Inorganic Thin Film Materials

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Coatings coatings	3.4	4.7	2011	13.8 Days	CHF 2600
Materials materials	3.4	5.2	2008	13.9 Days	CHF 2600
Membranes membranes	4.2	4.4	2011	13.6 Days	CHF 2700

18 pages, 10378 KiB

Open AccessFeature PaperArticle

Effect of Negative Bias of HiPIMS and AIP Hybrid Deposition on Microstructure, Mechanical and Anti-Corrosive Properties of Cr₂N/TiN Multilayer Coatings

by Rong Tu, Yang Yuan, Mai Yang, Rui Min, Jiao Jiao, Qizhong Li, Meijun Yang, Baifeng Ji and Song Zhang

Coatings 2022, 12(6), 845; https://doi.org/10.3390/coatings12060845 - 16 Jun 2022

Cited by 2 | Viewed by 1956

Abstract

Multi-layered nitride coatings have been widely applied to improve the mechanical and anti-corrosive of metals and/or alloys. Cr₂N/TiN multilayer coatings were prepared by the combination of high-power pulsed magnetron sputtering (HiPIMS) and arc ion plating (AIP). The Cr₂N layer [...] Read more.

Multi-layered nitride coatings have been widely applied to improve the mechanical and anti-corrosive of metals and/or alloys. Cr₂N/TiN multilayer coatings were prepared by the combination of high-power pulsed magnetron sputtering (HiPIMS) and arc ion plating (AIP). The Cr₂N layer was co-deposited by HiPIMS and AIP, while the TiN layer was deposited by a single HiPIMS. With increasing the negative bias voltage (V_s) on substrate up to −100 V, the number and size of the droplets decreased; the average grain size of the coatings decreased from 9.4 to 7.5 nm and the hardness increased from 21.5 to 25.1 GPa, and the level of the adhesion of the coatings has reached HF1. The coatings obtained at V_s = −100 V present the best corrosion resistance in NaCl aqueous solution based on the anodic polarization curves and EIS spectroscopy. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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18 pages, 42798 KiB

Open AccessArticle

Application of SiON Coatings in Sandstone Artifacts Conservation

by Huoliang Qin, Yaping Wen and Qiang Liu

Coatings 2022, 12(6), 748; https://doi.org/10.3390/coatings12060748 - 29 May 2022

Viewed by 1924

Abstract

For a long time, a large number of sandstone cultural relics have been exposed to the outdoors, and they are facing unprecedented threats. Curing perhydropolysilazane at varied pyrolysis times results in a series of SiON solids. Fourier transform infrared absorption spectroscopy (FTIR) results [...] Read more.

For a long time, a large number of sandstone cultural relics have been exposed to the outdoors, and they are facing unprecedented threats. Curing perhydropolysilazane at varied pyrolysis times results in a series of SiON solids. Fourier transform infrared absorption spectroscopy (FTIR) results show that the Si−H bond disappears at 2163 cm⁻¹, and that the Si−O peaks at 460 cm⁻¹, becoming stronger during the pyrolysis of Perhydropolysilazane (PHPS) to SiON solids. X-ray photoelectron spectroscopy (XPS) results indicate a decrease in the proportion of N atoms from 22.71% to 3.38% and an increase in the proportion of O atoms from 59.74% to 69.1%, indicating a gradual production of SiO₂ from perhydropolysilazane. To protect the sandstone, the SiON protective layer and the commonly used protective materials—acrylic resin and polydimethylsiloxane—are applied. When compared to sandstone treated with acrylic resin B72 and polydimethylsiloxane coatings, SiON-coated sandstone effectively reduces porosity and water absorption. Ageing tests have shown that the SiON-coated sandstone is effective in resisting crystalline damage from sodium sulfate. These thenardites can change shape during formation, allowing their widespread distribution in different locations in the sandstone. The surface thenardite of the SiON-treated samples was smaller than that of the polydimethylsiloxane and acrylic resin B72-treated samples, while the untreated samples were flaky with obvious dehydration characteristics. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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10 pages, 3054 KiB

Open AccessArticle

Investigation of Electronic and Optical Properties of Al/Ag and Al/N Co-Implanted ZnO Thin Films

by Zijun Ma, Yanping Wei, Jijun Ding, Peirong Chang, Jinxiu Guo and Zhen Peng

Coatings 2022, 12(6), 733; https://doi.org/10.3390/coatings12060733 - 26 May 2022

Cited by 1 | Viewed by 1431

Abstract

Either metal/metal or metal/non-metal co-doping is one of the most effective methods to modulate the visible emission of ZnO. In this paper, ZnO, aluminum-doped ZnO (Al-ZnO), aluminum and silver co-doped ZnO (Al/Ag-ZnO), and aluminum and nitrogen co-doped ZnO (Al/N-ZnO) are deposited. Combining the [...] Read more.

Either metal/metal or metal/non-metal co-doping is one of the most effective methods to modulate the visible emission of ZnO. In this paper, ZnO, aluminum-doped ZnO (Al-ZnO), aluminum and silver co-doped ZnO (Al/Ag-ZnO), and aluminum and nitrogen co-doped ZnO (Al/N-ZnO) are deposited. Combining the substitution of zinc ions using Al and/or Ag doping and the substitution of oxygen ions using N doping is expected to introduce more interstitial zinc and oxygen vacancy defects related to visible light emission in ZnO films. The results indicate that the PL spectrum of ZnO shows a violet emission peak at 406 nm and other weak visible emission peaks. After Al doping, we observe a strong blue emission at 421 nm, and its intensity is further enhanced and attains the maximum for Al/N-ZnO. However, for Al/Ag-ZnO, the blue emission shifts toward a longer wavelength, and the intensity of the blue emission conversely decreases. Then, the band structures, the density of states (DOS), the partial density of states (PDOS), and the optical constant of doped ZnO are calculated using density functional theory (DFT). Based on the experimental and theoretical results, the enhancement mechanism of visible light is discussed. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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10 pages, 3848 KiB

Open AccessArticle

Structural, Morphologic, and Ferroelectric Properties of PZT Films Deposited through Layer-by-Layer Reactive DC Magnetron Sputtering

by Benas Beklešovas, Aleksandras Iljinas, Vytautas Stankus, Jurgita Čyvienė, Mindaugas Andrulevičius, Maksim Ivanov and Jūras Banys

Coatings 2022, 12(6), 717; https://doi.org/10.3390/coatings12060717 - 24 May 2022

Cited by 2 | Viewed by 2246

Abstract

Lead zirconate titanate (PZT) is a widely used material with applications ranging from piezoelectric sensors to developing non-volatile memory devices. Pb(Zr_xTi_1−x)O₃ films were deposited by DC reactive magnetron sputtering at a temperature range of (500–600) °C. X-ray diffraction [...] Read more.

Lead zirconate titanate (PZT) is a widely used material with applications ranging from piezoelectric sensors to developing non-volatile memory devices. Pb(Zr_xTi_1−x)O₃ films were deposited by DC reactive magnetron sputtering at a temperature range of (500–600) °C. X-ray diffraction (XRD) indicated the perovskite phase formation in samples synthesized at 550 °C, which agrees with Raman data analysis. Scanning electron microscopy (SEM) measurements supplemented XRD data and showed the formation of dense PZT microstructures. Further X-ray photoelectron spectroscopy (XPS) analysis confirmed that the Zr/Ti ratio corresponds to the Pb(Zr_0.58Ti_0.42)O₃ content. Dielectric measurement of the same sample indicated dielectric permittivity to be around 150 at room temperature, possibly due to the defects in the structure. P-E measurements show ferroelectric behavior at a temperature range of (50–180) °C. It was found that the remnant polarization increased with temperature, and at the same time, coercive field values decreased. Such behavior can be attributed to energetically deep defects. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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10 pages, 2924 KiB

Open AccessArticle

Hydrodynamic Analysis of the Thickness Variation in a Solid Film Formed by a Spin Coating Process

by Heesung Park

Coatings 2022, 12(5), 698; https://doi.org/10.3390/coatings12050698 - 19 May 2022

Cited by 1 | Viewed by 1895

Abstract

The surface profile of the film formed by spin coating is experimentally investigated in this paper. The unavoidable wavy form at the surface was observed when the ultraviolet curable resin was used. In addition, the surface thickness variation was directly related to the [...] Read more.

The surface profile of the film formed by spin coating is experimentally investigated in this paper. The unavoidable wavy form at the surface was observed when the ultraviolet curable resin was used. In addition, the surface thickness variation was directly related to the viscosity, disk rotation speed, and disk size. Fluid dynamic theory with non-dimensional analysis was conducted to describe the surface profile after the spin coating process. It was found that the film had been thickened until the viscosity force and Coriolis force were balanced. The Coriolis force, however, also affected the flow instability during the spinning of the disk. The film thickness variation is successfully described by using the non-dimensional factors. In addition, the edge bump which is induced by hydraulic jump is expressed by the relation of power law of Ekman, Weber, and Reynolds numbers. In this paper, the thickness variation and edge bump position are expressed by using hydrodynamic theory. It is also reveals that the Coriolis force acts based on the magnitude of thickness variation, and the surface tension affects the edge bump position. The presented relationships will contribute further understanding of the spin coating process. The outcome of this paper supports the cost-effective productions of electronic microcircuits and solar cells. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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18 pages, 3984 KiB

Open AccessArticle

Surface Optimization of Commercial Porous Ti Substrates by EPD of Titanium Nitride

by Cecilia Mortalò, Maria Cannio, Valentina Zin, Enrico Miorin, Francesco Montagner, Luca Pasquali, Monica Montecchi, Dino Norberto Boccaccini, Monica Fabrizio and Silvia Maria Deambrosis

Membranes 2022, 12(5), 531; https://doi.org/10.3390/membranes12050531 - 19 May 2022

Cited by 1 | Viewed by 2156

Abstract

In this work, the infiltration of TiN powders by electrophoretic deposition (EPD) in aqueous media was considered as alternative method to reduce the size craters and the roughness of commercial porous Ti substrates. Ti substrates can be used as suitable supports for the [...] Read more.

In this work, the infiltration of TiN powders by electrophoretic deposition (EPD) in aqueous media was considered as alternative method to reduce the size craters and the roughness of commercial porous Ti substrates. Ti substrates can be used as suitable supports for the deposition of dense hydrogen separation TiNx-based membranes by physical vapor deposition (PVD) techniques. The influence of various EPD deposition parameters on surface morphology and roughness of TiN-infiltrated substrates were investigated in order to optimize their surface properties. The results suggest that a multi-step EPD procedure is an effective technique for reducing substrate surface defects of commercial porous Ti substrates which could then be successfully used as proper supports for the deposition of dense and defect-free TiNx layers, also aligning the thermal mismatch between the active layer and the porous substrate. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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20 pages, 5591 KiB

Open AccessArticle

Mechanical and Tribological Properties of Ta-N and Ta-Al-N Coatings Deposited by Reactive High Power Impulse Magnetron Sputtering

by Valentina Zin, Francesco Montagner, Silvia Maria Deambrosis, Cecilia Mortalò, Lucio Litti, Moreno Meneghetti and Enrico Miorin

Materials 2022, 15(9), 3354; https://doi.org/10.3390/ma15093354 - 07 May 2022

Cited by 9 | Viewed by 1910

Abstract

In this article, the depositions and functional characterizations of Ta-N and Ta-Al-N coatings for protection purposes, grown by reactive high-power impulse magnetron sputtering onto silicon substrates, are described. Nitride films were grown while changing the substrate polarization voltage (i.e., the applied bias voltage) [...] Read more.

In this article, the depositions and functional characterizations of Ta-N and Ta-Al-N coatings for protection purposes, grown by reactive high-power impulse magnetron sputtering onto silicon substrates, are described. Nitride films were grown while changing the substrate polarization voltage (i.e., the applied bias voltage) during the process. Moreover, the effects of adding Al to form a ternary system and the resulting variation of the coatings’ mechanical and tribological properties have been widely investigated by nanoindentation, scratch, and wear tests. Micro-Raman characterization has been applied to the wear tracks to explore the comprehensive tribo-environment and wear mechanism. Interestingly, Ta-Al-N films, despite significantly improved mechanical properties, show a premature failure with respect to Ta-N coatings. The wear mechanisms of Ta-N and Ta-Al-N systems were revealed to be very different. Indeed, Ta-Al-N films suffer higher oxidation phenomena during wear, with the formation of an oxidized surface tribofilm and a reduced wear resistance, while Ta-N coatings undergo plastic deformation at the wear surface, with a slightly adhesive effect. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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10 pages, 2424 KiB

Open AccessArticle

Thermal Concentration on Thermoelectric Thin Film for Efficient Solar Energy Harvesting

by Lei Liu, Junjie Hong, Yiming Zhang, Ruoxi Li, Yutian Liao and Jun Huang

Coatings 2022, 12(5), 630; https://doi.org/10.3390/coatings12050630 - 05 May 2022

Cited by 5 | Viewed by 2042

Abstract

Thermoelectric generators can directly harvest and convert ambient thermal energy into electricity, which makes it ideal for thermal energy conversion. However, the limited working temperature gradient developed by direct solar radiation severely restricts the performance and the application of solar thermoelectric generators. Here, [...] Read more.

Thermoelectric generators can directly harvest and convert ambient thermal energy into electricity, which makes it ideal for thermal energy conversion. However, the limited working temperature gradient developed by direct solar radiation severely restricts the performance and the application of solar thermoelectric generators. Here, we report a multilayer thin film integrating a solar selective absorbing coating and a thermoelectric layer, where an in-plane temperature gradient was established. The temperature gradient was relatively large since the absorbed solar energy could only flow through the restricted cross-section of the thin film, representing a high thermal concentration. The fabricated thin-film solar thermoelectric generators (100 mm × 15 mm) achieve an open-circuit voltage of about 300 mV, and an output power of 0.83 μW under AM 1.5G conditions. Our work opens up a promising new strategy to achieve the simple and cost-effective conversion of solar energy into electricity by thermal concentration. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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8 pages, 1745 KiB

Open AccessArticle

Effects of Internal Relaxation of Biaxial Strain on Structural and Electronic Properties of In_0.5Al_0.5N Thin Film

by Guanglei Zhang, Guoqiang Qin and Feipeng Zhang

Coatings 2022, 12(5), 598; https://doi.org/10.3390/coatings12050598 - 28 Apr 2022

Cited by 1 | Viewed by 1446

Abstract

Ternary wurtzite In_0.5Al_0.5N films and coatings are promising candidates for microelectronic or optoelectronic devices due to their excellent physical and chemical properties. However, as a universal and non-negligible phenomenon, in-plane strain and its effects on the structure and properties [...] Read more.

Ternary wurtzite In_0.5Al_0.5N films and coatings are promising candidates for microelectronic or optoelectronic devices due to their excellent physical and chemical properties. However, as a universal and non-negligible phenomenon, in-plane strain and its effects on the structure and properties of In_0.5Al_0.5N still need systematic research. In particular, the deformation mechanism of In_0.5Al_0.5N under biaxial strain is not clearly understood currently. To reveal the role of the internal relaxation effect in lattice deformation, the lattice variation, thermal stability, and the electronic properties of ternary wurtzite compound In_0.5Al_0.5N under different biaxial strains are systematically investigated, using first-principles calculations based on density functional theory. The results indicate that, compared with the classic elastic deformation mechanism with constrained atomic coordinates, atom relaxation results in a much smaller Poisson ratio. Moreover, the plastic relaxation In_0.5Al_0.5N phase, generated by free atom relaxation, exhibits higher thermal stability than the elastic relaxation phase, so it is the most likely phase in reality when biaxial strain is imposed. Meanwhile, the biaxial strain has a remarkable influence on the electronic structure of In_0.5Al_0.5N films, where a non-linear variety of energy band gaps can be seen between the valance band and conduction band. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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16 pages, 3922 KiB

Open AccessArticle

An In-Depth Analysis of CdTe Thin-Film Deposition on Ultra-Thin Glass Substrates via Close-Spaced Sublimation (CSS)

by Nowshad Amin, Mohammad Rezaul Karim and Zeid Abdullah ALOthman

Coatings 2022, 12(5), 589; https://doi.org/10.3390/coatings12050589 - 25 Apr 2022

Cited by 6 | Viewed by 2356

Abstract

This study evaluated the impact of the deposition pressure on the formation of cadmium telluride (CdTe) thin films on ultra-thin (100 µm) Schott glass substrate at high temperature (T > 450 °C) by Close-Spaced Sublimation (CSS) technique. CdTe thin films were grown under [...] Read more.

This study evaluated the impact of the deposition pressure on the formation of cadmium telluride (CdTe) thin films on ultra-thin (100 µm) Schott glass substrate at high temperature (T > 450 °C) by Close-Spaced Sublimation (CSS) technique. CdTe thin films were grown under the pressure range of 1 Torr to 200 Torr to explore the impact of deposition pressure on CdTe thin-film properties. The microstructural, compositional and optoelectrical characteristics were examined. X-ray Diffraction (XRD) analysis revealed the cubic phase crystallite CdTe films with (111) preferential orientation. Scanning Electron Microscopy (SEM) demonstrated that the CdTe morphology and grain size could be regulated via the deposition pressure, whereby maximum grain growth was detected at low pressure (1–5 Torr). The thickness of CdTe films was reduced from 6 µm to 1.5 µm with the rise in deposition pressure. Moreover, the optical direct energy gap was derived in the range of 1.65–1.69 eV for the pressure value of 200 Torr to 1 Torr. Carrier density and resistivity were found to be in the order of 10¹³ cm⁻³ and 10⁴ Ω cm, respectively. The experimental results suggest that the pressure range of 1–5 Torr may be ideal for CSS-grown CdTe films on flexible ultra-thin glass (UTG) substrates. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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10 pages, 2147 KiB

Open AccessArticle

Decomposition Characteristics of the TTIP (Tetraisopropyl Orthotitanate) Precursor for Atomic Layer Deposition

by Hayeong Kim, Jihyeok An, SeonJeong Maeng, Jae-Soo Shin, Eunmi Choi and Ju-Young Yun

Materials 2022, 15(9), 3021; https://doi.org/10.3390/ma15093021 - 21 Apr 2022

Cited by 5 | Viewed by 2227

Abstract

The decomposition of tetraisopropyl orthotitanate (TTIP), a representative precursor used in the atomic layer deposition (ALD) of titanium dioxide (TiO₂) film, and the resulting changes in the thin film properties of the TiO₂ film were investigated. TTIP was evaluated after [...] Read more.

The decomposition of tetraisopropyl orthotitanate (TTIP), a representative precursor used in the atomic layer deposition (ALD) of titanium dioxide (TiO₂) film, and the resulting changes in the thin film properties of the TiO₂ film were investigated. TTIP was evaluated after exposure to thermal stress in an enclosed container. The vapor pressure results provide reasonable evidence that impurities are generated by the decomposition of TTIP under thermal stress. These impurities led to changes in the thermal properties of TTIP and changes in the growth rate, morphology, and composition of the thin film; in particular, these impurities increased the unstable oxidation states of Ti²⁺ (TiO) content in the TiO₂ film. The changes in the properties of the TiO₂ film resulting from the changes in the physical properties of TTIP led to a change in the properties of the device. We proved that the thermal stability of the precursor is a factor that can determine the reliability of the ALD process and the resulting thin film. Additionally, systematic evaluation of the precursor can provide useful information that can improve the development of the precursor and the consistency of the process. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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12 pages, 3367 KiB

Open AccessArticle

Mechanical Properties of Tensile Cracking in Indium Tin Oxide Films on Polycarbonate Substrates

by Jiali Zhou, Xuan Zhang, Xiaofeng Zhang, Wenqiao Zhang, Jiuyong Li, Yuandong Chen, Hongyan Liu and Yue Yan

Coatings 2022, 12(4), 538; https://doi.org/10.3390/coatings12040538 - 17 Apr 2022

Cited by 11 | Viewed by 2490

Abstract

The electro-mechanical behaviors of transparent conductive oxide film on polymer substrate are of great concern because they would greatly affect the stability and lifespan of the corresponding devices. In this paper, indium tin oxide (ITO) films with different thicknesses were deposited on a [...] Read more.

The electro-mechanical behaviors of transparent conductive oxide film on polymer substrate are of great concern because they would greatly affect the stability and lifespan of the corresponding devices. In this paper, indium tin oxide (ITO) films with different thicknesses were deposited on a polycarbonate (PC) sheet; meanwhile, in situ electrical resistance, in situ scanning electron microscopy and profilometry were employed to record the electrical resistance, morphologies and residual stress in order to investigate the fracture behavior and electrical-mechanical properties of ITO films under uniaxial tension loading. The electrical resistance changes, crack initiation, crack propagation and crack density evolution of ITO films were systematically characterized by in situ tests. Three fracture stages of ITO films were summarized: Ⅰ crack initiation, Ⅱ crack propagation, Ⅲ crack saturation and delamination. The crack initiation and electrical failure in a thinner ITO film occurred at relatively higher applied tensile strain; namely, the ductility of the film decreased as the film thickness increased. Residual compressive stress was recorded in the ITO films deposited on PC at room temperature and increased as the film thickness increased. Intrinsic crack initiation strain (CIS*) showed an opposite thickness dependence to residual strain (ε_r); the increase in residual compressive strain was counteracted by the decrease of intrinsic cohesion, leading to an overall decrease in effective crack initiation strain (CIS) when the film thickness increased. In addition, integrated with a formulated mechanics model and the analysis of the three fracture stages under tension, the fracture toughness and interfacial shear strength were quantitatively determined. As the film thickness increased (in the range of 50~500 nm), the fracture toughness decreased and the films were more prone to crack, whereas the interfacial shear strength increased and the films were less likely to delaminate. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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13 pages, 11370 KiB

Open AccessArticle

Mechanical Behaviour of Hard Chromium Deposited from a Trivalent Chromium Bath

by Robin Guillon, Olivier Dalverny, Benoit Fori, Celine Gazeau and Joel Alexis

Coatings 2022, 12(3), 354; https://doi.org/10.3390/coatings12030354 - 07 Mar 2022

Cited by 7 | Viewed by 2921

Abstract

In view of new environmental directives, hexavalent chromium baths can no longer be used to electroplate thick hard chromium deposits. To meet these industrial and environmental challenges, deposits are developed from trivalent chromium electrolytes. Cr(III) coatings are usually studied from the point of [...] Read more.

In view of new environmental directives, hexavalent chromium baths can no longer be used to electroplate thick hard chromium deposits. To meet these industrial and environmental challenges, deposits are developed from trivalent chromium electrolytes. Cr(III) coatings are usually studied from the point of view of the use properties and hardness, but their intrinsic properties remain widely unknown. The novelty of this work consists in the mechanical characterisation of these coatings. Properties such as hardness, stiffness, yield strength, and toughness of trivalent chromium deposits are determined by combining instrumented hardness tests, in situ FEG–SEM observations, and finite element simulations. These are explained according to the microstructure of the deposits, which is determined by scanning electron microscopy and X-ray diffraction. Their composition was characterised by glow discharge spectrometry. The structure characterisation deposits showed a more severely fractured coating of trivalent chromium than in the case of hexavalent chromium. Non-post-treated trivalent chromium deposits have a higher hardness (13 ± 1.7 GPa) and yield strength (5 GPa) than hexavalent chromium deposits. However, their stiffness (191 ± 13 GPa) and toughness (1.37 ± 0.13 MPa√m) are lower. Its mechanical behaviour is elastofragile. These differences in mechanical properties can be explained by the amorphous structure of the deposits and their high carbon content. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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6 pages, 1652 KiB

Open AccessArticle

Impact of Iterative Deuterium Annealing in Long-Channel MOSFET Performance

by Dong-Hyun Wang, Ja-Yun Ku, Dae-Han Jung, Khwang-Sun Lee, Woo Cheol Shin, Byung-Do Yang and Jun-Young Park

Materials 2022, 15(5), 1960; https://doi.org/10.3390/ma15051960 - 07 Mar 2022

Cited by 9 | Viewed by 2305

Abstract

In contrast to conventional forming gas annealing (FGA), high-pressure deuterium annealing (HPD) shows a superior passivation of dangling bonds on the Si/SiO₂ interface. However, research detailing the process optimization for HPD has been modest. In this context, this paper demonstrates the iterative [...] Read more.

In contrast to conventional forming gas annealing (FGA), high-pressure deuterium annealing (HPD) shows a superior passivation of dangling bonds on the Si/SiO₂ interface. However, research detailing the process optimization for HPD has been modest. In this context, this paper demonstrates the iterative impact of HPD for the better fabrication of semiconductor devices. Long-channel gate-enclosed FETs are fabricated as a test vehicle. After each cycle of the annealing, device parameters are extracted and compared depending on the number of the HPD. Based on the results, an HPD condition that maximizes on-state current (I_ON) but minimizes off-state current (I_OFF) can be provided. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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9 pages, 4417 KiB

Open AccessArticle

YSZ/LSM Composite Cathode Deposited by Solution Precursor Plasma Spraying

by Xiaoming Wang, Boen Tang, Penghui Wen, Weiping Dong, Linlin Wang and Dongyun Wang

Coatings 2022, 12(3), 321; https://doi.org/10.3390/coatings12030321 - 28 Feb 2022

Cited by 5 | Viewed by 2506

Abstract

In this paper, solution precursor plasma spraying (SPPS) was employed to prepare a porous YSZ/LSM composite cathode for solid oxide fuel cell (SOFC). The surface morphology and microstructure of the composite cathode deposits were characterized using SEM. The effect of annealing treatment on [...] Read more.

In this paper, solution precursor plasma spraying (SPPS) was employed to prepare a porous YSZ/LSM composite cathode for solid oxide fuel cell (SOFC). The surface morphology and microstructure of the composite cathode deposits were characterized using SEM. The effect of annealing treatment on SPPS YSZ/LSM microstructure was examined. The results showed that the as-sprayed YSZ/LSM deposits presented a porous aggregate with a size range of 10–60 μm when the alcohol was used as the solvent and the spraying distance was 60 mm. The porous aggregate was found to be composed mainly of small particles ranging from 0.2–2 μm, the YSZ/LSM composite cathode showed a finely porous microstructure with grain sizes from micrometers to sub-micrometers. A further annealing treatment at 1050 °C for 2 h in air resulted in a continuous microstructure porous coating with a perovskite phase. The polarization test results demonstrated that the minimum polarizations were 1.26 and 0.083 Ω·cm² for the composite cathode at 800 and 1000 °C, respectively. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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21 pages, 6238 KiB

Open AccessArticle

Synthesis and Characterization of Nanocrystalline Boron-Nitride Thin Films by Ion Milling and Thermal Treatment for Tribological Coatings: An Approach to Quantifying the Growth Dynamic Process

by Carlos Alberto Monezi, Korneli Grigoriev Grigorov, Aleksandar Tsanev, Armstrong Godoy, Jr., Antonio Augusto Couto, Arnaldo Oliveira Lima, Georgi Avdeev, Roumen Iankov and Marcos Massi

Materials 2022, 15(5), 1761; https://doi.org/10.3390/ma15051761 - 25 Feb 2022

Viewed by 2402

Abstract

Hexagonal boron-nitride nanoparticle coating was deposited on AISI 1045 steel surface. The deposition process included a transformation of B-containing thin organic film into nanocrystalline BN using two methods: thermal annealing at 450–850 °C and reactive ion etching in Ar/N₂ plasma. The film [...] Read more.

Hexagonal boron-nitride nanoparticle coating was deposited on AISI 1045 steel surface. The deposition process included a transformation of B-containing thin organic film into nanocrystalline BN using two methods: thermal annealing at 450–850 °C and reactive ion etching in Ar/N₂ plasma. The film structure, phases, and film morphology of deposited nanoparticles of boron nitride on AISI 1045 steel were characterized by XPS, XRD, and EDS. Post-annealing at 450 °C does not lead to the formation of a BN phase in the layer. A non-stoichiometric BN phase with nitrogen deficiency appears at 650 °C. At 850 °C annealing, the formed BN phase is completely stoichiometric. The effects of deposited and incorporated BN on the friction and hardness properties of AISI 1045 steel were also studied. The post-annealing process improved the hardness from 5.35 to 11.4 GPa, showing a pronounced linear temperature dependence. An original approach was adopted to quantify the energy-dependent growth constants based on the indentation load-discharge curves measured on samples treated under different conditions. Those constants describe the rate of the reactions and the type of interdiffusion process characteristic for each material used. This approach can partially fulfill the role of the Rutherford backscattering spectrometry profile, which is an expensive and time-consuming process, mainly when light elements such as boron and nitrogen are used. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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9 pages, 2571 KiB

Open AccessArticle

Titanium Oxide Coatings Deposited on MnZn Ferrite by a Molten Salt Reaction

by Hongyang Wang, Erchuang Cui, Chengbin Wang, Long Yan, Wei Zhang and Guojun Yu

Coatings 2022, 12(3), 298; https://doi.org/10.3390/coatings12030298 - 23 Feb 2022

Cited by 1 | Viewed by 1521

Abstract

Using molten salt reactions, Ti oxide coatings were successfully deposited on MnZn ferrite in a NaCl–KCl–K₂TiF₆ melt. The film formed on the surface of MnZn ferrite had a thickness of up to 20 μm and was composed of Ti oxides. [...] Read more.

Using molten salt reactions, Ti oxide coatings were successfully deposited on MnZn ferrite in a NaCl–KCl–K₂TiF₆ melt. The film formed on the surface of MnZn ferrite had a thickness of up to 20 μm and was composed of Ti oxides. The electric conductivity of the coatings was contributed to by the component Ti₂O₃ and depended on the concentration of Ti₂O₃ in the film. When the Ti₂O₃ content in the film increased, the surface resistance dropped to the order of 10⁻¹ Ω/□. The conductive film had the potential to be welded to the metal electrode, thus confirming that the molten salt reaction method could be used as a pre-treatment to realize the metallization of MnZn ferrite. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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20 pages, 3450 KiB

Open AccessArticle

Tuning the Electrical Properties of Tungsten Oxide Thin Films Deposited by Reactive Magnetron Sputtering

by Kouamé Boko Joël-Igor N’Djoré, Moussa Grafouté, Younes Makoudi, Waël Hourani and Christophe Rousselot

Coatings 2022, 12(2), 274; https://doi.org/10.3390/coatings12020274 - 18 Feb 2022

Cited by 6 | Viewed by 2635

Abstract

Tungsten oxide films are deposited onto glass and silicon substrates using reactive magnetron sputtering. Several studies have revealed difficulties in studying the electrical properties of resistive WO_x films. The main objective of this work is to propose the capacitance meter as a [...] Read more.

Tungsten oxide films are deposited onto glass and silicon substrates using reactive magnetron sputtering. Several studies have revealed difficulties in studying the electrical properties of resistive WO_x films. The main objective of this work is to propose the capacitance meter as a method for studying the electrical properties of resistive WO_x films. In addition, we aim to establish the correlation between the deposition process and WO_x physico-chemical properties. The study of the W-Ar-O₂ system hysteresis permitted us to gather the films into four zones, which were delimited by different oxygen flow rate intervals. The identification of these zones was confirmed by the deposition rate, target voltage, chemical composition and electrical properties of the films. A gradual evolution of the capacitance-voltage curves of the metal-oxide-semiconductor structures, with the WO_x thin films as the oxide layer, was globally observed with increasing oxygen flow rate. Ion density (N_ss) and flat band voltage (V_fb) evolved inversely to oxygen flow rate. The relationship between the evolution of N_ss and V_fb and the increase in oxygen flow rate reflects the improvement in oxygen stoichiometry in the WO_x films. The WO_x-Si interface trap density distribution (D_it) was also studied using the Terman method. It was observed that the films closest to stoichiometry, i.e., WO₂ or WO₃, showed the lowest values of D_it and N_ss. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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13 pages, 2864 KiB

Open AccessArticle

Improving the Anti-Corrosion and Anti-Wear Performance of Anodic Coating on the Surface of AA 5052 via Hydro-Thermal Treatment

by Debo Liu, Baofeng Zhang and Wei Song

Materials 2022, 15(4), 1447; https://doi.org/10.3390/ma15041447 - 15 Feb 2022

Cited by 4 | Viewed by 1608

Abstract

Hydro-thermal technology had been used to improve the anti-corrosion and anti-wear performance of anodizing coating on the surface of aluminium alloys. The micromorphology of the coating has been studied by SEM and results proved the coating had a compact structure. The element in [...] Read more.

Hydro-thermal technology had been used to improve the anti-corrosion and anti-wear performance of anodizing coating on the surface of aluminium alloys. The micromorphology of the coating has been studied by SEM and results proved the coating had a compact structure. The element in the substrate had been characterized by EDS and results proved Fe had redissolved to the Al substrate. The crystalline structure of the coating had been studied by XRD and results proved the anodic coating could be transformed into η-, p- and γ-alumina. The electrochemical properties had been researched using an electrochemical workstation; results proved after the coating had been treated by hydro-thermal technology, its anti-corrosion properties could be improved. At the hydro-thermal temperature of 400 ℃, its open circuit voltage and impedance reached −0.46 V and 160 kΩ × cm², respectively. The hardness of the coating had to be measured with an HVS-100 micro-hardness tester, with results proving that, after the hydro-thermal treatment, the hardness of the coating increased to 150 HV. The friction coefficient of the coating had been studied using a ball-on-disk tester, and the results proved it decreased to 0.46. The MMW-2 scratch tester had been used to measure the adhesion between the coating and substrate; results proved the coating had better adhesion with the substrate. The thermal conductivity of the coating had been studied by a heat conduction coefficient measurement device; results proved that it reached 11.2 W/m × K at a hydro-thermal temperature of 400 ℃, far higher than that of organic coating. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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9 pages, 4508 KiB

Open AccessArticle

Study on the Hydrophobic Modification of MTES/NH₃ Vapor Surface Treatment for SiO₂ Broadband Anti-Reflection Coating

by Qianyang Fan, Hanxi Liu, Xinli Jia, Lianghong Yan and Bo Jiang

Materials 2022, 15(3), 912; https://doi.org/10.3390/ma15030912 - 25 Jan 2022

Cited by 2 | Viewed by 2390

Abstract

In this article, ammonia and methyltriethoxysilane (MTES) were chosen as vapor phase modifiers for the base-catalyzed SiO₂ film. The surface of the film became more dense because of the hydroxyl condensation under the catalyst of ammonia, while the introduction of methyl groups [...] Read more.

In this article, ammonia and methyltriethoxysilane (MTES) were chosen as vapor phase modifiers for the base-catalyzed SiO₂ film. The surface of the film became more dense because of the hydroxyl condensation under the catalyst of ammonia, while the introduction of methyl groups by MTES of vapor treatment hindered the condensation to avoid over-change in film thickness. The hydrophobic of film was improved while the surface roughness of the film increased after treatment. The treated double-layer broadband anti-reflection (AR) coating retains high optical properties with the transmittance of 99.61%, 98.85%, and 99.16% at 355 nm, 532 nm, and 1064 nm, respectively. After exposing to the high humidity condition for 30 days, the broadband AR coating after treatment shows good optical durability, and the transmittance at 355 nm only drops by 0.12%. This vapor surface treatment can find potential application in high-power laser systems and solar cells. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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13 pages, 6343 KiB

Open AccessArticle

Development of Actuators for Repairing Cracks by Coating W Wires with Reactive Multilayers

by Gabriel Santos Silva, Lukasz Maj, Jerzy Morgiel, Maria Teresa Vieira and Ana Sofia Ramos

Materials 2022, 15(3), 869; https://doi.org/10.3390/ma15030869 - 24 Jan 2022

Viewed by 2411

Abstract

The aim of this research work was to optimize the coating of tungsten wires with reactive multilayer thin films and promote an exothermic self-propagating reaction. The ultimate goal is to use this heat to liquify low melting temperature materials, and thus block crack [...] Read more.

The aim of this research work was to optimize the coating of tungsten wires with reactive multilayer thin films and promote an exothermic self-propagating reaction. The ultimate goal is to use this heat to liquify low melting temperature materials, and thus block crack propagation in metallic materials. Ni/Me (Me = Al, Ti) multilayers were deposited by a DC (direct current) magnetron sputtering onto tungsten wires with diameters of 0.05 and 0.20 mm. The depositions were carried out to obtain films with near equiatomic average chemical composition and a modulation period (bilayer thickness) between 20 and 50 nm. The cross-section of the films was analyzed using electron microscopy before and after electrical ignition. A new substrate holder was developed to improve the quality of the Al/Ni films, allowing a reduction in the defects previously observed. The Ni/Ti thin films showed no discernible defects, regardless of the substrate holder. However, after ignition, the Ni + Ti reaction occurred in a non-self-propagating mode. Passing an electric current through a wire (ϕ = 0.05 mm) coated with an Al/Ni thin film, promoted a flash of light that was associated with the start of a self-propagating reaction. The reaction product was a B2-AlNi intermetallic phase. W wires coated with reactive multilayers may contribute to crack filling, and have potential to be self-healing actuators. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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7 pages, 1328 KiB

Open AccessArticle

Synthesis and Hydrophilicity Analysis of bis(propane-1,2-diol) Terminated Polydimethylsiloxanes (PDMSs)

by Lan-Hee Yang, Kyeong Eun Park and Sungho Yoon

Materials 2022, 15(3), 753; https://doi.org/10.3390/ma15030753 - 19 Jan 2022

Cited by 3 | Viewed by 2365

Abstract

Among silicone oligomers, polydimethylsiloxane (PDMS) is widely used industrially and has the advantage of improving the properties of other compounds, such as flame-retardant polyurethane (PU). However, as there are barriers to the synthesis of PU-grafted siloxane, owing to the polarity difference between isocyanate [...] Read more.

Among silicone oligomers, polydimethylsiloxane (PDMS) is widely used industrially and has the advantage of improving the properties of other compounds, such as flame-retardant polyurethane (PU). However, as there are barriers to the synthesis of PU-grafted siloxane, owing to the polarity difference between isocyanate and PDMS, numerous research efforts are being aimed at improving the hydrophilicity of PDMS. To improve the hydrophilicity and reactivity of hydroxyl PDMS, bis(propane-1,2-diol)-terminated PDMS (G-PDMS-G) with four hydroxy (-OH) groups was synthesized through ring-opening addition to replace both ends of linear α,ω-hydroxyl PDMS (HO-PDMS-OH) with glycidol, resulting in hydrophilic PDMS rather than dihydroxy PDMS. In all cases of G-PDMS-G, the contact angle and viscosity both decreased by more than 20%, confirming the improved hydrophilicity. In particular, G-PDMS-G-3, which has the largest molecular weight, demonstrated the greatest decrease in viscosity and contact angle (33%). Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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13 pages, 3777 KiB

Open AccessArticle

CNT-ZnO Core-Shell Photoanodes for Photoelectrochemical Water Splitting

by Vasu Prasad Prasadam, Ali Margot Huerta Flores, Jean-Nicolas Audinot and Naoufal Bahlawane

Coatings 2022, 12(1), 47; https://doi.org/10.3390/coatings12010047 - 01 Jan 2022

Cited by 9 | Viewed by 2694

Abstract

Solar-driven water splitting is a promising route toward clean H₂ energy and the photoelectrochemical approach attracts a strong interest. The oxygen evolution reaction is widely accepted as the performance limiting stage in this technology, which emphasizes the need of innovative anode materials. [...] Read more.

Solar-driven water splitting is a promising route toward clean H₂ energy and the photoelectrochemical approach attracts a strong interest. The oxygen evolution reaction is widely accepted as the performance limiting stage in this technology, which emphasizes the need of innovative anode materials. Metal oxide semiconductors are relevant in this respect owing to their cost-effectiveness and broad availability. The combination of chemical vapor deposition and atomic layer deposition was implemented in this study for the synthesis of randomly oriented CNT-ZnO core-shell nanostructures forming an adhering porous coating. Relative to a directly coated ZnO on Si, the porous structure enables a high interface area with the electrolyte and a resulting 458% increase of the photocurrent density under simulated solar light irradiation. The photoelectrochemical characterization correlates this performance to the effective electrons withdrawing along the carbon nanotubes (CNTs), and the resulting decrease of the onset potential. In terms of durability, the CNT-ZnO core–shell structure features an enhanced photo-corrosion stability for 8 h under illumination and with a voltage bias. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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12 pages, 7694 KiB

Open AccessArticle

Preparation of Double-Layer Crossed Silver Nanowire Film and Its Application to OLED

by Hengrui Xu, Ping Liu, Bing Huang, Xingwang Jiang, Qingguo Gao and Liming Liu

Coatings 2022, 12(1), 26; https://doi.org/10.3390/coatings12010026 - 27 Dec 2021

Cited by 4 | Viewed by 3061

Abstract

Ordered silver nanowire (AgNW) film can effectively reduce the density of nodes, reduce the roughness of the film, and increase its conductivity and transmittance. In this paper, a double-layer crossed AgNW grid film was prepared by the auxiliary stirring method. The average transmittance [...] Read more.

Ordered silver nanowire (AgNW) film can effectively reduce the density of nodes, reduce the roughness of the film, and increase its conductivity and transmittance. In this paper, a double-layer crossed AgNW grid film was prepared by the auxiliary stirring method. The average transmittance of the double-layer crossed AgNW grid film was found to be 80% in the 400–1000 nm band, with a square resistance of 35 Ω/sq. As a transparent conductive anode material, the ordered AgNW film was applied to fabricate a flexible green organic light-emitting diode (OLED). The experimental results showed that the threshold voltage of the OLED was only 5 V and the maximum luminance was 1500 cd/m². Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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14 pages, 6836 KiB

Open AccessArticle

Electroless Ni–P Plating on Mullite Powders and Study of the Mechanical Properties of Its Plasma-Sprayed Coating

by Kaiwang Chen, Penglin Zhang, Pengfei Sun, Xianming Niu and Chunlian Hu

Coatings 2022, 12(1), 18; https://doi.org/10.3390/coatings12010018 - 24 Dec 2021

Cited by 1 | Viewed by 2528

Abstract

To effectively improve the properties of a mullite coating and its interfacial bonding with the substrate, a Ni–P layer is deposited on the surface of mullite powders by electroless plating. The original mullite powders and coated mullite powders are then deposited onto stainless-steel [...] Read more.

To effectively improve the properties of a mullite coating and its interfacial bonding with the substrate, a Ni–P layer is deposited on the surface of mullite powders by electroless plating. The original mullite powders and coated mullite powders are then deposited onto stainless-steel substrates by plasma spraying. The growth mechanism of the Ni–P layer during the plating, the microstructures of the coated powders and mullite coating and the properties of the mullite coatings are characterized and analyzed. The results indicate that the Ni–P layer on the surface of the mullite powder has cell structures with a dense uniform distribution and grows in layers on the surface of the mullite powder. The crystallization behavior of Ni-P amorphous layer is induced by heat treatment. Compared to the original mullite coating, the coating prepared by the coated mullite powders has better manufacturability, stronger adhesion to the substrate, lower porosity (7.40%, 65% of that of the original coating), higher hardness (500.1 HV, 1.2 times that of the original coating), and better thermal cycle resistance (two times that of the original coating). The method of preparation of high-temperature thermal barrier coatings with coated mullite powders has a high application value. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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14 pages, 3746 KiB

Open AccessArticle

Effect of Charge Voltage on the Microstructural, Mechanical, and Tribological Properties of Mo–Cu–V–N Nanocomposite Coatings

by Haijuan Mei, Jicheng Ding, Junfeng Zhao, Ting Wang, Kaijian Huang, Zhaohui Guo, Quanshun Luo and Weiping Gong

Coatings 2021, 11(12), 1565; https://doi.org/10.3390/coatings11121565 - 20 Dec 2021

Cited by 5 | Viewed by 2732

Abstract

As an important high-power impulse magnetron sputtering (HIPIMS) parameter, charge voltage has a significant influence on the microstructure and properties of hard coatings. In this work, the Mo–Cu–V–N coatings were prepared at various charge voltages using HIPIMS technique to study their mechanical and [...] Read more.

As an important high-power impulse magnetron sputtering (HIPIMS) parameter, charge voltage has a significant influence on the microstructure and properties of hard coatings. In this work, the Mo–Cu–V–N coatings were prepared at various charge voltages using HIPIMS technique to study their mechanical and tribological properties. The microstructure was analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The mechanical and tribological properties were investigated by nano-indentation and ball-on-disc tribometer. The results revealed that all the coatings showed a solid-solution phase of B1-MoVN, the V atoms dissolved into face-centered cubic (FCC) B1-MoN lattice by partial substitution of Mo, and formed a solid-solution phase. Even at a high Cu content (~8.8 at. %), the Cu atoms existed as an amorphous phase. When the charge voltage increased, more energy was put into discharge, and the microstructure changed from coarse structure into dense columnar structure, resulting in the highest hardness of 28.2 GPa at 700 V. An excellent wear performance with low friction coefficient of 0.32 and wear rate of 6.3 × 10⁻¹⁷ m³/N·m was achieved at 750 V, and the wear mechanism was dominated by mild abrasive and tribo-oxidation wear. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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10 pages, 4273 KiB

Open AccessArticle

Anti-Reflection Coatings on 3D-Printed Components

by John Canning, Caspar Clark, Monica Dayao, Daniel de LaMela, Michael Logozzo and Jing Zhao

Coatings 2021, 11(12), 1519; https://doi.org/10.3390/coatings11121519 - 10 Dec 2021

Cited by 2 | Viewed by 2739

Abstract

The use of anti-reflection coatings on 3D-printed components to reduce both Fresnel reflections and scattering is explored. Two similar photo-initiated acrylic commercial material structures, known as Standard Clear (SC: T~60% @ λ = 800 nm) and VeroClear (VC: T~90% @ λ = 800 [...] Read more.

The use of anti-reflection coatings on 3D-printed components to reduce both Fresnel reflections and scattering is explored. Two similar photo-initiated acrylic commercial material structures, known as Standard Clear (SC: T~60% @ λ = 800 nm) and VeroClear (VC: T~90% @ λ = 800 nm), used specifically for optical components, are examined. The refractive indices for slab samples~(5 × 5 × 0.7) cm are measured at λ = 650 nm and averaged over the slab area: n(SC)~(1.49 ± 0.04) and n(VC)~(1.42 ± 0.03). Within experimental error, novel Shore D mapping is used to show hardness distribution across the surface flats, with VC slightly harder than SC, where VC = 85.9 ± 0.3 and SC = 84.4 ± 1.3, indicating uniform hardness. A TiO₂/MgF₂ anti-reflection twin-layer coating is deposited onto one side of an unpolished SC slab and binds well, passing standard peeling and humidity tests. Shore hardness increases to SC_COATED = 87.5 ± 1.5. It is found to reduce the measured Fresnel reflection and surface scatter by~65% without requiring major polishing, paving the way for lower-cost high-quality optics. The demonstration of successful anti-reflection coatings will benefit all 3D-printed component finishes, permitting viable film deposition more broadly. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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7 pages, 4821 KiB

Open AccessArticle

Fabrication of AlGaN High Frequency Bulk Acoustic Resonator by Reactive RF Magnetron Co-sputtering System

by Yu-Chen Chang, Ying-Chung Chen and Chien-Chuan Cheng

Materials 2021, 14(23), 7377; https://doi.org/10.3390/ma14237377 - 01 Dec 2021

Cited by 2 | Viewed by 2064

Abstract

In this study, aluminum gallium nitride (AlGaN) thin films are used as the piezoelectric layers to fabricate solidly mounted resonators (SMR) for high frequency acoustic wave devices. AlGaN film is deposited on a Bragg reflector, composed of three pairs of Mo and SiO [...] Read more.

In this study, aluminum gallium nitride (AlGaN) thin films are used as the piezoelectric layers to fabricate solidly mounted resonators (SMR) for high frequency acoustic wave devices. AlGaN film is deposited on a Bragg reflector, composed of three pairs of Mo and SiO₂ films, through a reactive radio frequency (RF) magnetron co-sputtering system at room temperature. The optimized deposition parameters of AlGaN film have a sputtering power of 175 W for Al target, sputtering power of 25 W for GaN target, N₂ flow ratio (N₂/Ar + N₂) of 60%, and sputtering pressure of 10 mTorr. The obtained AlGaN film has a smooth surface, uniform crystal grains, and strong c-axis orientation. The contents of Al and Ga in the AlGaN film, analyzed by energy dispersive X-ray spectroscopy (EDS) are 81% and 19%, respectively. Finally, the frequency response s₁₁ of the obtained SMR device shows that the center frequency is 3.60 GHz, the return loss is about −8.62 dB, the electromechanical coupling coefficient (k_t²) is 2.33%, the quality factor (Q) value is 96.93 and the figure of merit (FoM) value is 2.26. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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11 pages, 5849 KiB

Open AccessArticle

Electroplating Deposition of Bismuth Absorbers for X-ray Superconducting Transition Edge Sensors

by Jian Chen, Jinjin Li, Xiaolong Xu, Zhenyu Wang, Siming Guo, Zheng Jiang, Huifang Gao, Qing Zhong, Yuan Zhong, Jiusun Zeng and Xueshen Wang

Materials 2021, 14(23), 7169; https://doi.org/10.3390/ma14237169 - 25 Nov 2021

Cited by 1 | Viewed by 2043

Abstract

An absorber with a high absorbing efficiency is crucial for X-ray transition edge sensors (TESs) to realize high quantum efficiency and the best energy resolution. Semimetal Bismuth (Bi) has shown greater superiority than gold (Au) as the absorber due to the low specific [...] Read more.

An absorber with a high absorbing efficiency is crucial for X-ray transition edge sensors (TESs) to realize high quantum efficiency and the best energy resolution. Semimetal Bismuth (Bi) has shown greater superiority than gold (Au) as the absorber due to the low specific heat capacity, which is two orders of magnitude smaller. The electroplating process of Bi films is investigated. The Bi grains show a polycrystalline rhombohedral structure, and the X-ray diffraction (XRD) patterns show a typical crystal orientation of (012). The average grain size becomes larger as the electroplating current density and the thickness increase, and the orientation of Bi grains changes as the temperature increases. The residual resistance ratio (RRR) (R_{300 K}/R_{4.2 K}) is 1.37 for the Bi film (862 nm) deposited with 9 mA/cm² at 40 °C for 2 min. The absorptivity of the 5 μm thick Bi films is 40.3% and 30.7% for 10 keV and 15.6 keV X-ray radiation respectively, which shows that Bi films are a good candidate as the absorber of X-ray TESs. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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14 pages, 2660 KiB

Open AccessArticle

Stabilization of the Surface of ZnO Films and Elimination of the Aging Effect

by Khabibulla A. Abdullin, Maratbek T. Gabdullin, Sultan K. Zhumagulov, Guzal A. Ismailova, Lesya V. Gritsenko, Yevgeniya Y. Kedruk and Mojtaba Mirzaeian

Materials 2021, 14(21), 6535; https://doi.org/10.3390/ma14216535 - 30 Oct 2021

Cited by 11 | Viewed by 2204

Abstract

Zinc oxide is a promising multifunctional material. The practical use of nano- and polycrystalline ZnO devices faces a serious problem of instability of electrical and luminescent characteristics, due to the adsorption of oxygen by the surface during aging. In this paper, the aging [...] Read more.

Zinc oxide is a promising multifunctional material. The practical use of nano- and polycrystalline ZnO devices faces a serious problem of instability of electrical and luminescent characteristics, due to the adsorption of oxygen by the surface during aging. In this paper, the aging effect in ZnO films and nanorod arrays was studied. It was found that ZnO samples demonstrate different behavior of the degradation process, which corresponds to at least two different types of adsorbing surface sites for O₂, where O₂ adsorption is of a different nature. The first type of surface sites is rapidly depassivated after hydrogen passivation and the aging effect takes place due to these centers. The second type of surface sites has a stable structure after hydrogen passivation and corresponds to HO–ZnO sites. The XPS components of these sites include the Zn2p_3/2 peak at 1022.2 ± 0.2 eV and Zn2p_1/2 peak at 1045.2 ± 0.2 eV, with a part of the XPS O1s peak at 531.5 ± 0.3 eV. The annealing transforms the first type of site into the second one, and the subsequent short-term plasma treatment in hydrogen results in steady passivation, where the degradation of characteristics is practically reduced to zero. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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12 pages, 2716 KiB

Open AccessArticle

Residual Stress and Tribological Performance of ZrN Coatings Produced by Reactive Bipolar Pulsed Magnetron Sputtering

by Anna Maria Laera, Marcello Massaro, Domenico Dimaio, Aleksandar Vencl and Antonella Rizzo

Materials 2021, 14(21), 6462; https://doi.org/10.3390/ma14216462 - 28 Oct 2021

Cited by 4 | Viewed by 2114

Abstract

In the past few decades, ZrN thin films have been identified as wear resistant coatings for tribological applications. The mechanical and tribological properties of ZrN thin layers depend on internal stress induced by the adopted deposition techniques and deposition parameters such as pressure, [...] Read more.

In the past few decades, ZrN thin films have been identified as wear resistant coatings for tribological applications. The mechanical and tribological properties of ZrN thin layers depend on internal stress induced by the adopted deposition techniques and deposition parameters such as pressure, temperature, and growth rate. In sputtering deposition processes, the selected target voltage waveform and the plasma characteristics also play a crucial influence on physical properties of produced coatings. In present work, ZrN thin films, obtained setting different values of duty cycle in a reactive bipolar pulsed dual magnetron sputtering plant, were investigated to evaluate their residual stress through the substrate curvature method. A considerable progressive increase of residual stress values was measured at decreasing duty cycle, attesting the significant role of voltage waveform in stress development. An evident correlation was also highlighted between the values of the duty cycle and those of wear factor. The performed analysis attested an advantageous effect of internal stress, having the samples with high compressive stress, higher wear resistance. A downward trend for wear rate with the increase of internal residual stress was observed. The choice of suitable values of duty cycle allowed to produce ceramic coatings with improved tribological performance. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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11 pages, 2880 KiB

Open AccessArticle

Electrodeposition of Hybrid Magnetostrictive/Magnetoelectric Layered Systems

by Sara Abad, Alicia Prados, Marco Maicas, Neven Biskup, Maria Varela and Rocio Ranchal

Materials 2021, 14(21), 6304; https://doi.org/10.3390/ma14216304 - 22 Oct 2021

Viewed by 1697

Abstract

The potential use of electrodeposition to synthesize a hybrid magnetostrictive/magnetoelectric layered system is shown in this paper. By appropriately adjusting pH, growth potential, and electrolyte composition, it is possible to achieve thin films in which magnetoelectric oxide GaFeO₃ (GFO) is formed in [...] Read more.

The potential use of electrodeposition to synthesize a hybrid magnetostrictive/magnetoelectric layered system is shown in this paper. By appropriately adjusting pH, growth potential, and electrolyte composition, it is possible to achieve thin films in which magnetoelectric oxide GaFeO₃ (GFO) is formed in close contact with magnetostrictive metallic FeGa alloy. X-ray diffractometry shows the formation of FeGa as well as GFO and Fe oxides. Electron microscopy observations reveal that GFO mainly segregates in grain boundaries. Samples are ferromagnetic with an isotropic magnetic behavior in the sample plane. Magnetic stripes are observed by magnetic force microscopy and are correlated to Fe₃O₄. When its segregation is minimal, the absence of stripes can be used to monitor Fe oxide segregation. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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7 pages, 1340 KiB

Open AccessArticle

Microfabrication of VO₂ Thin Films via a Photosensitive Sol-Gel Method

by Chuanbao Wu, Yunwei Wang and Guangqiang Ma

Coatings 2021, 11(10), 1264; https://doi.org/10.3390/coatings11101264 - 18 Oct 2021

Cited by 6 | Viewed by 2366

Abstract

VO₂ films are widely used in photoelectric switches, smart glasses, storage media, and terahertz communications. In these applications, microfabrication technology is a very important process for producing microdevices or even improving film properties. In this paper, a novel photoetching microfabrication method is [...] Read more.

VO₂ films are widely used in photoelectric switches, smart glasses, storage media, and terahertz communications. In these applications, microfabrication technology is a very important process for producing microdevices or even improving film properties. In this paper, a novel photoetching microfabrication method is proposed for VO₂ thin films. First, a VO₂ precursor sol with ultraviolet photosensitivity was prepared using vanadyl acetylacetonate as the raw material and anhydrous methanol as the solvent. The dip-coated VO₂ gel film can be directly subjected to photolithography processing without coating additional photoresist by using the photosensitive sol. A fine pattern on the VO₂ film with good phase-transition performance can be obtained after annealing in a nitrogen atmosphere at 550 °C for 1 h. This method can be used to prepare grating, microarray, and various other fine patterns with the remarkable advantages of a low cost and simplified process, and the as-obtained material performances are unaffected using the method. It is a potential alternative method for optics, electronics, and magnetics devices based on VO₂ thin films. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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15 pages, 8764 KiB

Open AccessArticle

Research of a Novel Ag Temperature Sensor Based on Fabric Substrate Fabricated by Magnetron Sputtering

by Zong-Yao Yan, Jian-Yong Liu and Jia-Rong Niu

Materials 2021, 14(20), 6014; https://doi.org/10.3390/ma14206014 - 12 Oct 2021

Cited by 4 | Viewed by 2198

Abstract

TPU-coated polyester fabric was used as the substrate of a flexible temperature sensor and Ag nanoparticles were deposited on its surface as the temperature sensing layer by the magnetron sputtering method. The effects of sputtering powers and heat treatment on properties of the [...] Read more.

TPU-coated polyester fabric was used as the substrate of a flexible temperature sensor and Ag nanoparticles were deposited on its surface as the temperature sensing layer by the magnetron sputtering method. The effects of sputtering powers and heat treatment on properties of the sensing layers, such as the temperature coefficient of resistance (TCR), linearity, hysteresis, drift, reliability, and bending resistance, were mainly studied. The results showed that the TCR (0.00234 °C⁻¹) was the highest when sputtering power was 90 W and sputtering pressure was 0.8 Pa. The crystallinity of Ag particles would improve, as the TCR was improved to 0.00262 °C⁻¹ under heat treatment condition at 160°. The Ag layer obtained excellent linearity, lower hysteresis and drift value, as well as good reliability and bending resistance when the sputtering power was 90 W. The flexible temperature sensor based on the coated polyester fabric improved the softness and comfortableness of sensor, which can be further applied in intelligent wearable products. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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8 pages, 2327 KiB

Open AccessBrief Report

Sputter-Deposited Cr–Ag Films for Environmental Antimicrobial Applications

by Lijun Wang, Yingjie Wang, Powan Shum, Yuefeng Hou and Tao Fu

Coatings 2021, 11(10), 1153; https://doi.org/10.3390/coatings11101153 - 23 Sep 2021

Cited by 6 | Viewed by 2267

Abstract

Chromium–silver films with ≤ 39.2 at.% Ag were deposited by magnetron sputtering for antibacterial applications. X-ray diffraction and scanning electron microscopy analyses indicate that the films consist of Cr and Ag, and silver segregation is not obvious at the surface. The films are [...] Read more.

Chromium–silver films with ≤ 39.2 at.% Ag were deposited by magnetron sputtering for antibacterial applications. X-ray diffraction and scanning electron microscopy analyses indicate that the films consist of Cr and Ag, and silver segregation is not obvious at the surface. The films are hard (628–968 HV_0.001) and hydrophobic with low surface energy (12.8–26.8 mJ/m²). The drying time of water droplets is dependent on ambient conditions, material wettability and droplet size. The test against Escherichia coli indicates antibacterial ratios of 100% for the Cr–Ag films (action time 3 h). However, bacteria died within 15 min due to quick drying of the bacterial suspension in open ambient conditions. The Cr–Ag films would have potential antimicrobial applications in public environmental facilities. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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14 pages, 2185 KiB

Open AccessArticle

Self-Aligned Thin-Film Patterning by Area-Selective Etching of Polymers

by Chao Zhang, Markku Leskelä and Mikko Ritala

Coatings 2021, 11(9), 1124; https://doi.org/10.3390/coatings11091124 - 16 Sep 2021

Cited by 3 | Viewed by 4323

Abstract

Patterning of thin films with lithography techniques for making semiconductor devices has been facing increasing difficulties with feature sizes shrinking to the sub-10 nm range, and alternatives have been actively sought from area-selective thin film deposition processes. Here, an entirely new method is [...] Read more.

Patterning of thin films with lithography techniques for making semiconductor devices has been facing increasing difficulties with feature sizes shrinking to the sub-10 nm range, and alternatives have been actively sought from area-selective thin film deposition processes. Here, an entirely new method is introduced to self-aligned thin-film patterning: area-selective gas-phase etching of polymers. The etching reactions are selective to the materials underneath the polymers. Either O₂ or H₂ can be used as an etchant gas. After diffusing through the polymer film to the catalytic surfaces, the etchant gas molecules are dissociated into their respective atoms, which then readily react with the polymer, etching it away. On noncatalytic surfaces, the polymer film remains. For example, polyimide and poly(methyl methacrylate) (PMMA) were selectively oxidatively removed at 300 °C from Pt and Ru, while on SiO₂ they stayed. CeO₂ also showed a clear catalytic effect for the oxidative removal of PMMA. In H₂, the most active surfaces catalysing the hydrogenolysis of PMMA were Cu and Ti. The area-selective etching of polyimide from Pt was followed by area-selective atomic layer deposition of iridium using the patterned polymer as a growth-inhibiting layer on SiO₂, eventually resulting in dual side-by-side self-aligned formation of metal-on-metal and insulator (polymer)-on-insulator. This demonstrates that when innovatively combined with area-selective thin film deposition and, for example, lift-off patterning processes, self-aligned etching processes will open entirely new possibilities for the fabrication of the most advanced and challenging semiconductor devices. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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