Journal of Nanomaterials The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Study of Reduced Graphene Oxide Preparation by Hummers’ Method and Related Characterization Mon, 06 Jul 2015 07:52:36 +0000 As a novel two-dimensional carbon material, graphene has fine potential applications in the fields of electron transfer agent and supercapacitor material for its excellent electronic and optical property. However, the challenge is to synthesize graphene in a bulk quantity. In this paper, graphite oxide was prepared from natural flake graphite by Hummers’ method through liquid oxidization, and the reduced graphene oxide was obtained by chemical reduction of graphene oxide using NH3H2O aqueous solution and hydrazine hydrate. The raw material graphite, graphite oxide, and reduced graphene oxide were characterized by X-ray diffraction (XRD), attenuated total reflectance-infrared spectroscopy (ATR-IR), and field emission scanning electron microscope (SEM). The results indicated that the distance spacing of graphite oxide was longer than that of graphite and the crystal structure of graphite was changed. The flake graphite was oxidized to graphite oxide and lots of oxygen-containing groups were found in the graphite oxide. In the morphologies of samples, fold structure was found on both the surface and the edge of reduced graphene oxide. Ning Cao and Yuan Zhang Copyright © 2015 Ning Cao and Yuan Zhang. All rights reserved. Microstructural Study on Oxygen Permeated Arc Beads Sun, 05 Jul 2015 12:06:40 +0000 We simulated short circuit of loaded copper wire at ambient atmosphere and successfully identified various phases of the arc bead. A cuprous oxide flake was formed on the surface of the arc bead in the rapid solidification process, and there were two microstructural constituents, namely, Cu-κ eutectic structure and solutal dendrites. Due to the arc bead formed at atmosphere during the local equilibrium solidification process, the phase of arc bead has segregated to the cuprous oxide flake, Cu-κ eutectic, and Cu phase solutal dendrites, which are the fingerprints of the arc bead permeated by oxygen. Kuan-Heng Liu, Yung-Hui Shih, Guo-Ju Chen, and Jaw-Min Chou Copyright © 2015 Kuan-Heng Liu et al. All rights reserved. A Study on the Conductivity Variation of Au Coated Conductive Particles in ACF Packaging Process Sun, 05 Jul 2015 11:41:47 +0000 In the ACF packaging process, a bonding force will be applied to the ACF structure. The finite element analysis is used to simulate the ACF packaging process. Material behavior is assumed to be superelastic for resin, viscoelastic for polymer matrix, and elastic-plastic for metal, such as bump, pad, chip, and Au-film. The axis-symmetric model is employed in FEA simulation with time-varying bonding force and operating temperature. In this study, the parameters, including conductive particle diameter, Au-film thickness, and bonding force, are analyzed with nonliner and temperature-dependent material properties. The simulation results indicate that bonding force and operating temperature have strong effects on the formation of concave on Au-film. In addition, surface wrinkle of Au-film will be induced by the bonding force. Both of the concaving and the wrinkling on Au-film will decrease the contact area between the conductive particle and the bump and the contact area between the conductive particle and the pad. Decrease of the contact area means increase of the total resistance for the ACF structure. The results show that the smaller the conductive particle diameter, the smaller the contact area. Generally, increasing the thickness of Au-film will decrease the contact areas, except at the Au-film thickness of 0.05 μm. Jao-Hwa Kuang, Chao-Ming Hsu, and Ah-Der Lin Copyright © 2015 Jao-Hwa Kuang et al. All rights reserved. Controlled Orientation and Improved Photovoltaic Characteristics of Cu(In,Ga)Se2 Solar Cells via Using In2Se3 Seeding Layers Sun, 05 Jul 2015 11:18:38 +0000 In2Se3 films were utilized as seeding layers in the synthesis of Cu(In,Ga)Se2 films via the spin-coating route. Selenizing the indium-containing precursors at 400°C resulted in the formation of the hexagonal γ-In2Se3 with the preferred (006) orientation. Increasing the selenization temperature to 500°C yielded the (300)-oriented γ-In2Se3. Using the preferred (006)-oriented In2Se3 as seeding layers produced the preferred (112)-oriented Cu(In,Ga)Se2 film because of the crystalline symmetry. In contrast, the use of the (300)-oriented In2Se3 as seeding layers yielded the (220/204)-oriented Cu(In,Ga)Se2 films. According to results obtained using SEM and the Hall effect, (112)-oriented Cu(In,Ga)Se2 films had a denser morphology and more favorable electrical properties. Using the (112)-oriented Cu(In,Ga)Se2 films as the absorber layer in the solar devices resulted in a significant increase in the conversion efficiency. Fu-Shan Chen, Che-Yuan Yang, Jen-Cheng Sung, and Chung-Hsin Lu Copyright © 2015 Fu-Shan Chen et al. All rights reserved. Elucidating How Surface Functionalization of Multiwalled Carbon Nanotube Affects Nanostructured MWCNT/Titania Hybrid Materials Sun, 05 Jul 2015 11:04:39 +0000 The new class of multiwalled carbon nanotube (MWCNT)/titania nanocomposites was prepared using a sol-gel technique. The addition of titania to MWCNTs has the potential to provide new capability for the development of electrical devices by taking advantage of the favorable electric characteristics of MWCNTs. MWCNTs were first functionalized with carboxyl, acyl chloride, amine, and hydroxyl groups and were then dispersed in a tetraisopropyl titanate (TIPT) solution via ultrasonic processing. After gelation, well-dispersed titania in the MWCNT/titania nanocomposites was obtained. Functionalized MWCNTs with varied functional groups were proved by Fourier transform infrared spectroscopy (FT-IR). For the nanocomposites, the degree of the sol-gel process were proved by Raman spectroscopy and wide-angle X-ray diffraction (WAXD). Furthermore, the morphology of the MWCNT/titania nanocomposites was observed using transmission electron microscopy (TEM). In the sol-gel process, the functionalized MWCNTs with carboxyl, acyl chloride, amine, and hydroxyl groups have resulted in the carbon nanotube-graft-titania nanocomposites with a network structure of titania between the carbon nanotubes. Cheng-Fu Yang, Wei-Chieh Hsu, Song-Mao Wu, and Chean-Cheng Su Copyright © 2015 Cheng-Fu Yang et al. All rights reserved. Sythesis, Modification, and Biosensing Characteristics of Au2S/AuAgS-Coated Gold Nanorods Sun, 05 Jul 2015 10:10:23 +0000 The Au2S/AuAgS-coated gold nanorods (Au2S/AuAgS/GNRs) are prepared by a facile synthesis method and functionally modified for their biosensing application. In the preparation process, the longitudinal plasmon resonance (LPR) bands of Au2S/AuAgS/GNRs can be changed by controlling the thickness of the chalcogenide layer coated on GNRs. Especially, the LPR band located at 800 nm is obtained for biosensing application in the near-infrared region. Furthermore, mercaptoundecanoic acid (MUA) and poly(styrenesulfonate) (PSS) are, respectively, used to modify Au2S/AuAgS/GNRs to acquire the functional nanoprobes; that is, MUA-modified and PSS-modified Au2S/AuAgS/GNRs and their different chemical reaction mechanisms are studied by the absorption spectrum and ξ-potential measurement. Then, the functional nanoprobes are incubated with anti-prostate-specific antigen (PSA) antibody to detect PSA. The experimental results demonstrate that the functional nanoprobes are sensitive to the target binding of PSA. Therefore, Au2S/AuAgS/GNRs are suitable to form the bioprobes for detection of PSA in early-phase prostate cancer. Yanting Liu, Yanan Ma, Jun Zhou, Xing Li, Shusen Xie, and Ruiqin Tan Copyright © 2015 Yanting Liu et al. All rights reserved. Novel Design for a Diffusive Solar Cell Window Sun, 05 Jul 2015 08:41:20 +0000 Building integrated photovoltaics (BIPV) are an important application of future solar energy development. The incorporation of solar cells into windows must not only maintain indoor natural lighting but also generate electrical power at the same time. In our continuing effort to improve the design of diffusion solar window, a more fundamental and efficient three-layer structure—glass/EVA with TiO2 nanoparticles embedded/glass—was proposed. In this work, a well-established ASAP ray-tracing model for a diffusive solar cell window was implemented to validate the outperformance of three-layer structure over primitive five-layer structure. Optical simulations were also implemented to perform its primary design for the determination of the optimal design parameters, such as the glass thickness, the EVA thickness, and the weight concentration of TiO2 nanoparticles. Based on the simulation results, an optimal design for a three-layer diffusive solar cell window prototype was proposed. And the influence of both EVA thickness and glass thickness on the power edge-exitance (solar cell power generation efficiency) of a DSCW was thoroughly investigated. Ruei-Tang Chen, Chih-Chieh Kang, Jeng-Feng Lin, Sheng-Wei Chiou, Hung-Hsiang Cheng, and Chih-Wen Lai Copyright © 2015 Ruei-Tang Chen et al. All rights reserved. Evaluation of Samarium Doped Hydroxyapatite, Ceramics for Medical Application: Antimicrobial Activity Sun, 05 Jul 2015 08:28:56 +0000 Samarium doped hydroxyapatite (Sm:HAp), (PO4)6(OH)2 (HAp), bionanoparticles with different have been successfully synthesized by coprecipitation method. Detailed characterization of samarium doped hydroxyapatite nanoparticles (Sm:HAp-NPs) was carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR). The biocompatibility of samarium doped hydroxyapatite was assessed by cell viability. The antibacterial activity of the Sm:HAp-NPs was tested against Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli) and Gram-positive bacteria (Enterococcus faecalis and Staphylococcus aureus). A linear increase of antimicrobial activity of P. aeruginosa has been observed when concentrations of Sm:HAp-NPs in the samples with were higher than 0.125 mg/mL. For Sm:HAp-NPs with a significant increase of antibacterial activity on E. coli was observed in the range 0.5–1 mg/mL. For low concentrations of Sm:HAp-NPs () from 0.031 to 0.125 mg/mL a high antibacterial activity on Enterococcus faecalis has been noticed. A growth of the inhibitory effect on S. aureus was observed for all concentrations of Sm:HAp-NPs with . C. S. Ciobanu, S. L. Iconaru, C. L. Popa, M. Motelica-Heino, and D. Predoi Copyright © 2015 C. S. Ciobanu et al. All rights reserved. TiO2-Based Nanomaterials: Design, Synthesis, and Applications Sun, 05 Jul 2015 08:01:57 +0000 Yuekun Lai, Luning Wang, Dawei Liu, Zhong Chen, and Changjian Lin Copyright © 2015 Yuekun Lai et al. All rights reserved. Numerical Investigation of Anode Thickness on the Performance and Heat/Mass Transport Phenomenon for an Anode-Supported SOFC Button Cell Sun, 05 Jul 2015 07:52:16 +0000 This study analyzes how anode thickness and working temperature affect heat/mass transport characteristics and cell performance of the anode-supported SOFC button cell by the finite-volume SIMPLE-C method coupled with preconditioned conjugate gradient methods. The numerical results of this work are compared with the experimental data and good agreement is observed. The simulation is carried out for various anode thicknesses (0.1, 0.5, and 1.0 mm) and working temperatures (873, 1073, and 1273 K). The results showed that the cell performance reduces about 5.05% as the anode thickness is increased from 0.1 mm to 1.0 mm; however, the influence of anode thickness on the heat/mass transport phenomenon is slight because the geometric size of anode thickness is tiny for the whole SOFC. In addition, the cell performance increases about 50.54% as the working temperature is increased from 873 K to 1273 K. A higher working temperature enhances the fluid velocity and convection and consequently promotes the chemical reaction and obtains a better cell performance. Shiang-Wuu Perng and Chang-Ren Chen Copyright © 2015 Shiang-Wuu Perng and Chang-Ren Chen. All rights reserved. Enhancing Algal Growth by Stimulation with LED Lighting and Ultrasound Sun, 05 Jul 2015 07:39:45 +0000 Algae are not only rich in natural nutrients, but are also a high-priced health food. An important constituent called “growth factor” is extracted from algae and used as an ingredient in medical drugs, foods, cosmetics, and other products. Its enormous potential market should not be taken lightly. Algae are mostly found near coastal areas and their habitats are limited by a number of natural factors, leading to large labor and financial expenditures to harvest. This report describes our study of indoor algae production using LED lights and ultrasound and manipulating other growth factors at different temperatures. Ultrasound treatment at the alga’s natural resonant frequency was varied to determine optimal algal growth using the Taguchi method to plan and to analyze the experiments. The results were very satisfying, showing an 8.23% increase in the growth rate by the fifth day due to ultrasound treatment and an amazing 27.01% growth rate due to biomechanical stimulation. Shao-Yi Hsia and Shiuh-Kuang Yang Copyright © 2015 Shao-Yi Hsia and Shiuh-Kuang Yang. All rights reserved. Advanced Functional Nanomaterials Synthesis and Nanocrystal Growth Technology Sun, 05 Jul 2015 06:35:38 +0000 Wei-Chun Chen, Hao-Chung Kuo, Rajanish Nath Tiwari, Shou-Yi Kuo, Fang-I Lai, and Ying-Lung Daniel Ho Copyright © 2015 Wei-Chun Chen et al. All rights reserved. Improvement of Lighting Uniformity and Phosphor Life in Field Emission Lamps Using Carbon Nanocoils Sun, 05 Jul 2015 06:29:04 +0000 The lighting performances and phosphor degradation in field emission lamps (FELs) with two different kinds of cathode materials—multiwalled carbon nanotubes (MWCNTs) and carbon nanocoils (CNCs)—were compared. The MWCNTs and CNCs were selectively synthesized on 304 stainless steel wire substrates dip-coated with nanosized Pd catalysts by controlling the growth temperature in thermal chemical vapor deposition, and the film uniformity can be optimized by adjusting the growth time. FELs were successfully fabricated by assembling these cathode filaments with a glass bulb-type anode. The FEL with the CNC cathode showed much higher lighting uniformity and light-spot density and a lower current at the same voltage than that with the MWCNT cathode filament, and its best luminous efficiency was as high as 75 lm/W at 8 kV. We also found that, for P22, the phosphor degradation can be effectively suppressed by replacing MWCNTs with CNCs in the cathode, due to the much larger total bright spot area and hence much lower current density loading on the anode. Kun-Ju Chung, Nen-Wen Pu, Meng-Jey Youh, Yih-Ming Liu, Ming-Der Ger, and Wen-Ko Huang Copyright © 2015 Kun-Ju Chung et al. All rights reserved. Effect of Substrate Temperature on the Thermoelectric Properties of the Sb2Te3 Thin Films Deposition by Using Thermal Evaporation Method Thu, 02 Jul 2015 12:21:57 +0000 The antimony-telluride (Sb2Te3) thermoelectric thin films were prepared on SiO2/Si substrates by thermal evaporation method. The substrate temperature that ranged from room temperature to 150°C was adopted to deposit the Sb2Te3 thin films. The effects of substrate temperature on the microstructures and thermoelectric properties of the Sb2Te3 thin films were investigated. The crystal structure and surface morphology of the Sb2Te3 thin films were characterized by X-ray diffraction analyses and field emission scanning electron microscope observation. The RT-deposited Sb2Te3 thin films showed the amorphous phase. Te and Sb2Te3 phases were coexisted in the Sb2Te3-based thin films as the substrate temperature was higher than room temperature. The average grain sizes of the Sb2Te3-based thin films were 39 nm, 45 nm, 62 nm, 84 nm, and 108 nm, as the substrate temperatures were 50°C, 75°C, 100°C, 125°C, and 150°C, respectively. The Seebeck coefficients, electrical conductivity, and power factor were measured at room temperature; we had found that they were critically dependent on the substrate temperature. Jyun-Min Lin, Ying-Chung Chen, Cheng-Fu Yang, and Wei Chen Copyright © 2015 Jyun-Min Lin et al. All rights reserved. Surface Patterning of PEDOT:PSS by Photolithography for Organic Electronic Devices Thu, 02 Jul 2015 11:35:22 +0000 Along with the development of organic electronics, conductive polymer of PEDOT:PSS has been attracting more and more attention because they possess various novel electrical, optical, and mechanical properties, which render them useful in modern organic optoelectronic devices. Due to its organic nature, it is lightweight and can be fabricated into flexible devices. For better device processing and integrating, it is essential to tune their surface morphologies, and photolithography is the best choice at present. In this paper, current PEDOT:PSS patterning approaches using photolithography are reviewed, and some of our works are also briefly introduced. Appropriate photolithographic patterning process for PEDOT:PSS will enable its application in future organic electronics. Shihong Ouyang, Yingtao Xie, Dongping Wang, Dalong Zhu, Xin Xu, Te Tan, and Hon Hang Fong Copyright © 2015 Shihong Ouyang et al. All rights reserved. Cu(In,Ga)Se2 Thin Films Codoped with Sodium and Bismuth Ions for the Use in the Solar Cells Thu, 02 Jul 2015 11:27:42 +0000 The codoping effects of sodium and bismuth ions on the characteristics of Cu(In,Ga)Se2 films prepared via the solution process were investigated in this study. When sodium and bismuth ions were incorporated into Cu(In,Ga)Se2, the ratio of the intensity of (112) diffraction peak to that of (220/204) diffraction peak was greatly increased. The codoping process not only enlarged the sizes of the grains in the films but also resulted in densification of the films. The carrier concentration of Cu(In,Ga)Se2 was found to be effectively increased to cause a reduction in the resistivity of the films. The above phenomena were attributed to the densified microstructures of the films and a decrease in the amount of the donor-type defects. The leakage current of the solar cells was found to be also decreased via the codoping process. Owing to the improved electrical properties of Cu(In,Ga)Se2 films, the conversion efficiency of the fabricated solar cells was significantly enhanced. Fu-Shan Chen, Jen-Cheng Sung, Che-Yuan Yang, and Chung-Hsin Lu Copyright © 2015 Fu-Shan Chen et al. All rights reserved. Thermal Properties of Asphalt Mixtures Modified with Conductive Fillers Thu, 02 Jul 2015 08:02:39 +0000 This paper investigates the thermal properties of asphalt mixtures modified with conductive fillers used for snow melting and solar harvesting pavements. Two different mixing processes were adopted to mold asphalt mixtures, dry- and wet-mixing, and two conductive fillers were used in this study, graphite and carbon black. The thermal conductivity was compared to investigate the effects of asphalt mixture preparing methods, the quantity, and the distribution of conductive filler on thermal properties. The combination of conductive filler with carbon fiber in asphalt mixture was evaluated. Also, rheological properties of modified asphalt binders with conductive fillers were measured using dynamic shear rheometer and bending beam rheometer at grade-specific temperatures. Based on rheological testing, the conductive fillers improve rutting resistance and decrease thermal cracking resistance. Thermal testing indicated that graphite and carbon black improve the thermal properties of asphalt mixes and the combined conductive fillers are more effective than the single filler. Byong Chol Bai, Dae-Wook Park, Hai Viet Vo, Samer Dessouky, and Ji Sun Im Copyright © 2015 Byong Chol Bai et al. All rights reserved. In Vivo Osteogenesis of Vancomycin Loaded Nanohydroxyapatite/Collagen/Calcium Sulfate Composite for Treating Infectious Bone Defect Induced by Chronic Osteomyelitis Thu, 02 Jul 2015 06:06:05 +0000 A novel antibacterial bone graft substitute was developed to repair bone defects and to inhibit related infections simultaneously. This bone composite was prepared by introducing vancomycin (VCM) to nanohydroxyapatite/collagen/calcium sulphate hemihydrate (nHAC/CSH). XRD, SEM, and CCK-8 tests were used to characterize the structure and morphology and to investigate the adhesion and proliferation of murine osteoblastic MC3T3-E1 cell on VCM/nHAC/CSH composite. The effectiveness in restoring infectious bone defects was evaluated in vivo using a rabbit model of chronic osteomyelitis. Our in vivo results implied that the VCM/nHAC/CSH composite performed well both in antibacterial ability and in bone regeneration. This novel bone graft substitute should be very promising for the treatment of bone defect-related infection in orthopedic surgeries. Xiaojie Lian, Kezheng Mao, Xi Liu, Xiumei Wang, and Fuzhai Cui Copyright © 2015 Xiaojie Lian et al. All rights reserved. Titanium Carbide Nanocrystals Synthesized from a Metatitanic Acid-Sucrose Precursor via a Carbothermal Reduction Wed, 01 Jul 2015 12:03:36 +0000 A TiC powder is synthesized from a micron-sized mesoporous metatitanic acid-sucrose precursor (precursor M) by a carbothermal reduction process. Control specimens are also prepared using a nanosized TiO2-sucrose precursor (precursor T) with a higher cost. When synthesized at 1500°C for 2 h in flowing Ar, the characteristics of the synthesized TiC from precursor M are similar to those of the counterpart from precursor T in terms of the crystal size (58.5 versus 57.4 nm), oxygen content (0.22 wt% versus 0.25 wt%), and representative sizes of mesopores: approximately 2.5 and 19.7–25.0 nm in both specimens. The most salient differences of the two specimens are found in the TiC from precursor M demonstrating (i) a higher crystallinity based on the distinctive doublet peaks in the high-two-theta XRD regime and (ii) a lower specific surface area (79.4 versus 94.8 m2/g) with a smaller specific pore volume (0.1 versus 0.2 cm3/g) than the counterpart from precursor T. Hyunho Shin and Jun-Ho Eun Copyright © 2015 Hyunho Shin and Jun-Ho Eun. All rights reserved. Synthesis of Three-Dimensional Fe3O4/Graphene Aerogels for the Removal of Arsenic Ions from Water Wed, 01 Jul 2015 09:36:22 +0000 We report the synthesis of three-dimensional Fe3O4/graphene aerogels (GAs) and their application for the removal of arsenic (As) ions from water. The morphology and properties of Fe3O4/GAs have been characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and superconducting quantum inference device. The 3D nanostructure shows that iron oxide nanoparticles are decorated on graphene with an interconnected network structure. It is found that Fe3O4/GAs own a capacity of As(V) ions adsorption up to 40.048 mg/g due to their remarkable 3D structure and existence of magnetic Fe3O4 nanoparticles for separation. The adsorption isotherm matches well with the Langmuir model and kinetic analysis suggests that the adsorption process is pseudo-second-ordered. In addition to the excellent adsorption capability, Fe3O4/GAs can be easily and effectively separated from water, indicating potential applications in water treatment. Yan Ye, Da Yin, Bin Wang, and Qingwen Zhang Copyright © 2015 Yan Ye et al. All rights reserved. Suspension Synthesis of Surfactant-Free Cuprous Oxide Quantum Dots Wed, 01 Jul 2015 08:01:32 +0000 Suspension methods were used to synthesize surfactant-free Cu2O quantum dots (Cu2O-QDs) in high precursor concentrations using sodium hypophosphite as a reducing agent. Transmission electron microscopy (TEM) observations indicated that a large amount of Cu2O-QDs were synthesized with diameters ranging from 7 to 10 nm. We propose a mechanism where DMSO acts as a surface passivation agent, explaining the possible formation of Cu2O-QDs. Noticeably, the Cu2O-QDs exhibited high and stable catalytic activity for the reduction of rhodamine B. Dongzhi Lai, Tao Liu, Xinyun Gu, Ying Chen, Jin Niu, Lingmin Yi, and Wenxing Chen Copyright © 2015 Dongzhi Lai et al. All rights reserved. Synthesis of Inorganic Nanocomposites by Selective Introduction of Metal Complexes into a Self-Assembled Block Copolymer Template Wed, 01 Jul 2015 07:18:51 +0000 Inorganic nanocomposites have characteristic structures that feature expanded interfaces, quantum effects, and resistance to crack propagation. These structures are promising for the improvement of many materials including thermoelectric materials, photocatalysts, and structural materials. Precise control of the inorganic nanocomposites’ morphology, size, and chemical composition is very important for these applications. Here, we present a novel fabrication method to control the structures of inorganic nanocomposites by means of a self-assembled block copolymer template. Different metal complexes were selectively introduced into specific polymer blocks of the block copolymer, and subsequent removal of the block copolymer template by oxygen plasma treatment produced hexagonally packed porous structures. In contrast, calcination removal of the block copolymer template yielded nanocomposites consisting of metallic spheres in a matrix of a metal oxide. These results demonstrate that different nanostructures can be created by selective use of processes to remove the block copolymer templates. The simple process of first mixing block copolymers and magnetic nanomaterial precursors and then subsequently removing the block copolymer template enables structural control of magnetic nanomaterials, which will facilitate their applicability in patterned media, including next-generation perpendicular magnetic recording media. Hiroaki Wakayama and Hirotaka Yonekura Copyright © 2015 Hiroaki Wakayama and Hirotaka Yonekura. All rights reserved. The Effect of Annealing on Nanothick Indium Tin Oxide Transparent Conductive Films for Touch Sensors Wed, 01 Jul 2015 07:13:30 +0000 This study aims to discuss the sheet resistance of ultrathin indium tin oxide (ITO) transparent conductive films during the postannealing treatment. The thickness of the ultrathin ITO films is 20 nm. They are prepared on B270 glass substrates at room temperature by a direct-current pulsed magnetron sputtering system. Ultrathin ITO films with high sheet resistance are commonly used for touch panel applications. As the annealing temperature is increased, the structure of the ultrathin ITO film changes from amorphous to polycrystalline. The crystalline of ultrathin ITO films becomes stronger with an increase of annealing temperature, which further leads to the effect of enhanced Hall mobility. A postannealing treatment in an atmosphere can enhance the optical transmittance owing to the filling of oxygen vacancies, but the sheet resistance rises sharply. However, a higher annealing temperature, above 250°C, results in a decrease in the sheet resistance of ultrathin ITO films, because more Sn ions become an effective dopant. An optimum sheet resistance of 336 Ω/sqr was obtained for ultrathin ITO films at 400°C with an average optical transmittance of 86.8% for touch sensor applications. Shih-Hao Chan, Meng-Chi Li, Hung-Sen Wei, Sheng-Hui Chen, and Chien-Cheng Kuo Copyright © 2015 Shih-Hao Chan et al. All rights reserved. The Reliability Improvement of Cu Interconnection by the Control of Crystallized - Diffusion Barrier Wed, 01 Jul 2015 06:46:04 +0000 Ta/TaN bilayers have been deposited by a commercial self-ionized plasma (SIP) system. The microstructures of Ta/TaN bilayers have been systematically characterized by X-ray diffraction patterns and cross-sectional transmission electron microscopy. TaN films deposited by SIP system are amorphous. The crystalline behavior of Ta film can be controlled by the N concentration of underlying TaN film. On amorphous TaN film with low N concentration, overdeposited Ta film is the mixture of α- and β-phases with amorphous-like structure. Increasing the N concentration of amorphous TaN underlayer successfully leads upper Ta film to form pure α-phase. For the practical application, the electrical property and reliability of Cu interconnection structure have been investigated by utilizing various types of Ta/TaN diffusion barrier. The diffusion barrier fabricated by the combination of crystallized α-Ta and TaN with high N concentration efficiently reduces the KRc and improves the EM resistance of Cu interconnection structure. Wei-Lin Wang, Chia-Ti Wang, Wei-Chun Chen, Kuo-Tzu Peng, Ming-Hsin Yeh, Hsien-Chang Kuo, Hung-Ju Chien, Jen-Chi Chuang, and Tzung-Hua Ying Copyright © 2015 Wei-Lin Wang et al. All rights reserved. The Influence of Thermal Conditions on V2O5 Nanostructures Prepared by Sol-Gel Method Wed, 01 Jul 2015 06:45:53 +0000 This work presents the result of structure investigations of V2O5 nanorods grown from thin films and powders prepared by sol-gel method. To examine the best temperature of nanorods crystallization, thin films deposited by spin-coating method on quartz glass or silicon substrates and bulk xerogel powders were annealed at various temperatures ranging from 100°C to 600°C. The structure of the samples was characterized by X-ray diffraction method (XRD), scanning electron microscope (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and mass spectroscopy (MS). The rod-like structure of V2O5 was obtained at 600°C on both quartz glass and silicon substrates and also from the bulk xerogel. The growth process and the effect of annealing treatment on the nanostructure are briefly discussed. M. Prześniak-Welenc, M. Łapiński, T. Lewandowski, B. Kościelska, L. Wicikowski, and W. Sadowski Copyright © 2015 M. Prześniak-Welenc et al. All rights reserved. Mesoporous Silica-Supported Sulfonyldiamine Ligand for Microwave-Assisted Transfer Hydrogenation Wed, 01 Jul 2015 06:38:30 +0000 N-Sulfonyl-1,2-diamine ligands, derived from 1,2-diaminocyclohexane and 1,2-diaminopropane, were immobilized onto mesoporous SBA-15 silica. The SBA-15-supported sulfonyldiamine-Ru complex was prepared in situ under microwave heating at 60 W for 3 min. The prepared sulfonyldiamine-Ru complex was used as an efficient catalyst for the transfer hydrogenation of ketones to the corresponding secondary alcohols. The heterogeneous complex showed extremely high catalytic activity with 99% conversion rate under microwave heating condition. The complexes were regenerated by simple filtration and reused two times without significant loss of activity. Shaheen M. Sarkar, Md. Eaqub Ali, Md. Shaharul Islam, Md. Lutfor Rahman, S. S. Rashid, M. R. Karim, and Mashitah Mohd Yusoff Copyright © 2015 Shaheen M. Sarkar et al. All rights reserved. Spectral Monitoring CH/C2 Ratio of Methane Plasma for Growing Single-Layer Graphene on Cu Wed, 01 Jul 2015 06:15:03 +0000 Single-layer graphene was grown on copper at a low temperature of 600°C by plasma-assisted thermal chemical vapor deposition. Its growth mechanism was discussed with reference to the emission spectra of the plasma. The methane plasma produces the active species (Hx, CHx, and Cx) without the addition of flowing hydrogen, and the amounts of hydrogen-containing species can be controlled by varying the plasma power. The effective distance was found between the plasma initial stage and the deposition stage for the single-layer graphene synthesis. The results reveal that high-quality graphene can be synthesized using methane plasma at a suitable plasma power. Shih-Hao Chan, Shih-Fang Liao, Hung-Pin Chen, Hung-Sen Wei, Sheng-Hui Chen, Cheng-Chung Lee, and Chien-Cheng Kuo Copyright © 2015 Shih-Hao Chan et al. All rights reserved. Superior PSZ-SOD Gap-Fill Process Integration Using Ultra-Low Dispensation Amount in STI for 28 nm NAND Flash Memory and Beyond Mon, 29 Jun 2015 12:41:28 +0000 The gap-fill performance and process of perhydropolysilazane-based inorganic spin-on dielectric (PSZ-SOD) film in shallow trench isolation (STI) with the ultra-low dispensation amount of PSZ-SOD solution have been investigated in this study. A PSZ-SOD film process includes liner deposition, PSZ-SOD coating, and furnace curing. For liner deposition, hydrophilic property is required to improve the contact angle and gap-fill capability of PSZ-SOD coating. Prior to PSZ-SOD coating, the additional treatment on liner surface is beneficial for the fluidity of PSZ-SOD solution. The superior film thickness uniformity and gap-fill performance of PSZ-SOD film are achieved due to the improved fluidity of PSZ-SOD solution. Following that up, the low dispensation rate of PSZ-SOD solution leads to more PSZ-SOD filling in the trenches. After PSZ-SOD coating, high thermal curing process efficiently promotes PSZ-SOD film conversion into silicon oxide. Adequate conversion from PSZ-SOD into silicon oxide further increases the etching resistance inside the trenches. Integrating the above sequence of optimized factors, void-free gap-fill and well-controlled STI recess uniformity are achieved even when the PSZ-SOD solution dispensation volume is reduced 3 to 6 times compared with conventional condition for the 28 nm node NAND flash and beyond. Chun Chi Lai, Yi Wen Lu, Hung Ju Chien, and Tzung Hua Ying Copyright © 2015 Chun Chi Lai et al. All rights reserved. A Stable Carbon Nanotube Nanofluid for Latent Heat-Driven Volumetric Absorption Solar Heating Applications Mon, 29 Jun 2015 12:25:32 +0000 Recently, direct solar collection through the use of broadly absorbing nanoparticle suspensions (known as nanofluids) has been shown as a promising method to improve efficiencies in solar thermal devices. By utilizing a volatile base fluid, this concept could also be applied to the development of a direct absorption heat pipe for an evacuated tube solar collector. However, for this to happen or for any other light-induced vapor production applications, the nanofluid must remain stable over extended periods of time at high temperatures and throughout repetitive evaporation/condensation cycles. In this work, we report for the first time a nanofluid consisting of plasma-functionalized multiwalled carbon nanotubes (MWCNTs) suspended in denatured alcohol, which achieves this required stability. In addition, optical characterization of the nanofluid demonstrates that close to 100% of solar irradiation can be absorbed over a relatively small nanofluid thickness. Nathan Hordy, Delphine Rabilloud, Jean-Luc Meunier, and Sylvain Coulombe Copyright © 2015 Nathan Hordy et al. All rights reserved. The Efficient Apoptotic Induction of Paclitaxel-Loaded Poly(N-vinylpyrrolidone)-block-poly(ε-caprolactone) Nanoparticles in the In Vitro Study of Lung Cancer Cell Lines Mon, 29 Jun 2015 11:26:49 +0000 Paclitaxel (Ptx) has been established as one of the most important components of first line chemotherapy regimen in the treatment of lung cancer. However, the poor solubility of Ptx makes it employ Cremophor as a solvent, which greatly limits its application due to the severe adverse effect. Encapsulation of Ptx into nanoparticles substantially increases the solubility of Ptx, therefore eradicating the necessity of Cremophor involvement. Here we report on a simple way of preparing Ptx-loaded nanoparticles formed by amphiphilic poly(N-vinylpyrrolidone)-block-poly(ε-caprolactone) (PVP-b-PCL) copolymers. Ptx was incorporated into PVP-b-PCL nanoparticles with a high loading efficiency. In vitro release study shows that Ptx was released from the nanoparticles in a sustained manner. The following experiments including cell staining and cytotoxicity tests indicated that Ptx-NPs led to enhanced induction of apoptosis in non-small-cell lung cancer cell lines NCI-1975 and A549, which is achieved by regulating the expression of apoptosis related proteins. Therefore, data from this study offers an effective way of improving the anticancer efficiency of Ptx by a nanodrug delivery system with amphiphilic PVP-b-PCL as drug carriers. Donghui Zheng, Huiping Ye, Can Luo, Huae Xu, and Ling Meng Copyright © 2015 Donghui Zheng et al. All rights reserved.