer formation for slot-die coating based solar cell fabrication. To select better solvent and temperature conditions, various representative polar solvents (dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone, N,N-dimethylformamide (DMF), γ-butyrolactone) and various deposition temperatures (70 °C–150 °C), well-known as key conditions in conventional spin-coating systems, were studied and compared. Comparative studies revealed the DMSO:DMF (5:5) solvents and the 130 °C can provide better solar-cell performances with cell-efficiency up to 15.40% in slot-die based planar perovskite devices, demonstrating an advanced step for better-efficiency slot-die-coating based perovskite solar cells.

The effect of deposition temperature on microstructure and mechanical properties of SiC coatings on graphite

The effect of deposition temperature on microstructure and mechanical properties of SiC coatings on graphite

Effects of Deposition Potential and Temperature on Co(II) Reduction and Electrocrystallization for Preparing Nanocrystalline Co Coatings in Ethylene Glycol Solution

Based on cyclic voltammetry (CV) and chronoamperometry (CA) experiments, the effects of deposition potential and temperature on Co(II) reduction and electrocrystallization in ethylene glycol (EG) are reported. CV observations show that Co(II) reduction reaction is irreversible, and both the equilibrium potential and nucleation overpotential, η nucleation, move to more positive values as the temperature is improved. The diffusion coefficient of Co(II) is 2.24 × 10−6 cm2 s−1 at 323 K and the activation energy for bulk diffusion (E bd) of Co(II) is 22.03 ± 0.8 kJ mol−1. CA observations show that the Co electrocrystallization mechanism is a 3D nucleation and growth of a new phase under diffusion control. Its mechanism is an instantaneous regime at 323 K at various applied potentials, however, the mechanism changes from a progressive nucleation to an instantaneous nucleation at −1.10 V as the temperature increases. The cobalt nuclei are spherical microstructure, and these innumerable spherical crystal particles can align compactly to form many wirelike crystals bundles. XRD observation confirms the characteristic peak of crystalline Co with a preferred orientation direction and the average size of Co grains is 19 nm. It is also found that the Co coating thickness is affect by the potential and temperature.

Effects of deposition temperature on Mo/SiC Schottky contacts

We report on the results of our investigation of the effect of deposition temperature on molybdenum (Mo) used as Schottky contacts to fabricate silicon carbide (SiC) Schottky barrier diodes. The contacts were deposited using magnetron sputtering on n-type 4H-SiC at temperatures ranging from 25 to 900 °C. The fabricated diodes were characterized by current–voltage, current–voltage–temperature, and capacitance–voltage measurements. The diodes showed average Schottky barrier heights that decreased from 1.54 to 1.00 eV with increasing deposition temperature of the contacts. The average values of the ideality factors similarly decreased from 1.21 to 1.06 with increasing deposition temperature. However, the diodes with contacts deposited at 400–900 °C nearly maintained a constant ideality factor value of 1.06. The x-ray diffraction analysis indicated that silicides were formed at the interface for contacts deposited at or above 400 °C. The improved properties of the diodes with contacts deposited at higher temperatures are correlated with the formation of the interfacial alloys possessing improved electrical properties. This work demonstrates that high temperature deposition is another method for optimizing the properties of Mo contacts for the fabrication of 4H-SiC Schottky diodes for electronic applications in high power and high temperature environments.

The effects of doping and temperature on properties of electrochemically deposited Er3+ doped ZnSe thin films

Zinc Selenide (ZnSe) is a binary chalcogenide with band gap (Eg) of about 2.70 eV. Doping is used to tune band gap in order to optimize electrical and optical properties of thin films. The aim of this work was to determine the effects of doping and deposition temperature on the properties of erbium doped zinc selenide (Er3+;ZnSe). Undoped ZnSe and Er3+;ZnSe (1–4%)] were deposited at room temperature and at deposition temperatures between 40 °C and 100 °C on fluorine doped tin oxide (FTO) glass by electrochemical technique. The effects of doping and deposition temperature on the crystal structure, morphology, optical and electrical properties of the deposited ZnSe were investigated. XRD results showed that both undoped and Er3+;ZnSe were crystalline in nature with strong orientation along (111) and (311) directions. Peak intensity of Er3+;ZnSe decreased from Er1% to Er3% as doping concentration increased and then increased as concentration increased to 4%. The peaks were indexed to the cubic structure of ZnSe thin film with Er2% showing the highest purity. The UV–vis result revealed that the samples deposited at higher deposition temperatures [Er4%(80 °C) and Er4%(100 °C)] showed lower transmittance. Undoped ZnSe had band gap of 2.75 eV which approximated the bulk value. The band gap was observed to decrease as deposition temperature increased. The films deposited at room temperature had wider band gap (2.9 eV–2.61 eV) than those deposited above room temperature (2.21 eV–1.69 eV). The SEM micrograph revealed that low doping concentration (Er1%) had no effect on morphology. Er2% had the highest resistivity of about 8.41 × 103 Ωcm and lowest conductivity of 1.19 × 10−4 Ωcm−1. Doping and deposition temperature thus affected most of the investigated properties. Er3+;ZnSe (Er1% - Er4%) and Er4% (40 °C) – Er4% (100 °C) find applications as solar cell buffer layers and absorbers respectively.

Spatial atmospheric pressure molecular layer deposition of alucone films using dimethylaluminum isopropoxide as the precursor.

Trimethylaluminum is the most used aluminum precursor in atomic and molecular layer deposition (ALD/MLD). It provides high growth-per-cycle (GPC), is highly reactive and is relatively low cost. However, in the deposition of hybrid alucone films, TMA tends to infiltrate into the films requiring very long purge steps and thereby limiting the deposition rate (nm s-1) of the process. From our previous studies, we know that dimethylaluminum isopropoxide (DMAI) could be a potential candidate to substitute TMA in alucone depositions as it does not seem to infiltrate into the films. In this study, we perform a more detailed investigation of MLD of alucone on an atmospheric pressure spatial MLD system using DMAI as the aluminum precursor. The effect of deposition temperature and reactant purge times on the overall GPC has been investigated and a decreasing GPC with increasing deposition temperature and increasing EG purge time has been observed. Furthermore, the DMAI alucone films have been compared for their chemical environment and degradation with the films prepared using TMA and EG, showing striking similarities between the two. The results demonstrate that DMAI can be used as an alternative precursor to TMA for MLD of alucone films and this work can be used as a guide for designing efficient MLD processes in the future.

Effects of Deposition Temperature on the Microstructure, Mechanical Properties, High Temperature Corrosion and Oxidation Properties of Alcrnbtizr High Entropy Alloy Coatings

Effects of Deposition Temperature on the Microstructure, Mechanical Properties, High Temperature Corrosion and Oxidation Properties of Alcrnbtizr High Entropy Alloy Coatings