bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrical Characterization of Dry and Wet Processed Interface Layer in Ge/High-K Devices
Authors: Ding YI Ming , Misra Durga , Bhuyian Mdnasiruddin , Tapily Kandabara , Clark Robert D. , Consiglio Steven , Wajda Cory S. , Leusink Gert J. 
Published: February 2020

Even through Ge/high-k interface has been extensively studied the high leakage current associated with these gate stacks continues to introduce frequency dispersion and hysteresis in capacitance-voltage (CV) and conductance-voltage (GV) characteristics. These dispersions severely limit the understanding the interface and accurate estimation of interface state density, Dit
and equivalent oxide thickness (EOT). Since several parameters like EOT, flatband voltage, bulk doping, surface potential as a function of gate voltage are important and bulk defect and interface defect concentration affect the CV and GV characteristics several corrections to the characteristics are required to obtain accurate values.
We have measured the CV and GV characteristics of Ge/ALD 1nm-Al2O3/ALD 3.5nm-ZrO2/ALD TiN MOS capacitors with three different interface treatments by HP4284 LCR meter using different frequencies. The interface treatments are (i) simple chemical oxidation (Chemox); (ii) chemical oxide removal (COR) followed by 1 nm oxide by slot-plane-antenna (SPA) plasma (COR&SPAOx); and (iii) COR followed by vapor O3 treatment (COR&O3). The plots were corrected by three different methods. Firstly, we removed the effect of sheet resistance, RS
. The second approach uses data (capacitance and conductance) measured at two different frequencies to solve two unknown variables (capacitance and conductance) (1). The solved CV plot is closer to the corrected CV plot at 1 MHz rather than that at 100 KHz. This allows us to use 1MHz corrected data to obtain the EOT information. Additionally, this approach helps to verify that 1MHz data is robust assuming that defects do not respond to the other frequencies used here. The third approach is to modify the measurement circuits (2) to enhance CV and GV characteristics. Fig. 1 shows the CV characteristics after the corrections by three different approaches for three different samples. COR&SPAOx samples show excellent CV characteristics. The details of all the correction methods and the advantages of these methods to correct CV and GV will be discussed. We will demonstrate that the correction methods are suitable for accurately measure the interface characteristics. The Dit
calculated by two method (conductance and capacitance spectroscopy) (Fig. 2) are compared and discrepancy of the results between different samples and different methods will be explained.

References

Y. Ding and D. Misra, J. Vac. Sci. Technol. B, 33, 021203, 2015.

K.J. Yang and C. Hu, IEEE Trans on Electron Dev, 46(7), 1500, 1999.

K.S.K Kwa, S. Chattopadhyay, N.D. Jankovic, S.H. Olsen, L.S. Driscoll, and A.G. O'Neill, Semicond. Sci. Technol., 18(2), 82, 2003.

Figure 1
(Invited) Electronic Properties of Self-Assembled Trimesic Acid Monolayer on Graphene Layers
Authors: Shayeganfar Farzaneh 
Published: February 2020

The adsorption of trimesic acid (TMA) on graphene surface has been studied with density functional theory (DFT). By considering the adsorption of a single TMA molecule on different sites on graphene, we have been able to perform a detailed analysis of the equilibrium geometry, charge transfer, electronic properties in terms of density of states and band structure, and finally scanning tunnelling microscopy (STM) simulations on those simple systems. The results for isolated adsorption were then compared to the behaviour of TMA unit within two different self-assembled monolayers. Our results indicate that structural deformations of TMA may significantly contribute to the magnitude of p-doping and band gap opening in graphene. The formation of an hydrogen bonding network within the assembly improves the stability of the adlayer but its adhesion on graphene is significantly lowered. The magnitude of p-doping in graphene per TMA unit remains nearly constant from the isolated to the assembled systems, but the magnitude of the band gap opening appears strongly correlated with the breaking of symmetry of $\pi$-states of graphene by the TMA patterning on the surface. Our results suggest that polymorphism in self-assembled adlayers could be used to tune and control the electronic properties of graphene.\\
\emph{Keywords}: Tunable band gap; Electrical field; Ab-initio calculation; Electronic properties;
Using Copolymers As Suppressors in a Copper Plating Bath for through-Hole Filling
Authors: Wen Shih-I , Dow Wei-Ping 
Published: February 2020

Recently, a copper electroplating technique, namely butterfly technique (BFT) [1], was developed to achieve a void-free filling of a through hole (TH) of a printed circuit board (PCB). However, the BFT for TH filling caused an issue of thick copper layer on the PCB surface, which increases the process cost due to a requirement of post copper etching process. Literature has mentioned that copolymers have strong suppression on copper electroplating than poly(ethylene glycol) (PEG). The strong suppressor can minimize surface copper thickness to achieve excellent filling performance. In this work, we employ a copper filling formula to perform the TH filling. Several copolymers were employed as suppressors to replace PEG. The result shows that the surface copper thickness is decreased by using the copolymer. It can not only enhance the copper filling performance but also increase plating efficiency.
Reference

W. P. Dow, H. H. Chen, M. Y. Yen, W. H. Chen, K. H. Hsu, P. Y. Chuang, H. Ishizuka, N. Sakagawa, R. Kimizuka, “Through-Hole Filling by Copper Electroplating”, Journal of The Electrochemical Society, 2008, 155, D750-D757.

Figure 1
(Invited) Development of Bimetallic Electrocatalysts and Electrodes for Carbon Dioxide Electrolysis Via Direct Deposition Strategies
Authors: Carroll Kyler , Hsiao Yung Wei , Brown Steven , Su Liang , Brushett Fikile R. 
Published: February 2020

The development of energy efficient carbon dioxide (CO2) electroreduction processes would simultaneously curb anthropogenic CO2 emissions and provide suistainable pathways for fuel generation. If such electroreactors employed CO2 feedstocks from major emission sources (e.g., thermal power plants) and excess electricity from intermittent locally-available renewable resources (e.g., solar, wind), then chemicals of economic value could be generated in a carbon neutral fashion [1]. While significant efforts have been focused on heterogeneous CO2 electroreduction to various products including carbon monoxide (CO), formic acid, and methanol; to date, no process has been able to demonstrate both high energetic efficiencies and high current densities [2]. A key challenge in the development of active, selective, and stable electrocatalysts is translating performance nanomaterials to appropriate electrodes which augment catalyst activity by maximizing surface area, facilitate species transfer, and minimize undesirable side reactions [3,4].
Direct deposition (e.g., electrodeposition, galvanic replacement) of nanostructured electrocatalysts onto microporous metal foam electrodes may offer a pathway to high performance electrodes. Metal foams hold two key advantages: (i) their porous nature facilitates extended tunable electrochemical interfaces without sacrificing transport of reactants and ions; and (ii) they can act as a conductive substrates for the direct deposition of active materials eliminating the need for conductive additives and binders [5]. Further, as many active metals can form foams, surface alloys and multi-metallics could be created through deposition and annealing. This talk will focus the development of Au/Cu and Ag/Cu core/shell catalysts via galvanic replacement reactions. First, we will discuss the synthesis, characterization, and performance evaluation of Cu nanoparticles / nanowires with a few Au or Ag monolayers. We will then describe the translation of these active materials to microporous Cu foam electrodes, subjected to various electrochemical pretreatments, which, in turn, will be evaluated in small-scale flow cells.

Acknowledgements

We gratefully acknowledge the financial support from the MIT Center for Materials Science and Engineering.

References

[1] D.T. Whipple, P.J.A. Kenis, J. Phys. Chem. Lett., 2010, 1, 3451-3458
[2] A.M. Appel et al., Chem. Rev., 2013, 113, 6621-6658
[3] H.R.M. Jhong, F.R. Brushett, P.J.A. Kenis, Adv. Energy Mater., 2013, 3, 589-599
[4] J. Wu, F.G. Risalvato, P.P. Sharma, P.J. Pellechia, F.-S. Ke, X.-D. Zhou, J. Electrochem. Soc., 2013, 160, F953-F957
[5] Y. Li, Z.-Y. Fu, B.-L. Su, Adv. Funct. Mater., 2012, 22, 4634-4667
Reaction Mechanism Analysis of a Li-O2 Battery: Structure of Electrode/Electrolyte Interface Probed Via Soft-x-Ray Absorption Spectroscopy, Hard x-Ray Photoelectron Spectroscopy, and in-Situ Hard x-Ray Diffraction
Authors: Yogi Chihiro , Kamiguchi Kazuhiro , Takao Naoki , Watanabe Takeshi , Kubobuchi Kei , Matsumoto Masashi , Ohwaki Tsukuru , Imai Hideto 
Published: February 2020

Rechargeable Li-air batteries have been attracting much attention because of their extraordinary high energy capacity, viz, theoretically it reaches more than ten-times than those of existing Li-ion secondary battery. Recent materials development, such as use of glyme-series electrolytes, effective electrodes (metal based catalysts and/or high surface area carbon materials with nitrogen doping), or use of Redox-mediators, is about to find realistic solutions to overcome long-term crucial issues of Li-air battery, such as large over-potential at charge process, electrolyte degradation due oxygen radicals, and low cycleabilty presumably caused by unstable electrode properties at both anodes and cathodes.
Thus, additional deeper information on the reaction mechanism, involving unwanted side reactions, could be expected to accelerate such improvement. In this context, we performed reaction mechanism analysis by utilizing various experimental techniques, such as in-situ time-resolved x-ray diffraction, soft x-ray absorption spectroscopy at Li, C, O, and S K-edges, and hard x-ray photoelectron spectroscopy (HAXPES), combined with other conventional laboratory analysis methods.
Charge/discharge tests of Li-O2 battery were performed by using standard coin-type or electrochemical cells under various conditions including impact of moisture to the reaction. Soft x-ray absorption spectroscopy measurements were carried out at SR center of Ritsumeican University (BL-11) and Aichi synchrotron radiation center (BL6N1). Hard x-ray photoelectron spectroscopy and in-situ hard x-ray diffraction measurements were performed at SPring-8 on beamlines BL46XU and BL19B2.
We observed formation and dissolution processes of Li2O2 via in-situ time-resolved hard x-ray diffraction, which exhibited non-linear behaviors reflecting difference of nature of deposited Li2O2 particles. Also we analyzed the structure and chemical compositions of interface between Li2O2 and/or carbon electrodes and electrolyte solutions via soft x-ray and hard x-ray spectroscopy. The result indicates the structure of interface is significantly affected by the operation condition, and consists of various species decomposed from electrolyte and/or Li-salts. More detailed discussion will be presented at the Meeting.
Progress Towards a Rechargeable Multivalent Battery
Authors: Lipson Albert L. , Proffit Danielle L. , Pan Baofei , Lapidus Saul , Liao Chen , Burrell Anthony K. , Vaughey John T. , Ingram Brian J. 
Published: February 2020

Cheaper batteries with higher capacity would increase the market penetration of electric vehicles and grid storage systems. One way to achieve these gains in battery performance is to utilize a metal anode such as lithium, magnesium or calcium. Lithium metal anodes have been extensively studied for decades, but still have not been commercialized. On the other hand, comparatively little research has been performed on magnesium or calcium systems. Magnesium metal has been shown to be less susceptible to the formation of dendrites than lithium. No one is yet able to plate and strip calcium, however, it does possess a lower voltage than magnesium and a non-passivating oxide. In order to rapidly explore the potential of these battery systems, we have developed techniques to study cathode materials without the need for a working metal anode. In doing this we have determined that corrosion issues are more severe in these electrolytes than their lithium counterparts. Furthermore, we have determined a class of materials that can intercalate Mg and Ca in nonaqueous electrolytes. These materials are characterized by a combination of techniques including energy dispersive X-ray spectroscopy (EDX), X-ray absorption near-edge spectroscopy (XANES) and X-ray diffraction (XRD) to prove intercalation of the multivalent ion. Additionally, we have made the first attempts to pair these materials with low voltage anode materials. These anode materials include using Mg metal and metallic anodes that react with the multivalent ion.
Sulfur Nanoparticles Coated with Polyelectrolyte Nanomembranes for Sulfur Cathode
Authors: Osada Naoki , Bucur Claudiu B , Muldoon John 
Published: February 2020

Elemental sulfur is the very attractive cathode for the post Li ion battery since the sulfur has high theoretical capacity of 1672 mAh/g1). Despite these attractive properties, practical application of Li-S battery is still unrealized by some big challenges on a sulfur cathode such as high resistance, low loading of active material and dissolution of the intermediate polysulfide into the electrolyte during charge and discharge. These issues cause low columbic efficiency, fast capacity fade and self-discharge of the Li-S battery. In order to suppress the dissolution of the intermediate polysulfides and minimize the addition of conductive carbon2); our group has created a controlled nanoarchitecture template in which sulfur nanoparticles encapsulated with the conductive polyelectrolyte nanomembranes coated with nanocarbon similar to “chocolate hazelnut truffle”3) (figure 1). The findings of this work will be discussed.
Figure 1. A three-dimensional view of our concept depicting the carbon infused sulfur core, the hollow carbon nanoparticles and multilayer selective polymer membrane decorated with functionalized carbon.

References
[1] Bruce, P. G., Freunberger, S. A., Hardwick, L. J. and Tarascon, J. –M., Nat. Mater., 11, 19-29 (2012).
[2] Bucur, C. B., Muldoon, J., Lita, A., Schlenoff, J. B., Ghostine, A. R., Dietz, S. and Allred, G., Energy and Environ. Sci., 6, 3286-3290 (2013).
[3] Muldoon, J., Bucur, C. B., Boaretto, N., Gregory, T. and N. di Vito, Polymers: Opening Doors to Future Batteries, Polymer Reviews, (2015, Accepted).

Figure 1
Ultra-Thin Film Solid-Oxide Fuel Cell Technology Development: Status, Challenges, and Opportunities
Authors: Tsuchiya Masaru 
Published: February 2020

Solid oxide fuel cell (SOFC) is one of the cleanest ways to convert chemical energy stored in fossil fuel into electricity. SOFC offers over 50 % electrical efficiency with low pollutant emission and low noise, and it can be utilized in various applications including portable electronics, remote power, and combined heat and power unit for homes. However, the technology has been under development for many decades, but not yet seen large scale commercialization due to issues in cost and durability.
SiEnergy Systems is developing low temperature ultra-thin solid oxide fuel cell that potentially offer major cost reduction and reliability improvement. The use of ultra-thin films reduces the amount of materials required in creating fuel cells, including rare-earth materials, therefore significantly reducing the material cost of the fuel cell. Additionally, the reduced thickness leads to the enhanced ionic conductance across the electrolyte, and enables SOFC operation at 350-550 °C, which is substantially lower than operating temperature of conventional SOFCs that is at 750 °C or above. SOFC operating at this temperature range avoids the disadvantages of conventional SOFCs, such as slow start-up time, costly materials and bulky thermal insulation, while potentially taking advantages of high energy conversion efficiency.
In this talk, recent advancement in thin film solid oxide fuel cell research and development will be reviewed with particular emphasis on electrode materials development and large-area cell demonstration.
Synthesis and Properties of a Multiblock Copolymer with Long Side Chains for Anion Exchange Membrane Fuel Cells
Authors: Kohl Paul A , Ahlfield John M. , Liu Lisha , Chu Deryn 
Published: February 2020

Anion Exchange Membrane (AEM) fuel cells are a possible route to overcoming fundamental issues with acid-based fuel cells. The issues include the high cost of platinum catalysts, complex water transport, and sluggish electrochemical reactions, etc. However, the performance of AEM fuel cells is not as good as that of Proton Exchange Membrane (PEM) fuel cells because of the limitations of current anion exchange membranes, such as low ionic conductivity, poor stability at high pH, and high water uptake.
A series of novel multiblock copoly(arylene ether)s with long side chains were synthesized for AEM fuel cells. The multiblock copolymers were synthesized by polycondensation of separately-prepared hydroxyl-terminated oligomers with fluoro-terminated oligomers. The resulting multiblock structure, in which one block is hydrophilic and one block is hydrophobic, was designed to ensure a nanophase-separated morphology. Multiblock copolymers with different block lengths and ion exchange capacities (IEC) were synthesized to maximize ion conductivity and explore the relationship between chemical structures and properties in anion exchange membranes. Furthermore, copolymers with long side chains exhibited higher stability in high pH environment than their counterparts without long side chains. The degradation mechanism was also studied for the long side chain block copolymers.
Financial support from US Office of the Deputy Assistant Secretary of the Army for Defense Exports and Cooperation (DASA-DE&C) is gratefully acknowledged.
Electrochemical Oxidation of Borohydride for Direct Fuel Cells
Authors: Grimmer Christoph , Grandi Maximilian , Zacharias Robert , Friedrich Theo , Hacker Viktor 
Published: February 2020

The direct borohydride fuel cell (DBFC) is gaining more and more interest in recent years because of high energy density and the easy handling of liquid fuels. The oxidation of the borohydride anions at the anode delivers up to eight electrons per molecule at a theoretical potential of -1.24 V vs. SHE [1,2]:
BH4
- + 8OH- → BO2
- + 6H2O + 8e-

In combination with an oxygen cathode and an alkaline membrane or electrolyte an electrochemical cell with a nominal voltage of 1.64 V is formed.
The electrochemical oxidation is investigated on various noble metal catalysts such as Pt/C, Au/C and Pd/C and bimetallic alloys thereof with first row transition metals. The electrochemical properties of the catalysts are characterized by cyclic voltammetry in alkaline electrolyte containing NaBH4 in standard three electrode configuration with a rotating disc electrode (RDE) [3].

Figure
1
: Cyclic voltammograms of Pt/C with 5mM NaBH4 on a RDE, anodic sweeps at 200, 400, 600, 900, 1200, 1600 and 2000 rpm.
The borohydride oxidation on Pt/C starts at around -50 mV vs. RHE getting diffusion limited at 200 mV vs. RHE with a complete eight electron transfer. Due to diffusion limitation data processing according to Levich and Koutecky-Levich is possible.

Figure
2
: Levich plot of Pt/C catalyst at 0.50 V vs. RHE (data from Fig. 1)

Figure
3
: Koutecky-Levich plot of Pt/C catalyst at 0.50 V vs. RHE (data from Fig. 1)
Levich and Koutecky-Levich (Fig. 2 and 3) analysis show an eight electron transfer reaction at a potential of 0.5 V vs. RHE in the diffusion controlled region and as well at 0.01 V vs. RHE in the kinetic controlled region.
Although platinum shows excellent catalytic activity towards borohydride electrooxidation, the main side reaction, namely the hydrolysis reaction is also catalyzed. Besides the loss of fuel, the formation of gaseous hydrogen can harm the electrode due to mechanical stress. This issue can be addressed by replacing platinum with less active catalysts. Gold based electrocatalysts for example do not catalyze the hydrolysis side reaction.
On the roadway towards a practicable application it is necessary to improve the selectivity at the anode catalyst system.

Acknowledgements

Support by NAWI Graz and financial support by the Austrian Federal Ministry of Transport, Innovation and Technology (BMVIT) and The Austrian Research Promotion Agency (FFG) through the program a3plus and the IEA research cooperation is gratefully acknowledged.

References

[1] E. Gyenge, Electrochim. Acta 49 (2004) 965.
[2] D. Finkelstein, N. Mota, J. Phys. Chem. C 113 (2009) 19700.
[3] M. Chatenet, M.B. Molina-Concha, N. El-Kissi, G. Parrour, J.-P. Diard, Electrochim. Acta 54 (2009) 4426.

Figure 1
Cathodoluminescence Studies of Phosphor Particles
Authors: Harris Paul Gregory , Engelsen Daniel den , Silver Jack 
Published: February 2020

Cathodoluminescence (CL) studies carried out in a field emission scanning electron microscope are reported. CL images of phosphor powders frequently manifested a bright ring around the periphery of the particles. Additionally, particles resting on top of others were noted to be substantially brighter than under-lying ones. Similar effects are often seen in secondary electron images and are usually ascribed to the electron beam spending more time in the surface region near the edges and therefore generating more secondary electrons close to the surface that are able to escape into vacuum. This explanation, however, does not explain why we see such effects in CL microscopy. To exclude the possibility of charging artefacts conductive ZnO:Zn phosphor powders (~1-2µm) were studied and these also exhibited the effect. Studies have been made of model systems with both luminescent and non-luminescent materials adjacent to one another and on the basis of these results the origins of these phenomena are believed to be due to the combined effects of electrons backscattered out of the crystals onto adjacent particles, together with light absorption by the substrate.
Figure 1. Cathodoluminescent micrograph of ZnO:Zn phosphor particles.

Figure 1
Thermal Properties of Mn4+-Doped Complex Fluoride Phosphors
Authors: Setlur Anant A , Murphy James , Garcia-Santamaria Florencio , Sista Srinivas 
Published: February 2020

Red phosphors based upon Mn4+-doped complex fluorides are currently being implemented in a variety of LED display and lighting applications. These phosphors can enable high CRI (for lighting) or high color gamut (for LCD backlit displays) without significant efficiency losses. However, the properties of these phosphors can significantly differ based upon the specific phosphor host. One example is in the temperature quenching of luminescence where T0.5, the temperature where emission intensity reaches 50% of the room temperature value. Different Mn4+-doped complex fluoride phosphors can have T0.5 values that vary by more than 100oC. In many applications, these differences in thermal quenching can prevent the use of these materials In this presentation, we discuss the various properties of numerous Mn4+-doped complex fluoride phosphors as a function of temperature. Correlations between composition, vibrational properties, and luminescence properties will be discussed and analyzed. Finally, the presence (or absence) of thermal quenching as a function of Mn4+ concentration will also be presented.