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Materials, Volume 8, Issue 10 (October 2015)

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Open AccessArticle The Effects of Zr Doping on the Optical, Electrical and Microstructural Properties of Thin ZnO Films Deposited by Atomic Layer Deposition
Materials 2015, 8(10), 7230-7240; https://doi.org/10.3390/ma8105369
Received: 16 September 2015 / Revised: 14 October 2015 / Accepted: 15 October 2015 / Published: 27 October 2015
Cited by 10 | PDF Full-text (1605 KB) | HTML Full-text | XML Full-text
Abstract
Transparent conducting oxides (TCOs), with high optical transparency (≥85%) and low electrical resistivity (10−4 Ω·cm) are used in a wide variety of commercial devices. There is growing interest in replacing conventional TCOs such as indium tin oxide with lower cost, earth abundant
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Transparent conducting oxides (TCOs), with high optical transparency (≥85%) and low electrical resistivity (10−4 Ω·cm) are used in a wide variety of commercial devices. There is growing interest in replacing conventional TCOs such as indium tin oxide with lower cost, earth abundant materials. In the current study, we dope Zr into thin ZnO films grown by atomic layer deposition (ALD) to target properties of an efficient TCO. The effects of doping (0–10 at.% Zr) were investigated for ~100 nm thick films and the effect of thickness on the properties was investigated for 50–250 nm thick films. The addition of Zr4+ ions acting as electron donors showed reduced resistivity (1.44 × 10−3 Ω·cm), increased carrier density (3.81 × 1020 cm−3), and increased optical gap (3.5 eV) with 4.8 at.% doping. The increase of film thickness to 250 nm reduced the electron carrier/photon scattering leading to a further reduction of resistivity to 7.5 × 10−4 Ω·cm and an average optical transparency in the visible/near infrared (IR) range up to 91%. The improved n-type properties of ZnO: Zr films are promising for TCO applications after reaching the targets for high carrier density (>1020 cm−3), low resistivity in the order of 10−4 Ω·cm and high optical transparency (≥85%). Full article
(This article belongs to the Special Issue Atomic Layer Deposition of Functional Materials)
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Open AccessArticle Active Nanofibrous Membrane Effects on Gingival Cell Inflammatory Response
Materials 2015, 8(10), 7217-7229; https://doi.org/10.3390/ma8105376
Received: 25 August 2015 / Revised: 8 October 2015 / Accepted: 20 October 2015 / Published: 27 October 2015
Cited by 3 | PDF Full-text (10118 KB) | HTML Full-text | XML Full-text
Abstract
Alpha-melanocyte stimulating hormone (α-MSH) is involved in normal skin wound healing and also has anti-inflammatory properties. The association of α-MSH to polyelectrolyte layers with various supports has been shown to improve these anti-inflammatory properties. This study aimed to evaluate the effects of nanofibrous
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Alpha-melanocyte stimulating hormone (α-MSH) is involved in normal skin wound healing and also has anti-inflammatory properties. The association of α-MSH to polyelectrolyte layers with various supports has been shown to improve these anti-inflammatory properties. This study aimed to evaluate the effects of nanofibrous membrane functionalized with α-MSH linked to polyelectrolyte layers on gingival cell inflammatory response. Human oral epithelial cells (EC) and fibroblasts (FB) were cultured on plastic or electrospun Poly-#-caprolactone (PCL) membranes with α-MSH covalently coupled to Poly-L-glutamic acid (PGA-α-MSH), for 6 to 24 h. Cells were incubated with or without Porphyromonas gingivalis lipopolysaccharide (Pg-LPS). Cell proliferation and migration were determined using AlamarBlue test and scratch assay. Expression of interleukin-6 (IL-6), tumor necrosis factor (TNF-α), and transforming growth factor-beta (TGF-β) was evaluated using RT-qPCR method. Cell cultures on plastic showed that PGA-α-MSH reduced EC and FB migration and decreased IL-6 and TGF-β expression in Pg-LPS stimulated EC. PGA-α-MSH functionalized PCL membranes reduced proliferation of Pg-LPS stimulated EC and FB. A significant decrease of IL-6, TNF-α, and TGF-β expression was also observed in Pg-LPS stimulated EC and FB. This study showed that the functionalization of nanofibrous PCL membranes efficiently amplified the anti-inflammatory effect of PGA-α-MSH on gingival cells. Full article
(This article belongs to the Special Issue Therapeutics Delivery Systems for Regenerative Nanomedicine)
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Open AccessArticle Simplified Calculation Model and Experimental Study of Latticed Concrete-Gypsum Composite Panels
Materials 2015, 8(10), 7199-7216; https://doi.org/10.3390/ma8105375
Received: 21 August 2015 / Revised: 11 October 2015 / Accepted: 19 October 2015 / Published: 27 October 2015
Cited by 1 | PDF Full-text (8297 KB) | HTML Full-text | XML Full-text
Abstract
In order to address the performance complexity of the various constituent materials of (dense-column) latticed concrete-gypsum composite panels and the difficulty in the determination of the various elastic constants, this paper presented a detailed structural analysis of the (dense-column) latticed concrete-gypsum composite panel
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In order to address the performance complexity of the various constituent materials of (dense-column) latticed concrete-gypsum composite panels and the difficulty in the determination of the various elastic constants, this paper presented a detailed structural analysis of the (dense-column) latticed concrete-gypsum composite panel and proposed a feasible technical solution to simplified calculation. In conformity with mechanical rules, a typical panel element was selected and divided into two homogenous composite sub-elements and a secondary homogenous element, respectively for solution, thus establishing an equivalence of the composite panel to a simple homogenous panel and obtaining the effective formulas for calculating the various elastic constants. Finally, the calculation results and the experimental results were compared, which revealed that the calculation method was correct and reliable and could meet the calculation needs of practical engineering and provide a theoretical basis for simplified calculation for studies on composite panel elements and structures as well as a reference for calculations of other panels. Full article
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Open AccessArticle Effects of Electrodes on the Switching Behavior of Strontium Titanate Nickelate Resistive Random Access Memory
Materials 2015, 8(10), 7191-7198; https://doi.org/10.3390/ma8105374
Received: 30 August 2015 / Revised: 11 October 2015 / Accepted: 19 October 2015 / Published: 26 October 2015
Cited by 16 | PDF Full-text (3811 KB) | HTML Full-text | XML Full-text
Abstract
Strontium titanate nickelate (STN) thin films on indium tin oxide (ITO)/glass substrate were synthesized using the sol-gel method for resistive random access memory (RRAM) applications. Aluminum (Al), titanium (Ti), tungsten (W), gold (Au) and platinum (Pt) were used as top electrodes in the
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Strontium titanate nickelate (STN) thin films on indium tin oxide (ITO)/glass substrate were synthesized using the sol-gel method for resistive random access memory (RRAM) applications. Aluminum (Al), titanium (Ti), tungsten (W), gold (Au) and platinum (Pt) were used as top electrodes in the STN-based RRAM to probe the switching behavior. The bipolar resistive switching behavior of the set and reset voltages is in opposite bias in the Al/STN/ITO and Pt/STN/ITO RRAMs, which can be partly ascribed to the different work functions of top electrodes in the ITO. Analyses of the fitting results and temperature-dependent performances showed that the Al/STN/ITO switching was mainly attributed to the absorption/release of oxygen-based functional groups, whereas the Pt/STN/ITO switching can be associated with the diffusion of metal electrode ions. The Al/STN/ITO RRAM demonstrated a high resistance ratio of >106 between the high-resistance state (HRS) and the low-resistance state (LRS), as well as a retention ability of >105 s. Furthermore, the Pt/STN/ITO RRAM displayed a HRS/LRS resistance ratio of >103 and a retention ability of >105 s. Full article
(This article belongs to the Special Issue Selected Papers from ICASI 2015)
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Open AccessArticle Fabrication of Aluminum Tubes Filled with Aluminum Alloy Foam by Friction Welding
Materials 2015, 8(10), 7180-7190; https://doi.org/10.3390/ma8105373
Received: 10 September 2015 / Revised: 8 October 2015 / Accepted: 10 October 2015 / Published: 23 October 2015
Cited by 9 | PDF Full-text (7049 KB) | HTML Full-text | XML Full-text
Abstract
Aluminum foam is usually used as the core of composite materials by combining it with dense materials, such as in Al foam core sandwich panels and Al-foam-filled tubes, owing to its low tensile and bending strengths. In this study, all-Al foam-filled tubes consisting
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Aluminum foam is usually used as the core of composite materials by combining it with dense materials, such as in Al foam core sandwich panels and Al-foam-filled tubes, owing to its low tensile and bending strengths. In this study, all-Al foam-filled tubes consisting of ADC12 Al-Si-Cu die-cast aluminum alloy foam and a dense A1050 commercially pure Al tube with metal bonding were fabricated by friction welding. First, it was found that the ADC12 precursor was firmly bonded throughout the inner wall of the A1050 tube without a gap between the precursor and the tube by friction welding. No deformation of the tube or foaming of the precursor was observed during the friction welding. Next, it was shown that by heat treatment of an ADC12-precursor-bonded A1050 tube, gases generated by the decomposition of the blowing agent expand the softened ADC12 to produce the ADC12 foam interior of the dense A1050 tube. A holding time during the foaming process of approximately tH = 8.5 min with a holding temperature of 948 K was found to be suitable for obtaining a sound ADC12-foam-filled A1050 tube with sufficient foaming, almost uniform pore structures over the entire specimen, and no deformation or reduction in the thickness of the tube. Full article
(This article belongs to the Special Issue Metal Foams: Synthesis, Characterization and Applications)
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Open AccessCorrection Correction: Thermal Stability and Magnetic Properties of Polyvinylidene Fluoride/Magnetite Nanocomposites. Materials 2015, 8, 4553–4564
Materials 2015, 8(10), 7179; https://doi.org/10.3390/ma8105371
Received: 29 May 2015 / Accepted: 10 July 2015 / Published: 22 October 2015
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Abstract
In the published manuscript, “Thermal Stability and Magnetic Properties of Polyvinylidene Fluoride/Magnetite Nanocomposites. Materials 2015, 8(7), 4553–4564” [1], we detected that in three places the explanations were slightly incorrect. We apologize for any inconvenience this may have caused. [...] Full article
Open AccessArticle Improving Non-Destructive Concrete Strength Tests Using Support Vector Machines
Materials 2015, 8(10), 7169-7178; https://doi.org/10.3390/ma8105368
Received: 27 August 2015 / Revised: 16 September 2015 / Accepted: 13 October 2015 / Published: 22 October 2015
Cited by 5 | PDF Full-text (1812 KB) | HTML Full-text | XML Full-text
Abstract
Non-destructive testing (NDT) methods are important alternatives when destructive tests are not feasible to examine the in situ concrete properties without damaging the structure. The rebound hammer test and the ultrasonic pulse velocity test are two popular NDT methods to examine the properties
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Non-destructive testing (NDT) methods are important alternatives when destructive tests are not feasible to examine the in situ concrete properties without damaging the structure. The rebound hammer test and the ultrasonic pulse velocity test are two popular NDT methods to examine the properties of concrete. The rebound of the hammer depends on the hardness of the test specimen and ultrasonic pulse travelling speed is related to density, uniformity, and homogeneity of the specimen. Both of these two methods have been adopted to estimate the concrete compressive strength. Statistical analysis has been implemented to establish the relationship between hammer rebound values/ultrasonic pulse velocities and concrete compressive strength. However, the estimated results can be unreliable. As a result, this research proposes an Artificial Intelligence model using support vector machines (SVMs) for the estimation. Data from 95 cylinder concrete samples are collected to develop and validate the model. The results show that combined NDT methods (also known as SonReb method) yield better estimations than single NDT methods. The results also show that the SVM model is more accurate than the statistical regression model. Full article
(This article belongs to the Special Issue Selected Papers from ICASI 2015)
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Open AccessArticle Deformation and Plateau Region of Functionally Graded Aluminum Foam by Amount Combinations of Added Blowing Agent
Materials 2015, 8(10), 7161-7168; https://doi.org/10.3390/ma8105366
Received: 2 August 2015 / Revised: 22 September 2015 / Accepted: 6 October 2015 / Published: 21 October 2015
Cited by 1 | PDF Full-text (2916 KB) | HTML Full-text | XML Full-text
Abstract
Recently, to further improve the performance of aluminum foam, functionally graded (FG) aluminum foams, whose pore structure varies with their position, have been developed. In this study, three types of FG aluminum foam of aluminum alloy die casting ADC12 with combinations of two
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Recently, to further improve the performance of aluminum foam, functionally graded (FG) aluminum foams, whose pore structure varies with their position, have been developed. In this study, three types of FG aluminum foam of aluminum alloy die casting ADC12 with combinations of two different amounts of added blowing agent titanium(II) hydride (TiH2) powder were fabricated by a friction stir welding (FSW) route precursor foaming method. The combinations of 1.0–0 mass %, 0.4–0 mass %, and 0.2–0 mass % TiH2 were selected as the amounts of TiH2 relative to the mass of the volume stirred by FSW. The static compression tests of the fabricated FG aluminum foams were carried out. The deformation and fracture of FG aluminum foams fundamentally started in the high-porosity (with TiH2 addition) layer and shifted to the low-porosity (without TiH2 addition) layer. The first and second plateau regions in the relationship between compressive stress and strain independently appeared with the occurrence of deformations and fractures in the high- and low-porosity layers. It was shown that FG aluminum foams, whose plateau region varies in steps by the combination of amounts of added TiH2 (i.e., the combination of pore structures), can be fabricated. Full article
(This article belongs to the Special Issue Metal Foams: Synthesis, Characterization and Applications)
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Open AccessArticle Fatigue Life Prediction Based on Crack Closure and Equivalent Initial Flaw Size
Materials 2015, 8(10), 7145-7160; https://doi.org/10.3390/ma8105367
Received: 21 August 2015 / Revised: 2 October 2015 / Accepted: 13 October 2015 / Published: 21 October 2015
Cited by 4 | PDF Full-text (3273 KB) | HTML Full-text | XML Full-text
Abstract
Failure analysis and fatigue life prediction are necessary and critical for engineering structural materials. In this paper, a general methodology is proposed to predict fatigue life of smooth and circular-hole specimens, in which the crack closure model and equivalent initial flaw size (EIFS)
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Failure analysis and fatigue life prediction are necessary and critical for engineering structural materials. In this paper, a general methodology is proposed to predict fatigue life of smooth and circular-hole specimens, in which the crack closure model and equivalent initial flaw size (EIFS) concept are employed. Different effects of crack closure on small crack growth region and long crack growth region are considered in the proposed method. The EIFS is determined by the fatigue limit and fatigue threshold stress intensity factor Kth. Fatigue limit is directly obtained from experimental data, and Kth is calculated by using a back-extrapolation method. Experimental data for smooth and circular-hole specimens in three different alloys (Al2024-T3, Al7075-T6 and Ti-6Al-4V) under multiple stress ratios are used to validate the method. In the validation section, Semi-circular surface crack and quarter-circular corner crack are assumed to be the initial crack shapes for the smooth and circular-hole specimens, respectively. A good agreement is observed between model predictions and experimental data. The detailed analysis and discussion are performed on the proposed model. Some conclusions and future work are given. Full article
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Open AccessArticle 3D Microstructure Effects in Ni-YSZ Anodes: Influence of TPB Lengths on the Electrochemical Performance
Materials 2015, 8(10), 7129-7144; https://doi.org/10.3390/ma8105370
Received: 17 September 2015 / Revised: 13 October 2015 / Accepted: 15 October 2015 / Published: 21 October 2015
Cited by 9 | PDF Full-text (5310 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
3D microstructure-performance relationships in Ni-YSZ anodes for electrolyte-supported cells are investigated in terms of the correlation between the triple phase boundary (TPB) length and polarization resistance (Rpol). Three different Ni-YSZ anodes of varying microstructure are subjected to eight reduction-oxidation (redox)
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3D microstructure-performance relationships in Ni-YSZ anodes for electrolyte-supported cells are investigated in terms of the correlation between the triple phase boundary (TPB) length and polarization resistance (Rpol). Three different Ni-YSZ anodes of varying microstructure are subjected to eight reduction-oxidation (redox) cycles at 950 °C. In general the TPB lengths correlate with anode performance. However, the quantitative results also show that there is no simplistic relationship between TPB and Rpol. The degradation mechanism strongly depends on the initial microstructure. Finer microstructures exhibit lower degradation rates of TPB and Rpol. In fine microstructures, TPB loss is found to be due to Ni coarsening, while in coarse microstructures reduction of active TPB results mainly from loss of YSZ percolation. The latter is attributed to weak bottlenecks associated with lower sintering activity of the coarse YSZ. The coarse anode suffers from complete loss of YSZ connectivity and associated drop of TPBactive by 93%. Surprisingly, this severe microstructure degradation did not lead to electrochemical failure. Mechanistic scenarios are discussed for different anode microstructures. These scenarios are based on a model for coupled charge transfer and transport, which allows using TPB and effective properties as input. The mechanistic scenarios describe the microstructure influence on current distributions, which explains the observed complex relationship between TPB lengths and anode performances. The observed loss of YSZ percolation in the coarse anode is not detrimental because the electrochemical activity is concentrated in a narrow active layer. The anode performance can be predicted reliably if the volume-averaged properties (TPBactive, effective ionic conductivity) are corrected for the so-called short-range effect, which is particularly important in cases with a narrow active layer. Full article
(This article belongs to the Special Issue Electrode Materials)
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Open AccessArticle Advanced Chemical Reduction of Reduced Graphene Oxide and Its Photocatalytic Activity in Degrading Reactive Black 5
Materials 2015, 8(10), 7118-7128; https://doi.org/10.3390/ma8105363
Received: 22 July 2015 / Revised: 18 August 2015 / Accepted: 21 August 2015 / Published: 19 October 2015
Cited by 20 | PDF Full-text (3006 KB) | HTML Full-text | XML Full-text
Abstract
Textile industries consume large volumes of water for dye processing, leading to undesirable toxic dyes in water bodies. Dyestuffs are harmful to human health and aquatic life, and such illnesses as cholera, dysentery, hepatitis A, and hinder the photosynthetic activity of aquatic plants.
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Textile industries consume large volumes of water for dye processing, leading to undesirable toxic dyes in water bodies. Dyestuffs are harmful to human health and aquatic life, and such illnesses as cholera, dysentery, hepatitis A, and hinder the photosynthetic activity of aquatic plants. To overcome this environmental problem, the advanced oxidation process is a promising technique to mineralize a wide range of dyes in water systems. In this work, reduced graphene oxide (rGO) was prepared via an advanced chemical reduction route, and its photocatalytic activity was tested by photodegrading Reactive Black 5 (RB5) dye in aqueous solution. rGO was synthesized by dispersing the graphite oxide into the water to form a graphene oxide (GO) solution followed by the addition of hydrazine. Graphite oxide was prepared using a modified Hummers’ method by using potassium permanganate and concentrated sulphuric acid. The resulted rGO nanoparticles were characterized using ultraviolet-visible spectrophotometry (UV-Vis), X-ray powder diffraction (XRD), Raman, and Scanning Electron Microscopy (SEM) to further investigate their chemical properties. A characteristic peak of rGO-48 h (275 cm−1) was observed in the UV spectrum. Further, the appearance of a broad peak (002), centred at 2θ = 24.1°, in XRD showing that graphene oxide was reduced to rGO. Based on our results, it was found that the resulted rGO-48 h nanoparticles achieved 49% photodecolorization of RB5 under UV irradiation at pH 3 in 60 min. This was attributed to the high and efficient electron transport behaviors of rGO between aromatic regions of rGO and RB5 molecules. Full article
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Open AccessArticle Effect of Extrusion on the Mechanical and Rheological Properties of a Reinforced Poly(Lactic Acid): Reprocessing and Recycling of Biobased Materials
Materials 2015, 8(10), 7106-7117; https://doi.org/10.3390/ma8105360
Received: 21 August 2015 / Revised: 2 October 2015 / Accepted: 12 October 2015 / Published: 19 October 2015
Cited by 6 | PDF Full-text (4114 KB) | HTML Full-text | XML Full-text
Abstract
The aim of this research paper is to study the behaviour of a common used biopolymer (Poly(Lactic Acid) (PLA)) after several reprocesses and how two different types of additives (a melt strength enhancer and a nanoadditive) affect its mechanical and rheological properties. Systematic
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The aim of this research paper is to study the behaviour of a common used biopolymer (Poly(Lactic Acid) (PLA)) after several reprocesses and how two different types of additives (a melt strength enhancer and a nanoadditive) affect its mechanical and rheological properties. Systematic extraction of extrudate samples from a twin-screw compounder was done in order to study the effect in the properties of the reprocessed material. Detailed rheological tests on a capillary rheometer as well as mechanical studies on a universal tensile machine after preparation of injected specimens were carried out. Results evidenced that PLA and reinforced PLA materials can be reprocessed and recycled without a remarkable loss in their mechanical properties. Several processing restrictions and specific phenomena were identified and are explained in the present manuscript. Full article
(This article belongs to the Special Issue Green Composites)
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Open AccessArticle Numerical Study of the Effects of Residual Stress on Fretting Fatigue Using XFEM
Materials 2015, 8(10), 7094-7105; https://doi.org/10.3390/ma8105365
Received: 10 August 2015 / Revised: 4 October 2015 / Accepted: 9 October 2015 / Published: 19 October 2015
Cited by 2 | PDF Full-text (1162 KB) | HTML Full-text | XML Full-text
Abstract
Residual compressive stress can improve fretting fatigue strength. In this paper, the effects of residual stress on fretting fatigue of Al 2024-T351 alloy specimens are studied using a numerical approach. The extended finite element method combined with the cyclic cohesive zone model is
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Residual compressive stress can improve fretting fatigue strength. In this paper, the effects of residual stress on fretting fatigue of Al 2024-T351 alloy specimens are studied using a numerical approach. The extended finite element method combined with the cyclic cohesive zone model is adopted to model fretting fatigue crack growth behavior. It is shown that residual stress changes the fretting fatigue crack growth path and enhances fretting fatigue life. Crack initiation angle, depth of knee point, crack initiation life, crack propagation life and total life are greater for specimens with residual stress compared to specimens without residual stress. The effects of residual stress are more remarkable for specimens with a high intensity of residual stress. However, the effects of residual stress reduce at a high bulk load level. Full article
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Open AccessArticle Single-Crystal Y2O3 Epitaxially on GaAs(001) and (111) Using Atomic Layer Deposition
Materials 2015, 8(10), 7084-7093; https://doi.org/10.3390/ma8105364
Received: 9 August 2015 / Revised: 25 September 2015 / Accepted: 12 October 2015 / Published: 19 October 2015
Cited by 9 | PDF Full-text (1926 KB) | HTML Full-text | XML Full-text
Abstract
Single-crystal atomic-layer-deposited (ALD) Y\(_{\mathrm{2}}\)O\(_{\mathrm{3}}\) films 2 nm thick were epitaxially grown on molecular beam epitaxy (MBE) GaAs(001)-4 \(\times\) 6 and GaAs(111)A-2 \(\times\) 2 reconstructed surfaces. The in-plane epitaxy between the ALD-oxide films and GaAs was observed using \textit{in-situ} reflection high-energy electron diffraction in
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Single-crystal atomic-layer-deposited (ALD) Y\(_{\mathrm{2}}\)O\(_{\mathrm{3}}\) films 2 nm thick were epitaxially grown on molecular beam epitaxy (MBE) GaAs(001)-4 \(\times\) 6 and GaAs(111)A-2 \(\times\) 2 reconstructed surfaces. The in-plane epitaxy between the ALD-oxide films and GaAs was observed using \textit{in-situ} reflection high-energy electron diffraction in our uniquely designed MBE/ALD multi-chamber system. More detailed studies on the crystallography of the hetero-structures were carried out using high-resolution synchrotron radiation X-ray diffraction. When deposited on GaAs(001), the Y\(_{\mathrm{2}}\)O\(_{\mathrm{3}}\) films are of a cubic phase and have (110) as the film normal, with the orientation relationship being determined: Y\(_{\mathrm{2}}\)O\(_{\mathrm{3}}\)(\(110\))[\(001\)][\(\overline{1}10\)]//GaAs(\(001\))[\(110\)][\(1\overline{1}0\)]. On GaAs(\(111\))A, the Y\(_{\mathrm{2}}\)O\(_{\mathrm{3}}\) films are also of a cubic phase with (\(111\)) as the film normal, having the orientation relationship of Y\(_{\mathrm{2}}\)O\(_{\mathrm{3}}\)(\(111\))[\(2\overline{1}\overline{1}\)] [\(01\overline{1}\)]//GaAs (\(111\)) [\(\overline{2}11\)][\(0\overline{1}1\)]. The relevant orientation for the present/future integrated circuit platform is (\(001\)). The ALD-Y\(_{\mathrm{2}}\)O\(_{\mathrm{3}}\)/GaAs(\(001\))-4 \(\times\) 6 has shown excellent electrical properties. These include small frequency dispersion in the capacitance-voltage CV curves at accumulation of ~7% and ~14% for the respective p- and n-type samples with the measured frequencies of 1 MHz to 100 Hz. The interfacial trap density (Dit) is low of ~10\(^{12}\) cm\(^{−2}\)eV\(^{−1}\) as extracted from measured quasi-static CVs. The frequency dispersion at accumulation and the D\(_{it}\) are the lowest ever achieved among all the ALD-oxides on GaAs(\(001\)). Full article
(This article belongs to the Special Issue Epitaxial Materials 2015)
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Open AccessArticle A Micro Rectangular-Shaped Long-Period Fiber Grating Coated With Fe3O4 Nanoparticle Thin Overlay For Magnetic Sensing
Materials 2015, 8(10), 7074-7083; https://doi.org/10.3390/ma8105361
Received: 29 August 2015 / Revised: 3 October 2015 / Accepted: 8 October 2015 / Published: 19 October 2015
Cited by 1 | PDF Full-text (2525 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, we provide a novel micro rectangular-shaped long-period fiber grating (MRSLPFG) coated with Fe3O4 nanoparticles as the sensing material and packaged in polydimethylsiloxane (PDMS) for magnetic sensing application. The micro rectangular-shaped grating structures are fully dip coated with
[...] Read more.
In this paper, we provide a novel micro rectangular-shaped long-period fiber grating (MRSLPFG) coated with Fe3O4 nanoparticles as the sensing material and packaged in polydimethylsiloxane (PDMS) for magnetic sensing application. The micro rectangular-shaped grating structures are fully dip coated with the magnetic fluid and heated to form a thin solid film. This thin overlay is used as the sensing media to measure the external magnetic flux density parallel to the optical fiber axis. According to our experimental results, the phenomenon of the transmission loss of the MRSLPFG magnetic sensor was increased monotonically when the external applied magnetic flux density increased. As the external applied magnetic flux density was increased from 0 to 91.10 mT, the resonance attenuation dip of the MRSLPFG increased and the average sensitivity achieved during the experiments was 0.129 dB/mT. We infer that the aforementioned experimental results were due to the magnetostrictive effect exerted on the thin layer of Fe3O4 nanoparticles, which in turn induced slight longitudinal strains on the micro rectangular-shaped fiber grating structures under different magnetic flux density. Full article
(This article belongs to the Special Issue Selected Papers from ICASI 2015)
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