bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Atmospheric Corrosion of Zinc Magnesium Aluminum Coated Steel
Authors: Thierry Dominique , Persson Dan , Luckeneder Gerald , Stellnberger Karl-Heinz 
Published: February 2020

Hot dip galvanized steel and zinc alloyed coated steel such as ZnAl and ZnAlMg (ZM) are used in the building industry and in the automotive industry. However, In the case of zinc coated steel with Al and Mg, there is still relatively scarce information on the long term performance under atmospheric weathering conditions. Although large efforts have been made to study the corrosion products formed on zinc under atmospheric weathering conditions (see for instance reference 1 and 2), very few data exist on HDG and zinc alloyed coated steel [5]
This work is a part of a larger research program were steel with different zinc coatings are exposed on a worldwide basis on well characterized exposure sites in Europe, Asia and North America, see table 1. Corrosion rates of hot dip galvanized steel and zinc magnesium aluminum (e.g. 2% w% of Al and 2w% of Mg) coated steel were determined after 1, 2 and 4 years of exposure under different climatic conditions.
The formation and development of corrosion products was followed by detailed analysis of samples exposed 0.5, 1, 2 and 4 years using XRD, FTIR-spectroscopy and SEM-EDS. For HDG the sulphate/carbonate ratio was highly dependent on the exposure site (with low values at marine sites and high values at industrial sites). A model of initiation and propagation of local corrosion on HDG has been proposed. The analyses of corrosion products on ZM coated steel revealed higher sulphate/carbonate ratio compared to HDG. This may be linked to the corrosion rate of the coating with less formation of hydrozincite.
The data are discussed in view of current knowledge in atmospheric corrosion of zinc, HDG and ZM coated steel materials [1-6]

Table 1. Test sites in the exposure program

Code

Name

Country

Distance to Sea(m)

A

Brest
France
<5

B

Bohus-Malmön (I)
Sweden
<5

C

Bohus-Malmön (II)
Sweden
300

D

Ijmuiden
Netherlands
2600

E

Cadiz
Spain
750

F

Jiangjin
China
̴900 km

G

Ostrawa
Czech Republic
̴500 km

H

Dubai
UAE
2000

I

Daytona Beach
USA
100

J

Quindao
China
10

K

Wanning
China
100

L

Bangkok
Thailand
35 km

M

Sattahip
Thailand
10

N

Singapore
SIngapore
10

References
1-I. Odnevall, C. Leygraf, Corros. Sci. 34 (1993) 1213–1229.
2- I. Odnevall, C. Leygraf, Corros. Sci. 36 (1994) 1551–1567.
3- N. Le Bozec, D. Thierry, M. Rohwerder, Dan Persson, G. Luckeneder and L. Luxem, Effect of CO2 on the atmospheric corrosion of ZnMgAl coated steel, Corrosion Science, 74, pp 379-386, 2013

4- E. Diller, B. Lescop, S. Rioual, G Nguyen, D. Thierry and B. Rouvello, Initial formation of corrosion products on pure zinc and MgZn2 examined by XPS: Corrosion Science 79, pp 83-88, 2014.
5- D. Persson, N. Le Bozec, T. Prosek, D. Thierry, G. Luckenader , Corrosion Science Vol 90, pp 276-283, 2015.
6- D. Persson, D. Thierry, N. Le Bozec: Corrosion products formation on Zn55Al upon exposure in marine atmosphere, Corrosion Science, 720, 2011.
Characterization of Ti-Based Foams for Biomaterials Applications
Authors: Sancy Mamié , Aguilar Claudio , Lascano Sheila , Guerra Carolina , Vejar Nelson 
Published: February 2020

Development of titanium foams with low elastic modulus has increased its scientific and technological relevance due to the evident need to avoid the stress shielding problems related to stiffness mismatch with respect to bone. In this work we studied the synthesis and characterization of foams of pure Ti which present high potential for biomedical applications. Foams were obtained using NaCl (40, 50 and 60 %v/v), with particle size ranging from 150 to 350 mm, as space-holder. Powders and space-holder were mixed together and compacted under 200 to 800 MPa stress. NaCl particles were removed from the green compacts by submerging samples in distilled water at 60 °C (5 cycles of 4h). The green compacts were sintered at 1300 °C for 3 h in Ar atmosphere. Ti-based foams were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, optical microscopy. In addition, electrochemical impedance spectroscopy (EIS) measurements were performed under potentiostatic conditions at the corrosion potential in Ringer solution. Results showed that Ti-based foams with tailored heterogeneous pore distribution may be obtained using space holder method. Using theoretical models the elastic modulus of foams was estimated between 10 and 25 GPa. The experimental EIS data revealed a CPE behavior of the foams for all exposure time studied. Not significant effect was observed in the impedance modulus at low frequency range (|Z|LF) for low compaction stress. However, the |Z|LF decreased markedly for higher compaction stress, which could be related to the increase of the stress raiser. From our results, we conclude that foams with 50 and 60 % of porosity are potential bone replacement materials due to their stiffness closer to human bone value.
Ackowledgements: The authors are grateful to Fondecyt Grant 1160604 and 1161444
Evaluation of Titanium Carbide Thin Film Coatings on Surface Microstructure Controlled WC-Co
Authors: Tanaka Chihiro , Saito Takeyasu , Okamoto Naoki , Suzuki Soichiro , Kitajima Akira , Higuchi Koji 
Published: February 2020

Chemical vapor deposited (CVD) or physical vapor deposited (PVD) hard coating technique is widely used the cemented-tungsten carbide (WC-Co) for molds and cutting tools, which plays an important role in a lot of manufacturing industry. For example, titanium carbide (TiC), titanium nitride (TiN) and titanium carbonitride (TiCN) is one of the candidates to control surface properties in order to increase lifetime or to decrease friction coefficient of molds, tools and so on.
The film prepared by thermal CVD carried out around 1000°C has good uniformity and mechanical properties, which restricts substrates having low melting points, and also causes deformation of substrates. High temperature sometimes results in decarbonization of WC-Co surface which causes a significant decrease in toughness and transverse rupture strength. Plasma enhanced chemical vapor deposition (PECVD) or PVD has some merits as lower deposition temperature (< 500°C) than thermal CVD and high through-put, however, the film usually has low adhesion strength. Then, life of molds and cutting tools obtained PVD are sometimes shorter than that with CVD.
In this study, Several surface pretreatment methods were investigated to remove Co from the WC-Co surface and to increase surface roughness to enhance adhesion strength. The procedure include, Dry etching by CF4 plasma for 15 to 120min in the substrate temperature range from R.T. to 500°C. Chemical treatment with aqua regia (3HCl:HNO3) for 5 min at 25 to 60°C. After pretreatment, TiC coatings were formed by sputtering with TiC target or by PECVD from TiCl4/CH4. Surface roughness was evaluated by AFM. Crystallographic structure of WC-Co and TiC was evaluated by XRD. Hardness was evaluated by dynamic nanoindenter. Atomic concentration was determined by XPS.
Figure 1 shows maximum height roughness (Rz) and arithmetic average roughness (Ra) of WC-Co substrates after pretreatment. Rz and Ra got larger as increasing temperature of treatment conditions. In particular, substrate surface with aqua regia treatment at 60°C disappear Co peak.
Scratch test for PVD TiC coating on pretreated substrate revealed that critical load was larger than that with the film on non-pretreated substrate. When Ra was 150 nm, critical load was over 30N. The pretreated substrates surface by CF4 plasma and aqua regia have similar Ra value as 150 nm, however, the film with CF4 plasma exhibited no delamination and the film aqua regia exhibited delamination. The opposite trend could be due to the micro-level morphologies. The differences between PVD and CVD films will be discussed.

Figure 1
Substitutionally-Doped Intermediate Band Absorbers of Readily Tunable Composition
Authors: McCarthy Robert , Weimer Matthew S. , Haasch Richard , Schaller Richard D , Adam Hock S. , Martinson Alex B. F. 
Published: February 2020

Intermediate band photovoltaics (IBPV) attempt to significantly increase photovoltaic efficiency by absorbing more photons to produce additional photocurrent without sacrificing significant photovoltage. Through creation of a density of states within the parent semiconductor gap, a partially filled intermediate band (IB) may be used as a stepping stone to allow photons with sub-band gap energy to be absorbed and generate extractable charge carriers in a two-part absorption process. Sandwiching the IB material between selective n- and p-type contacts (or the parent semiconductor) excludes this Fermi level from the contacts, thereby theoretically preserving the full photovoltage of the parent material. This design theoretcially increases the maximum efficiency of a solar cell from 40.7 to 63.2% (assuming a large concentration factor).
Substitution of V into In2S3 to form V0.25In1.75S3.00 is predicted to produce nearly ideal properties to maximize efficiency under concentrated sunlight, with a band gap of 2.1 eV, and an intermediate band 0.70 eV above the valence band. While powders of this material have been fabricated previously, we report the V
x
In(2–x)S3 thin films. Atomic layer deposition (ALD) is ideally suited to its fabrication as compositional doping/substitution can often be simply and reproducibly achieved with simple precursor pulse sequence control. This is in contrast to many physical deposition methods in which the source composition is fixed by the target allow for composition changes when the deposition rate of each element is nonequal. We utilize an oxygen-free process for growing In2S3 but periodically incorporate a novel vanadium precursor in place of the indium precursor to achieve continuous compositional control over V and In. The physical, optical, and electrical intermediate band properties as well as photoelectrochemical performance of the V
x
In(2–x)S3 films will be presented.
The figure shows the absorption coefficients for VxIn(2–x)S3 films as a function of the doping level x.

Figure 1
A Novel Poly(acrylonitrile)-Based Quasi-Solid-State Electrolyte for Dye-Sensitized Solar Cells
Authors: Su Yi-Han , Teng Hsisheng 
Published: February 2020

The use of volatile liquid electrolytes limits the practical application of dye-sensitized solar cells (DSSCs) because of stability issues. Gel-type electrolytes have shown promising results in terms of cell stability and efficiency. Poly(acrylonitrile) has been known for its high ion solvation ability and structural stability.1 Herein, we report a quasi-solid-state DSSCs (QS-DSSCs) using gel polymer electrolyte (GPE) based on poly( acrylonitrile-co-methyl acrylate) (i.e. P(AN-co-MA)) dissolving a iodide-acetonitrile solution. The MA group rotates freely on the polymer chain to effectively coordinate the electrolyte solution into the polymer matrix.2By adjusting the polymer content, we can control the gelation time of the GPE for smooth electrolyte injection into the cells. No filler is needed to expedite the gelation process.
The QS-DSSCs exhibit higher short-circuit currents than liquid-state DSSCs (L-DSSCs). The polymer chains may have adhered to the TiO2films in the QS-DSSCs to suppress charge leakage and promote the photocurrent. However, the QS-DSSCs have smaller fill factors than the L-DSSCs, likely due to lower ionic conductivity of the GPE relative to the liquid electrolyte. Using the N719 dye as the sensitizer, the QS-DSSCs have a power conversion efficiency of 9.5 % whereas the L-DSSCs show a similar efficiency of 9.6 %.
Importantly, the proposed QS-DSSCs presented considerable improvements in long-term stability when subjected to accelerated aging. This developed GPE has presented a promising potential to replace liquid-state electrolytes used in DSSCs.

References

1. C. L. Chen, H. S. Teng, Y. L. Lee, J. Mater. Chem. 21 (2011) 628.
2. C. W. Tu, K. Y. Liu, A. T. Chien, C. H. Lee, K. C. Ho, K. F. Lin, Eur. Polym. J. 44 (2008) 608.

Acknowledgments: This research was supported by the Ministry of Science and Technology, Taiwan (104-2221-E-006-231-MY3, 104-2221-E-006-234-MY3, 105-3113-E-006-005, and 104-3113-E-006-011-CC2), and by the Ministry of Education, Taiwan, The Aim for the Top University Project to the National Cheng Kung University.
Thermal Stability of CuInSe2 solar Cell with Sputter-Zn(O,S) Buffer Layer As a Bottom Cell
Authors: Yu Hye-Jung , Wi Jae-Hyung , Lee Woo-Jung , Cho Dae-Hyung , Han Won Seok , Kim Seong-Yeon , Kim Jun-Ho , Chung Yong-Duck 
Published: February 2020

The power conversion efficiency of solar cells with multiple sub-cells in a tandem device can be extended beyond the Shockley-Queisser limit for a single-junction device, shifting the absorption onset to longer wavelengths and reducing thermalization losses. Theoretical calculations have been reported that the optimum band-gaps of absorber materials for a series-connected two-junction are 1.72 eV for the top cell and 1.14 eV for the bottom cell, respectively. The CuInSe2 (CIS) solar cells are well suited to be used as bottom cell in tandem solar cells. In case of monolithic tandem solar cell, Cu(In,Ga)Se2 based-cells with CdS buffer layer are quite vulnerable to high temperatures above 200oC, destroying the p-n junction by the diffusion of Cd atoms. Thus, the thermal stability of buffer layer prepared on the absorber of bottom cell should be important factor in solar cell performance.
In this study, we fabricated CIS solar cell with sputtered-Zn(O,S) buffer layer as a bottom cell because Zn-based buffer layer has a higher thermal stability as compared with CdS buffer layer. The completed solar cells were heated up to temperatures of 200 - 400oC for 60 min under vacuum in order to trace the degradation of cell performances. To investigate the interface quality and degradation mechanism after post-annealing process, the drive-level capacitance profiling and admittance spectroscopy have being applied as an analytic tool, which gives an information on bulk defect states, carrier density and defect energy at p-n junction. The temperature dependent current density-voltage measurements were also performed in the dark, red and white light from a solar simulator. These results clearly present that there is clear correlation between thermal stability and solar cell performance.
Enhanced Photovoltaic Effect in Single-Wall Carbon Nanotube/BiFeO3 Heterostructure
Authors: Lee Ho Jin , Kim Hyo-Sun , Seo Young-soo , Choi Taekjib 
Published: February 2020

Photovoltaic effect in ferroelectric materials have been revisited with energy applications because of visible-light-absorbing ferroelectrics and an anomalous photovoltaic effect, such as extremely large, above-band-gap voltages and polarization-induced electron-hole separation. BiFeO3, having a relatively low band-gap (~2.7 eV) is a potential visible-light-absorbing photoferroelectric materials. However, it is still limited to further enhancing photovoltaic efficiency due to a low photocurrent. In this work, we report an enhanced photovoltaic effect in single-wall carbon nanotubes (SWCNTs)/BiFeO3 photovoltaic heterostructures. High-purity metallic (M)- and semiconducting (S)-SWCNTs were seperated by using gel chromatography method and BiFeO3 thin films were grown on Nb:SrTiO3 substrate by pulsed laser deposition. M- and S-SWCNTs thick films are incorporated onto BiFeO3 for photovoltaic devices. For single BiFeO3/Nb:SrTiO3, we observed clear switchable diode and photovoltaic effects depending on ferroelectric polarizatioin directions. The S-SWCNTs/BiFeO3/Nb:SrTiO3 heterostructrues exhibited a large enhancement of photovoltaic performance compared with those of BiFeO3/Nb:SrTiO3 or M-SWCNTs/BiFeO3/Nb:SrTiO3. This heterostructure allowed a strong built-in field to be generated at the interface or the ferroelectric layer to efficiently separate photogenerated charge carriers and a wide range-light absorption due to near infrared-light absorbing S-SWCNTs and visible-light-absorbing BiFeO3. Under light illumination, this junction showed short-circuit current density of 1.73 mA/cm2 and open-circuit voltage of 0.21 V. Furthermore photovoltaic response was influenced by BiFeO3 thickness and SWCNT’s character. Our result implied that the heterostructure of high purity S-SWCNTs and high quality ferroelectric thin films could provide a route to highly efficient Photovoltaic devices.
(Invited) Innovation and Challenges of 3-D NAND Flash Technology
Authors: Kim Ki-Seog , Kim Jin Woong , Jin Kyo-Won 
Published: February 2020

NAND Flash has been improved by increasing the bit cost competitiveness and performance and enlarged its range of applications. Especially this cost reduction and performance improvement let the NAND Flash demand be increasing rapidly in the SSD applications. Needs of the market is demanding a high capacity and high speed of the NAND Flash for the information increase and exchange. Needs of these markets could be satisfied by implementation of a continuous scale down and multi bit. But 2D NAND Flash is not only faced with the difficulty of the scale down in a confined space, showing even marginal situations quality and performance secured in accordance with the scale down. 3D NAND Flash was able to break through the limit of the two-dimensional space by the vertical arrangement of cells in three-dimensional space. In this paper, we look at the critical technical elements for the vertical arrangement of 3D NAND Flash Cell and consider innovation and technology challenges of those elements.
3D NAND Flash meets the demand of the high density memory of the market by increasing the cell number per unit area with the increase of vertical stacks. This paper reviews the necessary stack number to meet the needs of the market and considers increasing the difficulty of the pattern formation increase with the high aspect ratio by increasing the stack height. . It also reviews some attempts to overcome the difficulty of the pattern formation for an effective bit cost reduction.
3D NAND Flash is there a big difference in electrical characteristics of 2D NAND Flash. First, we will compare the difference of the main characteristics of 3D NAND Flash and 2D NAND Flash. And we will look at the changes and challenges of the main electrical characteristics depending on the Stack increase for increased bit Cost reduction.
Double Layers-Stacked 3D 1D1R Crossbar Rram Integrating a Diode Selector with Rectification Ratio of ~109
Authors: Yoon Kyung Jean , Yoo Si Jung , Park Tae Hyung , Kwon Yeong Jae , Kwon Dae Eun , Hwang C. S. 
Published: February 2020

The F2-cell sized 1diode-1resistive switching memory (1D1R) crossbar accompanied by excellent rectifying characteristics is presented. Each diode and memory comprising the 1D1R is fabricated at room temperature, which is optimized for the integration of stacked layers excluding the thermal disruption issues over repetitive stacking procedures. The maximum rectifying ratio of 1.4x109 (at the reading voltage 2V) in the low resistance state of RS memory was achieved in a planar 2x2 um2 crossbar, which is the highest value for the rectifying ratio obtained in the RS memory devices reported to date, and enough to apply in ultra-high density CBA of up to 1Gb. A reliable memory operation with the window of ~103 - 104 based on unipolar RS phenomenon in the TiO2 switching layer is observed from operation current of a few hundred μA for set and a few mA for reset process, respectively, which means relatively lower operation power compared to those in the previously reported TiO2 URS system.The structural and chemical analysis for such low power, highly rectifying property based on SEM, TEM, EDS, XRD was also provided. Furthermore, Resistive switching random access memory (RRAM) operation of erasing, programming, and reading a selected cell not being interrupted by sneak currents from neighboring cells was demonstrated in a 4x4 crossbar array with double-layers 3D stakced device structure.
The Origin of Traps Responsible for Localization and Charge Transport in Memory Devices
Authors: Gritsenko Vladimir A. 
Published: February 2020

High-κ dielectrics are used now in ReRAM, FeRAM and charge trap (TANOS) flash devises. In present report the nature of deep traps responsible for the charge transport in the most important high-κ dielectrics of flash devices is considered [K.A. Nasyrov and V.A. Gritsenko, J. Appl. Phys.
109, 097705 (2011); V.A. Gritsenko, T.V. Perevalov and D.R. Islamov, Physics Reports
613, 1-20 (2016)].
The charge transport in high-κ dielectrics is controlled by electron and hole traps. In HfO2 charge transport is controlled by trap assisted tunneling between traps [D.R. Islamov, V.A. Gritsenko, C.H. Cheng and A. Chin, Appl. Phys. Lett.
105, 222901 (2014)] (Fig.1). Thermal trap energy in HfO2 is equal to 1.25 eV. The trap nature in HfO2 was studied with luminescence experiments. Blue luminescence band near 2.7 eV has excitation energy at 5.2 eV (Fig.2). Absorption peak of oxygen vacancy in HfO2 has equal energy as blue band excitation. Hence, the 5.2 eV excitation peak and 2.7 eV luminescence band are related to oxygen vacancies [T.V. Perevalov, V.Sh. Aliev, V.A. Gritsenko et al., Appl. Phys. Lett.
104, 071904 (2014)]. The photoluminescence Stokes shift (5.2-2.7)/2=1.25 eV is equal to thermal trap energy (Fig.3). So, the oxygen vacancy in HfO2 is the electron trap [V.A. Gritsenko, T.V. Perevalov and D.R. Islamov, Physics Reports
613, 1-20 (2016)].
Similar experiments were made for Al2O3, ZrO2, Hf0.5Zr0.5O2, Si3N4. It was concluded that in HfO2, Al2O3, ZrO2, HfZrO2 the oxygen vacancies are electron and hole traps. In Si3N4 the Si-Si bond is responsible for electron and hole localization and the charge transport [V.A. Gritsenko, Electronic structure of traps in silicon nitride for flash memory devices, chapter in book“Thin Films on Si: Electronic and Photonic Applications”, accepted for publication by “World Scientific Press”, 2016].

Figure 1