bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Pretreatment on the Electroless Metallization of Stereolithography Resins
Authors: Bernasconi Roberto , Alagna Leone , Magagnin Luca 
Published: February 2020

One of the most attractive techniques currently under development in the sector of additive manufacturing is the 3D printing of metallic objects. Parts realized with pure metals or alloys present many useful functional and aesthetic properties: electrical and thermal conductivity, metallic luster, high mechanical properties. Many techniques, including selective laser sintering (SLS) or electron beam melting (EBM), are able to yield good quality results [1]. All metal 3D printing techniques are however characterized by common drawbacks that limit their applicability: poor surface quality, residual porosity and inability to reach extremely low feature sizes (useful in the so called additive microfabrication).
Another approach that can be followed to obtain parts presenting metallic properties is the surface metallization of polymeric 3D printed objects. Polymers are easier to print than metals and some techniques, like stereolithography, are able to reach micrometric feature sizes. Metallic layers can be in principle applied using many different techniques, but electroless plating in particular presents important advantages in terms of cost per unit and flexibility.
Methods to electroless metallize stereolithography printed parts are available in literature [2], but the influence of different pretreatment routes on the quality of the final metallic layer was never fully investigated. In the present work, three stereolithography resins were pretreated following three different methods. The first one was based on the use of an acidic etching solution, the second was based on an alkaline etching, while the latter saw the application of atmospheric plasma to the pretreatment of the resins. Evolution of surface properties for the different pretreatment routes was investigated employing SEM, contact angle measurements, compositional analysis and FT-IR. Following surface preparation, resins were metallized with electroless copper. By doing this, the influence of the pretreatment on coating quality and adherence was evaluated.
[1] I. Gibson, D. W. Rosen, B. Stucker, Additive manufacturing technologies, Springer (2010)
[2] R. Bernasconi, C. Credi, M. Tironi, M. Levi, L. Magagnin, Electroless Metallization of Stereolithographic Photocurable Resins for 3D Printing of Functional Microdevices. J. Electrochem. Soc. 164, B3059–B3066 (2017)
Influence of Temperature on Peculiarities of Electroless Copper Deposition
Authors: Norkus Eugenijus , Stalnioniene Irena , Stalnionis Giedrius , Tamašauskaitė-Tamašiūnaitė Loreta 
Published: February 2020

The industrial electroless copper plating solutions containing formaldehyde as reducing agent are known from the middle of the last century and are widespread in the practice up to now. They are widely used in electronics for deposition of metallic copper layers on semiconductors or dielectrics (silicon wafers, resins etc.). Since such kind solutions are alkaline (formaldehyde is strong enough reducing agent for Cu(II) only in alkaline solutions), ligands are needed for preventimg of formation of Cu(OH)2 precipitate and binding Cu(II) into complexes
Ethylenediaminetetraacetic acid (EDTA) is one of the most widely used ligand in alkaline electroless copper plating baths due to its perfect chelating properties. The possible solution equilibria in alkaline Cu(II)-EDTA-formaldehyde solutions are discussed in details.
The data on use of EDTA in electroless copper plating as a Cu(II) ligand are enough wide-ranging, but, it is worth noting that practically all data are obtained at room or higher temperature. Therefore in this work copper coatings were deposited from alkaline formaldehyde-containing solutions, using EDTA as Cu(II) ligand at temperatures, mainly lower than room temperature.
The experiments were carried out in electroless plating solutions at pH 12.0 - 13.0 and 5 - 30 °C temperature during 0.5 and 1h (Fig. 1). The thickness of the compact copper coatings obtained under optimal operating conditions in 1 h can reach ca. 4 μm, depending on the pH and temperature. The maximum values of plating rate are reaching at pH 12.5 at all investigated temperatures. The real surface areas (R
f) of deposited copper coatings vary widely, i. e. from ca. 3.1 up to 39.3. The maximum R
f values were obtained at pH 12.0 for investigated temperatures.
The anodic formaldehyde oxidation measurements were carried out in formaldehyde solution at pH 12.5. It was found, that the rate of formaldehyde anodic oxidation depends on conditions of the formation of copper coatings – the highest rate of HCHO oxidation was determined on the surface’s electrolessly obtained at 5 °C and pH 13.0.

Acknowledgment

This research was funded by a Grant (No. LAT-12/2016) from the Research Council of Lithuania.
Co-Mn Oxide Electrodeposition for High Temperature Solar-to-Thermal Energy Conversion Systems
Authors: Cetina Dorantes Marco , Lizama Tzec Francisco Ivan , Oskam Gerko 
Published: February 2020

Solar concentration systems use solar collectors consisting of a metal tube with a selective coating, and an evacuated, glass vacuum tube to minimize losses by convection, conduction and thermal emission. The glass tubes eventually loose the vacuum, and the exposure to air results in degradation of the selective coating. Manganese cobalt oxides are alternative air-stable selective coatings, related to the spinel structure they form, which is stable up to high temperatures. The optical properties of the selective coating are expected to depend on the proportions of Co, Mn and O in the material; hence, the electrodeposited film needs to be optimized by tailoring the composition.
In this work we report on the combinatorial electrodeposition of Co-Mn oxides employing a Hull cell, in order to prepare a compositional materials library and to relate the composition with the solar absorptance and thermal emittance. The Co-Mn oxide material library was deposited in galvanostatic mode using a two-electrode setup, with a stable anode and stainless steel cathode (AISI 304). The electrodeposited cathodes were treated at 600 oC for a short time in order to complete the oxidation of the material. The solar absorptance and thermal emittance in the 200 nm - 15 µm range were obtained from reflectance measurements. From the best optical values, the current density corresponding to the optimal position on the cathode was selected for further characterization of the deposited material. Co-Mn oxide films were then deposited on 6 cm x 4 cm stainless steel substrates for thermal tests at 252 oC for 600 hours in order to evaluate the performance criteria. The film composition was obtained from energy-dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), and X-ray diffraction (XRD).
Electrochemical 3D Printing with Nanopipettes
Authors: Momotenko Dmitry , Zambelli Tomaso , Vörös János 
Published: February 2020

Nanopipette-based electrochemical methods rapidly develop into highly versatile and powerful tools in nanoscience for a variety of applications from imaging and sensing to nanoscale fabrication. Herein, we present advanced three-dimensional printing approaches for the fabrication of complex features using state-of-the-art nanopipette-based scanning probe techniques. Hollow cantilevers for atomic force microscope (AFM), known also as FluidFM probes,1 and pulled double-barrel glass capillaries are employed for precise local delivery of precursor species using pressure-controlled fluid flow and fluxes given by electrophoretic migration of ions. The intrinsic advantage of these concepts is the automated feedback mechanism, based either on the detection of mechanical forces (FluidFM) or on variation of ionic current through the nanopipette, that allows to maintain a constant distance (typically, from a few to several tens of nanometers) between the probe and a growing printed feature. This ensures precise control of the electrodeposition process and enables rapid fabrication of high-aspect ratio features at rates approaching hundreds of nm s-1. These new techniques open avenues for the architecture of a variety of features using continuous deposition and voxel-by-voxel printing strategy,2 and also enable in situ read-out of the printed patterns thanks to the primary functionality of nanopipette methods as scanning probe microscopy tools.3

References

1. Hirt et al., RSC Adv., 5, 84517 (2015)
2. Hirt et al., Adv. Mater., 28, 2311 (2016)
3. Momotenko et al., ACS Nano, 10, 8871 (2016)
(Invited) Room Temperature Wafer Bonding of Wide Bandgap Semiconductors
Authors: Mu Fengwen , Wang Yinghui , Suga Tadatomo 
Published: February 2020

Si power devices are quickly approaching their limits due to the intrinsic material properties. Wide bandgap semiconductors with the potential to allow significant performance improvement of power devices became very promising. With numerous studies and successive breakthroughs in recent years, wide bandgap semiconductors in term of material and device fabrication technologies have achieved huge advances. For example, large-size single crystalline substrate, high-quality epitaxial layer on hetero/homo substrate, and various power devices have been commercially available [1]. However, it is still very far to make the best use of the devices’ potential at low cost due to the difficult fabrication process and the expensive substrate. New innovative fabrication technologies are urgently desired. Wafer bonding, as one key technology capable of novel structure formation, efficient fabrication, device integration and cost reduction, is expected to be able to solve many problems in the fabrication of next-generation power device [2].
However, most of the previous wafer bonding of wide bandgap semiconductors need an annealing process at high temperature, even higher than 1000oC, which would limit its application in device fabrication. A well-developed low temperature wafer bonding method for wide bandgap semiconductors is still absent [3]. In this paper, our recent progress on the wafer bonding of wide bandgap semiconductors at room temperature would be introduced.

References

H. Okumura, MRS Bull., Vol. 40, pp. 439-444, 2015.

S. H. Christiansen, R. Singh, and U. Gosele, Proc. IEEE, Vol. 94, No. 12, pp. 2060-2106, 2006.

F. Mu, K. Iguchi, H. Nakazawa, Y. Takahashi, M. Fujino, R. He, and T. Suga, Appl. Phys. Express, Vol. 9, pp. 081302:1-4, 2016.
Ion Sieving Effect of Pillared Graphene Materials in Electrochemical Capacitors
Authors: Banda Harish , Daffos Barbara , Dubois Lionel , Taberna Pierre-Louis , Simon Patrice , Crosnier Olivier , Duclairoir Florence 
Published: February 2020

Electrical double-layer capacitors (EDLCs), commonly known as supercapacitors, store energy through reversible adsorption of electrolytic ions on the charged electrode surfaces.1 Extensive work on carbide-derived carbons (CDCs), ACs and templated carbons revealed that the sub-micro pores (< 1 nm) contribute significantly to the overall charge storage.2
,
3 Carbon materials with uni-modal pore size distribution curves (PSD) are essential for such a focused analysis.4 However, the difficulties in synthesizing such carbon materials and obtaining their PSDs reliably through gas sorption have hampered the progress.5 Meanwhile, research on graphene derivatives for charge storage in SCs has shown promising advances owing to good surface areas and electrical conductivities. However, much of the current research is devoted to improving the material porosity with a focus on PSDs, similar to the research on ACs.6 Surprisingly, little attention has been devoted towards exploring the possible confinement of the electrolytic ions into the unique layered structures of graphitic materials. An analysis of materials with varied inter-graphene sheets distance (d-spacing) in SCs would assess the possibility of such confinement.
In this context, this study is aimed at understanding the consequences of interlayer spacing on electrochemical charge storage. A class of graphene-like materials with varying d-spacing have been synthesized using alkyl diamines cross-linking and are characterized for their application in SCs. Electrochemical analysis of the materials in SCs using electrolytes containing tetraalkylammonium cations of different sizes (alkyl: ethyl, propyl, butyl and hexyl) showed limitations of ion adsorption in different materials. The PSD curves of the materials show no presence of sub-micro pores (< 1 nm) and thus relate the observed ion limitation to d-spacing. Hence, this work demonstrates that the inter-layer galleries in graphene like materials indeed confine electrolyte ions based on the size constrictions. A correlation between the d-spacing and the electrolyte ion sizes is established and a condition for maximum capacitances versus d-spacing for a specific electrolyte is being investigated.
[1] Simon, P.; Gogotsi, Y. Nat Mater 2008, 7 (11), 845–854.
[2] Merlet, C.; Péan, C.; Rotenberg, B.; Madden, P. A.; Daffos, B.; Taberna, P.-L.; Simon, P.; Salanne, M. Nat. Commun. 2013, 4, 3701-3707.
[3] Raymundo-Piñero, E.; Kierzek, K.; Machnikowski, J.; Béguin, F. Carbon 2006, 44 (12), 2498–2507.
[4] Kondrat, S.; Pérez, C. R.; Presser, V.; Gogotsi, Y.; Kornyshev, A. A. Energy Environ.
Sci. 2012, 5 (4), 6474–6479.
[5] Béguin, F.; Presser, V.; Balducci, A.; Frackowiak, E. Adv. Mater. 2014, 26 (14), 2219–2251.
[6] Li, C.; Shi, G. Adv. Mater. 2014, 26 (24), 3992–4012.
Nano-Engineering of 2D Materials for Supercapacitors
Authors: Zhu Yachao , Simon Patrice , Favier Frederic 
Published: February 2020

Exfoliation/restacking of 2D materials has recently been considered for the preparation of nanostructured electrode materials for supercapacitors. This approach consists in rebuilding new electrode materials from exfoliated layers of 2D materials either by restacking layers of different materials, by wrapping 3D materials with exfoliated layers, after chemical/morphological modification of those layers... with the aim of taking advantages of synergistic effects from distinct but complementary intrinsic behaviors together with the specific morphology of the resulting material. This can be, for example, to associate a 2D conductive material with a 2D pseudocapacitive material, eventually resulting in a more powerful nanocomposite electrode material [1]. This can also be about associating Faradaic layered double hydroxides (LDHs), for energy density, to more stable and powerful pseudocapacitive MnO2 [2], or opening a new macro/meso -porosity in Mxene layers for enhanced diffusion of electrolytic moieties in the reconstructed material.
This paper will present our most recent results gained while exploring these various approaches.

References

[1] Z. J. Fan , J. Yan , T. Wei, L. J. Zhi, G. Q. Ning , T. Y. Li, F. Wei, Adv. Funct. Mater. 211, 2011, 2366
[2] W. Quan, C. Jiang, S. Wang, Y. Li, Z. Zhang, Z. Tang, F. Favier, Electrochimica Acta, 2017, 247, 1072
(Invited) Patterning of Embedded STT-MRAM Devices: Challenges and Solutions
Authors: Berry Ivan , Park Jongchul , Kim Jongkyu , Min Benjamin , Lill Thorsten , Vahedi Vahid 
Published: February 2020

Ion Beam Etching (IBE) is emerging as the technology of choice for patterning of advanced embedded MRAM devices (<40nm CD, <1:1 aspect ratio) for 28nm logic integrated circuits. Experimental and simulated etch data, for a representative STT-RAM structure with 38 to 45 nm CD and 150 to 200 nm pitch, show a reduction in the sidewall re-deposition when operating at high angle and high ion energy. Ion energies above 1000eV provide best profile performance in the main etch. However, this leads to intermixing of stack materials and device shorts. Ion energies below 100eV are used in an overetch step to remove the intermixed layer. Excellent beam divergence and energy spread over the entire ion energy range are paramount and requires co-optimization of of the ion beam source and grid. To avoid damage of patterned MgO by air exposure, IBE and encapsulation PECVD must be integrated on one vacuum platform.
Sub 1ppm short fail patterning results have been obtained with optimized IBE and encapsulation processes.
Chromium(III) Sensor Using Ion Selective Membrane Immobilized on FET for Ground Water Pollution
Authors: Shahim Suman , Sukesan Revathi , Hsieh Ching-Yen , Wang Shin-Li , Wang Yu-Lin 
Published: February 2020

Anthropogenic industrialization related activities contribute to rising concentrations of heavy metal in the environment. This unprecedented deterioration of water quality by industrial effluents raises severe global health concern to both humanity and the ecosystem. Chromium, the 21st most abundant element on the earth’s crust, is extensively used in steel manufacturing, leather tanning, electroplating, paint and alloy manufacturing industries. The effluents released pollute water with Cr(III); classified as a group III carcinogen causing genotoxicity to flora and fauna. Hence water quality monitoring by detecting heavy metal concentration in tap water, canned liquid food items, etc will be of immense application if the sensor is affordable and equipped with simple user interface. Conventional methods like ICP-MS and AAS demand time, expense and complex equipments which are beyond the scope of daily use.
This work reports detection of Cr(III) employing Field Effect Transistor with Ion Selective Membrane on the gate electrode.The gate metal is extended and terminates in a two sensing electrode configuration modified with Poly Vinyl Chloride based sensing material.It is composed of an ionophore which binds with target analyte; consequently leading to a change in the transistor drain current. High sensitivity, selectivity and fast response time were observed in the pH range 3- 5 beyond which Cr forms hydroxyl complexes.The effective voltage at gate dielectric is a function of the concentration of Cr(III) ions in the test solution dropped on the sensing membrane. The device exhibits increasing trend of current gain with increase in concentration of the target ion as depicted in the plot. Hence, our simple novel biosensor can be calibrated to realize a cost effective, portable device to measure concentration of Cr(III) in real time drinking water quality monitoring or be integrated into food processing systems or even in medical diagnostics.

Figure 1
(Invited) Advanced Crystallization Using Blue Laser-Diode Annealing for Low Temperature Poly Si TFTs
Authors: Noguchi Takashi , Okada Tatsuya 
Published: February 2020

Laser Crystallizations using Blue Laser-Diodes Annealing (BLDA) as well as conventional Excimer Laser Annealing (ELA) are discussed for mounting the TFTs on flexible panels.
On glass, high crystallinity of Si films can be obtained by using multi-shots ELA as well as CW laser scanning [1, 2]. There are some issues for Si film after ELA, such as rough Si surface or shots MURA including the fabrication cost. As a result of scanning BLDA for thin Si films, remarkable crystallization occurs with keeping the surface smooth not only for CVD film but also for sputtered Si film [3]. By changing the laser power of 445 nm beam, the grain size can be controlled from micro-grains to large grains as well as to anisotropic long crystal grains [4]. For the Si films of heavily phosphorus doped condition, the resistivity decreased drastically due to the increase in the carrier mobility with high carrier concentration after BLDA of single beam scanning as well as after multi-shots ELA [5].
To realize high performance poly Si films directly not only on flexible glass [6] but also on flexible plastic sheet, effective laser annealing for high quality Si film by low temperature deposition is expected and a design for the thermal buffer layers on flexible sheet is effective [7]. To perform ultra-low temperature TFT process, metal source/drain structure without using ion implantation is also proposed.
High performance poly Si TFTs with low fabrication cost on flexible panel should be possible not only for n-channel but also for p-channel [8, 9].

References

M. Tai, M. Hatano, S. Yamaguchi, S. K. Park, T. Noda, M. Hongo, T. Shiba and M. Ohkura, Proc. of AM-LCD, TFT3-3, p.231 (2002)

T. Noguchi, Mat. Res. Soc. Symp. Proc., 557, p.213 (1993),

T. Okada, K, Sugihara, S. Chinen and T. Noguchi, J. Korean Phys. Soc., 66, No.8, pp.1266-1269 (2015). .

T. Noguchi, J. Inf. Display, 11, No.1, p.12 (2010).

T. Noguchi and T. Okada, J. of Inf. Display, 15, No.1, p.47 (2014).

T. Harada, F. Gakiya, Y. Ishiki, T. Okada, T. Noguchi, K. Noda, A. Suwa and H. Ikenoue, Proc. of IDW, AMDp2-11L, p.444 (2016).

T. Okada, J.D. Mugiraneza, K. Shirai, T. Suzuki, T. Noguchi, H. Matsushima, T. Hashimoto, Y. Ogino and E. Sahota, Jap. J. Appl. Phys. 51, 03CA02 (2012).

K. Sugihara, K. Shimoda, T. Okada and T. Noguchi, J. Inf. Display, 18, No.4, 173-176 (2017).

T. Ashitomi, T. Harada, T. Okada, T. Noguchi, O. Nishikata and A. Ota, J. Inf. Display, 18, No.4, 185-189 (2017).
(Invited) Chemical Phenomena at Interfaces between Battery Cathodes and Electrolytes
Authors: Cabana Jordi 
Published: February 2020

Controlling the reactions occurring at electrode-electrolyte interfaces is key to long-lasting energy storage technologies, such as Li-ion batteries, especially when pushing voltages of operation to increase their energy density. Extreme potentials reached at the electrodes in a fully charged battery render them too reactive toward the electrolyte, triggering deleterious decomposition reactions. While the description of products resulting from electrolyte decomposition has been an object of study for decades, the definition of reactions at the cathode side of the interface is less extensive. The cathodes in a battery are composed of transition metal oxides, which are known to present a rich redox chemistry. During this talk, tools employed to track the structure and chemistry of the surface of cathode particles vis-à-vis their electrochemical properties will be presented. Particular emphasis will be placed on X-ray absorption spectroscopy, a technique with surface specificity that probes redox chemistry. The results revealed that side reactions on the electrolyte are synchronized with the redox processes at the oxide surface, which ultimately lead to the dissolution of transition metal ions into the electrolyte.
Classical strategies to prevent these undesired reactions and increase electrode durability generally involved post-synthetic coatings of the cathode powders or the use of electrolyte additives. More recently, new effective options have been added through the demonstration, in our group, of core-(epitaxial) shell architectures at the level of primary particles. Yet the description of the exact modes of degradation and the means by which these strategies are effective remains elusive. The use of objects of study designed at the highest definition and fidelity, in the form of highly dispersed nanocrystals with conformal shells, enhances the understanding of these interfacial phenomena. The high fidelity ensures coherence in the data and the representative character of the characterization methods, especially when highly local probes are employed. The interplay between understanding of electrode-electrolyte processes and the design of novel cathode architectures will be discussed.