bluuebunny/crossref_metadata_2025 huggingface dataset:
An Examination of the Factors That Influence Primary Battery Longevity Performance Under Multiple-Cell Vs Single-Cell Testing Conditions
Authors: Joubert Jessica , Iveson Ray
Published: February 2020

Primary alkaline batteries still account for the vast majority of battery sales in the US. According to the test standards the American National Standards Institute (ANSI), primary alkaline cell longevity performance is intended to be measured by discharging individual cells under specific load and duty cycle conditions to prescribed cutoff voltages. However, market research studies indicate that greater than 90% of battery-driven devices in the US require more than 1 cell, in electronic series configuration, to function. Thus, the analysis of primary alkaline battery performance in multiple-cell configuration will yield results that are far closer to the battery performance observed in actual devices and, therefore, is more consumer relevant. Focusing on AA size batteries, multiple cells discharged in series configuration demonstrated consistently lower cell performance (measured in service hours) vs single cells discharged under similar load and duty cycle conditions. The magnitude of decrease in performance for any battery design was highly related to the performance variability exhibited in single cell performance testing. Additional factors that influenced the lower performance observed in multiple-cell testing included the number of cells in series, discharge load magnitude, load type, endpoint voltage and battery design characteristics such as rate of increase of polarization during discharge. The relative importance of these factors to multiple-cell performance was quantified along with consideration of the deficiencies of reporting primary battery performance based on single-cell performance testing.
Zinc Base Coatings, Their Challenges and New Strategies
Authors: Wijesinghe Sudesh Lakshitha , Yan Wenjin , Wu Linda Y L , Tan Yong Teck , Qian Min , Koh Chan Wai
Published: February 2020

Zinc based coatings are effective of protecting steel structures for various industrial applications due to their cathodic protection properties on top of the barrier protection. Hot dip galvanization was the most historical technique under this category. Despite of their historical background, using hot dip galvanization in some current applications has become questionable specially due to their inability to apply on site which reduces the productivity and adverse environmental consequences galvanization process may can cause. Zinc rich coatings trying to replace hot dip galvanization in these demanding applications though they have another set of industrial challenges to satisfy.

One such a demand is to cater aesthetic requirements, to provide coloured coating without compromising corrosion protection properties. Current practice is to apply a multi coat system which may contain three or more layers. Thus, based on the critical service related problems of current zinc based coatings, this work is focused to develop processes to provide an effective and reliable zinc based corrosion protective coating system which satisfy aesthetic requirements, aiming building and construction related applications.

To enhance the productivity compared to the current coating systems, it is expected to develop a single layer coloured zinc rich coating accommodating different corrosion protection strategies. Colouring pigment with suitable size distribution and chemical properties are studied for this development to fulfil the aesthetic purpose, while examining the effect of other additives to enhance the corrosion protection properties. Synergistic effect of different corrosion protection strategies is evaluated to review the suitability of the single colour zinc coating. Overall corrosion protection performance of the developed coatings is evaluated by methodologies based on scientific principles and international standards to get quantitative and qualitative details of coatings properties. Details of this development with evaluation results will be presented. Alternative solutions to cater industrial demands will also be discussed.
(Invited) To Stabilize the Interface between Li Metal and Li10SnP2S12 Solid Electrolyte By an in-Situ Formed Solid Electrolyte Interphase Layer with Ionic Liquid
Authors: Yang Yong
Published: February 2020

In spite of the extremely high ionic conductivity, the commercialization of Li10GeP2S12 (LGPS)-type materials is plagued by the poor stability against Li metal. Herein, to address that issue, a novel strategy has been proposed and demonstrated for the first time to in-situ modify the interface between Li metal and Li10SnP2S12 by employing ionic liquid additives. And the effects of lithium salt on the interfacial modification is further investigated too. X-ray photoelectron spectroscopy (XPS) results reveal that the addition of a small volume of 1.5 M LiTFSI/ N-propyl-N-methyl pyrrolidinium bis(trifluoromethanesulfonyl) imide (Pyr13TFSI) ionic liquid can form a stable SEI layer at the interface between Li and solid electrolyte simultaneously during cycling whereas the presence of LiFSI salt causes the enrichment of LiF in SEI layer and results in the higher resistance of the cell upon a long cycling life. A stable SEI layer instead of mixed conducting layer can prevent sulfide solid electrolyte from further decomposition and the Li/Li symmetric cell with 1.5 M LiTFSI/ Pyr13TFSI ionic liquid shows stable cycle performance for more than 1000 h with both the charge and discharge voltages reaching around 0.05 V at 0.038 mA cm-2.
Structural and Conductivity Mechanism of a Boron-Based Ionic Liquid Electrolyte for Magnesium Batteries
Authors: Pagot Gioele , Donà Edoardo , Bertasi Federico , Vezzù Keti , Nale Angeloclaudio , Negro Enrico , Di Noto Vito
Published: February 2020

In the last years, massive improvements have been achieved in the field of battery technology opening the door to more efficient electric vehicles and electric power storage. Nevertheless, further research is needed to overcome lithium drawbacks and enter in the such called “beyond Li-ion” technology [1]. In this perspective, magnesium secondary batteries are promising electrochemical storage devices due to their a) high volumetric capacity (3832 mAh·cm-3), b) great abundance and homogeneous spread of Mg in the Earth’s crust, c) safety and environmentally friendliness, and d) low standard reduction potential (-2.36 V). The main roadblock to the enter of these devices in the global market is the development of a safe and efficient electrolyte. In the last 3 years it has been demonstrated that electrolytes obtained by dissolving a suitable magnesium salt (δ-MgCl2) into ionic liquids (ILs) are able to efficiently deposit and strip magnesium with very low overpotentials and high current densities [2-4].

In the present work a new family of electrolytes is proposed, based on 1-Butyl-1-methylpyrrolidinium chloride and boron trichloride, doped with δ-MgCl2. The thermal stability and transitions of the proposed materials is studied using HR-TGA and MDSC. The structure and interactions of the materials are investigated by vibrational spectroscopies (FT-IR and confocal micro-Raman). Finally, Broadband Electrical Spectroscopy is exploited to elucidate the electric response of materials and to detect the long-range charge migration mechanisms of the electrolytes.

References

[1] V. Di Noto, S. Lavina, G.A. Giffin, E. Negro, B. Scrosati, Electrochim.
Acta,
57 (2011) 4-13.

[2] F. Bertasi, C. Hettige, F. Sepehr, X. Bogle, G. Pagot, K. Vezzù, E. Negro, S.J. Paddison, S.G. Greenbaum, M. Vittadello, V. Di Noto, ChemSusChem, 8 (2015) 3069-3076.

[3] F. Bertasi, F. Sepehr, G. Pagot, S.J. Paddison, V. Di Noto, Adv. Funct. Mat., 26 (2016) 4860-4865.

[4] G. Pagot, F. Bertasi, K. Vezzù, F. Sepehr, X. Luo, G. Nawn, E. Negro, S.J. Paddison, V. Di Noto, Electrochim.
Acta, 246 (2017) 914-923.
Electrochemical Properties of Li1.3Al0.3Ti1.7(PO4)3-Filled Composite Polymer Gel Electrolytes of Pvdf-HFP and Hydroxypropylcellulose
Authors: Kim Jumi , Oh Jimin , Shin Dong Ok , Kim Ju Young , Lee Young-Gi , Kim Kwang Man
Published: February 2020

The composite polymer gel electrolytes (CPGE) for lithium-ion batteries are prepared by combining poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) and hydroxypropylcellulose (HPC) as binary polymer components, Li1.3Al0.3Ti1.7(PO4)3 (LATP) as an inorganic filler, and 1 M LiPF6 dissolved in EC:PC:EMC as an electrolyte solution. The PVdF-HFP is included as a linear flexible polymer chain in the electrolyte medium, the rigid rod-like molecules of HPC has the lyotropic property between liquid crystalline and isotropic phases, and the LATP supports mechanical strength and also provides another conduction path in the gel medium [1] to increase ionic conductivity. The synergy among each component is expected to lead highly ionic conductive electrolytes with excellent mechanical strength. In this study, the electrochemical properties of LATP-filled CPGE are investigated and the charge-discharge performance of LiCoO2/graphite lithium-ion battery cell adopting the CPGE is also carried out. Through such the electrochemical investigations, the optimum amount of LATP showing the best performance would be mainly determined. Moreover, the low-temperature performance of the LiCoO2/CPGE/graphite cell would be particularly examined because the LATP(50 wt.)-filled CPGE (polymer 100 wt.) exhibits higher ionic conductivity (e.g., 4x10-3 S/cm) at low temperature (e.g., -10oC), compared with the CPGE without LATP (3.6x10-4 S/cm). In the presentation, how each component and its content contribute to the electrochemical performance of the cell would also be discussed in detail.

Figure 1
Electrochemistry in Non-Polar Media Enabled By New Lipophilic Salts
Authors: Abu-Lebdeh Yaser
Published: February 2020

There is little known about electrochemical behavior in non-polar media due to lack of compatible, lipophilic salts. [1] Herein, this difficult challenge has been overcome by following a strategy based on designing and synthesizing a novel family of organic salts with highly-delocalized cations and anions. The salts show good miscibility in heptane, an archetypical, non-polar media and the electrolyte solutions show peculiar ionic conductivities over the whole concentration range which enable their application as antistatic agents and also as new type of hydrophobic electrolytes in various electrochemical devices.[2]

[1] Y. Abu-Lebdeh, A. Hammami, A. Abouimrane, M. Armand, Electrochemistry Communications 81, 112-115, 2017.

[2] F. Bertasi, G. Giffin, K. Vezzù, G. Pace, Y. Abu-Lebdeh, M. Armand, Vito Di Noto, Physical Chemistry Chemical Physics 19 (38), 26230-2623, 2017.
Development of Novel Ionomer Electrolytes for Alkali Metal Batteries
Authors: Hänsel Christian , Kundu Dipan
Published: February 2020

Single-ion conducting electrolytes are an interesting alternative to liquid binary salt electrolytes, which are currently used in most batteries due to their high ion conductivity. However, the mobility of both cations and anions in these electrolytes results in an ion concentration gradient, and consequent polarisation losses. The ion concentration gradient is especially detrimental for alkali metal batteries. It causes inhomogeneous metal deposition leading to uncontrolled dendrite growth at the alkali metal electrode.1 Thus, it is necessary to eliminate the free movement of anions. One way to achieve that is by covalently tethering the anions to a polymer backbone. So called ionomers have achieved considerable success toward stabilising lithium metal deposition and preventing dendritic structure.2,3 By exchanging the counter ion these ionomers can be used in a wide range of different types of batteries. Here, we report on the synthesis and development of novel ionomers derived from inexpensive and chemically robust polymers. The microporous ionomer membranes infused with liquid achieve cation transference numbers close to unity, high ion conductivity (> 10-5 Scm-1 at room temperature) over wide temperature ranges, and good thermal and mechanical stabilities, see Fig. 1. Stable Na/Li plating stripping performance is achieved using the ionomer membrane.

Lin, D. et al.,

Nanotechnol.
2017, 12, 194–206.

Lu, Y. et al., Adv. Energy Mater.
2015, 5, 1402073.

Oh, H. et al., Mater., 2016, 28, 188-196.

Caption Fig.:

Fig 1: (a) Photograph and SEM image of the microporous ionomer membrane. (b) Arrhenius plot of the Na+ ion conductivity of the microporous ionomer membrane infused with EC/DEC (vol. 1:1).

Figure 1
Stability of Organic Reactants for Aqueous Flow Batteries
Authors: Goulet Marc-Antoni , Pollack Daniel , Tong Liuchuan , Tabor Daniel P. , Aspuru-Guzik Alan , Gordon Roy G. , Aziz Michael J.
Published: February 2020

The transition to non-emitting renewable energy requires cost-effective arbitrage on several timescales to balance the disparity between peak demand and the electricity supplied from intermittent renewables. Among the technologies available for grid scale energy storage, flow batteries have recently gained considerable interest for longer duration timescales because their energy and power costs are decoupled. With the aim of minimizing these energy costs, many researchers have shifted toward designing electrolytes with synthetic redox active organic molecules made from inexpensive and earth abundant materials. Within this trend, it has become evident that the calendar life, rather than the cycle life, of the organic compound is a limiting factor for the viability of many chemistries. We present here some examples connecting flow battery capacity fade to electrolyte stability. An in-depth analysis on the chemical stability and decomposition of one particular molecule, 2,6-dihydroxyanthraquinone, is presented and compared with other mechanisms of capacity fade observed for similar molecules. In most cases, symmetric cell cycling is used to assess the capacity fade and stability of single electrolytes and these results are linked to decomposition of electrolytes stored at elevated temperatures in both reduced and oxidized form.
(Keynote) Innovative Polymer Electrolytes for Secondary Lithium and Magnesium Batteries
Authors: Di Noto Vito , Vezzù Keti , Negro Enrico , Bertasi Federico , Pagot Gioele
Published: February 2020

The development of new electrolytes is a crucial target to devise secondary batteries running on alkaline- and alkaline-earth elements characterized by a high specific energy and power and an extensive cyclability, able to provide power for a wide range of applications ranging from portable electronic devices to electric vehicles. The electrolytes must satisfy very demanding requirements, including: (a) easy migration of the alkaline- and alkaline-earth cations between the electrodes of the battery; (b) high compatibility with all the other functional materials used in the assembly of the device; (c) wide potential window and excellent chemical stability.

This report summarizes the preparation and characterization of innovative families of electrolytes meant to address these issues and opens the way for future research trends in this field. The investigated materials comprise: (i) single-ion-conducting nanocomposite polymer electrolytes; (ii) solid-state single-ion-conducting polymers; and (iii) conventional polymer electrolytes.

In detail, the first approach comprises the study of nanocomposite polymer electrolytes (nCPEs) consisting of PEG400 and innovative lithiated fluorinated nanofillers (e.g., titanium or iron oxide) whose surface anion groups are neutralized with Li+ cations. These materials are single-ion conductors, and at room temperature they exhibit a Li+ conductivity higher than 10-5 S/cm. The second approach includes the investigation of Poly(vinyl alcohol)-based solid polymer electrolytes which are obtained by direct lithiation of partially hydrolyzed poly(vinyl alcohol), forming a lithium-poly(vinyl alkoxide) macromolecular salt. In this case it is possible to demonstrate a conductivity higher than 10-5 S/cm at RT upon plasticization with EMImTFSI ionic liquid.

Finally, Broadband Electrical Spectroscopy (BES) studies of classic polymer electrolytes and innovative Magnesium salts for secondary Mg batteries will be presented. This technique will allow for the detailed elucidation of the interplay taking place between structure and conductivity of in these systems, thus tailoring the design of future polymer electrolytes.

The chemical composition of the studied materials is analyzed by ICP-AES and microanalysis. The thermal properties are investigated by HR-TG and DSC measurements. The structure and the interactions in the materials are studied by vibrational spectroscopies (FT-MIR and –FIR). The electric response is elucidated by Broadband Electrical Spectroscopy (BES). Results allow to propose a conduction mechanism and to define the interplay existing between structural, thermal transitions and electrochemical properties of proposed innovative electrolytes.

Acknowledgement

This project has received funding from the BIRD 2016 program of UNIPD.
Environmentally Friendly Butyl, Benzyl and Ethyl Glycerol Carbonate Electrolytes for Room and High Temperature Energy Storage Applications
Authors: Salari Maryam , Zhang Heng , Grinstaff Mark W
Published: February 2020

The successful design of safer electrical energy storage devices must include the use of thermally stable, non-flammable, conductive electrolytes that perform at ambient temperatures as well as at higher temperatures [1-2]. Here, we report the synthesis of three glycerol carbonate (GlyC) solvents for use as electrolytes when combined with 1.0 M LITFSI in high voltage Li ion supercapacitors (LICs). The butyl, benzyl and ethyl glycerol carbonate (GlyC) solvents are non-flammable and stable up to > 125 oC. Conductivity is dependent on temperature and of the three solvents, the butyl glycerol carbonate solvent with 1.0 M LiTFSI exhibits the highest conductivity (4 mS/cm). The electrochemical performance and rate capability of the devices, prepared with each of the three electrolytes, were evaluated at room temperatures and at 100 oC. The butyl glycerol carbonate electrolyte allows safe operation at 100 oC with a notable specific capacitance of 115-162 Fg-1 as well as room temperature operation with a specific capacitance of 29 Fg-1. This finding is further supported by the observation of a 40 times increase in ionic conductivity at low temperatures by changing the side chain in the back bone of the glycerol carbonate from benzyl and ethyl to butyl leading to a significant improvement of the electrochemical performance (Figure 1).

References:

1- M. Salari, B. G. Cooper, H. Zhang, and M. W. Grinstaff, Synthesis of an Environmentally Friendly Alkyl Carbonate Electrolyte Based on Glycerol for Lithium-Ion Supercapacitor Operation at 100 °C. Advanced Sustainable Systems, 2017. 1(8): p. 1700067-n/a

2- X. Lin, M. Salari, L. M. R. Arava, P. M. Ajayan, M. W. Grinstaff, Chemical Society Reviews 2016, DOI: 10.1039/C6CS00012F.

Figure 1. (a) Ionic conductivity Profile as a function of temperature for synthesized carbonate solvents containing 1.0M LiTFSI. (b) Comparison of CV obtained for the synthesized electrolytes operated at 100 oC and a scan rate of 1000 mVs-1, demonstrating high temperature performance and rate capability of the synthesized glycerol carbonates.

Figure 1
(Invited) Electrodeposition of Equiatomic Fe-Ni Films
Authors: Lin Qiyuan , Zangari Giovanni
Published: February 2020

Current permanent magnets such as NdFeB contain a significant fraction of rare earths (Dy, Nd), resulting in an increasing cost and higher supply risk. Potential low cost substitutes include the L10 tetragonal structure of equiatomic Mn-Al and the L10 equiatomic Fe-Ni. While the former exhibits a relatively low energy product (~ 110 kJ/m3), the latter material may approach the energy product of Nd-Fe-B.

We have grown equiatomic Fe-Ni films by electrodeposition at both very low and very high growth rate, in order to understand the influence of the driving force for growth on the morphology and the defectivity of the films. A citrate/glycinate electrolyte with low metal ion concentration exhibited after annealing at 300 C a coercivity of 1000 Oe, which cannot be ascribed only to internal stresses. A sulfate based electrolyte with high metal ion concentration, suitable to achieve high growth rates, presents a large defect density. The talk will cover the synthesis and characterization of the materials, with emphasis on the crystal structure and the correlation between microstructure, phase and magnetic properties.
Evidence of a Magnetic Effect on the Electron Transfer of the Hydrogen Evolution Reaction (HER)
Authors: Knoche Krysti L. , Lee Heung Chan , Rathuwadu Nadeesha , Leddy Johna
Published: February 2020

In 1972, Trasatti carefully compiled the rates of hydrogen evolution reaction (HER) on 31 metal electrodes near pH 0 [1]. The HER is a surface reaction that can be represented as

Hsoln⁺ ⇌ Hads⁺

Hads⁺ + e ⇌ Hads

∙

2 Hads

∙
⇌ H2,ads

H2,ads ⇌ H2,soln

Trasatti also defined the electrochemical work function Φ, which is the energy needed to remove an electron from the electrode surface to a redox species immediately at the electrode surface. The rates of the HER reaction are embedded in the standard exchange current density j0 (A/cm2) that measures the standard heterogeneous rate of electron transfer, k0. Trasatti demonstrated that plot of log j0 versus Φ yields two parallel lines as shown, where regression yields

log j₀ = (6.4₄ ± 0.2₄) Φ (eV) - (35.₄±1.₁) with R² = 0.98 for the higher rate line and

log j₀ = (6.5 ± 0.5₆) Φ (eV) - (38.₅ ± 2.₄) with R² = 0.93 for the lower rate line.

The slopes are the same but the intercepts differ by 3. For a given Φ, metals on the upper line have HER rates that are 1000 x higher than metals on the lower line.

In this presentation, the magnetic properties of the electrodes are shown to describe the binary segregation of the data into two discrete lines. The magnetic properties of the electrodes are set by paired and unpaired electron spins. The results are evidence of a magnetic effect on electron transfer.

References

[1] Trasatti, S. Work Function, Electronegativity, and Electrochemical Behavior of Metals. III. Electrolytic Hydrogen Evolution in Acid Solution. Electroanalytical Chemistry and Interfacial Electrochemistry 39, 163-184 (1972).

Figure 1
Mask-Free Selective Metallization on Glass By Controlling Surface Hydrophilicity
Authors: Wang Kuan-Ting , Wei Tzu-Chien
Published: February 2020

The trend in selective metallization for printed circuit board (PCB) is to replace lithography process because of its process complication and cost waste. Nowadays, there are many ways to selective metal deposition, like ink-jet technique or laser irradiation for electroless metal deposition. In this study, we develop an unique, novel method to realize selective electroless metal deposition by controlling surface hydrophilicity without the need of tedious photomask process.

This technique is demonstrated by forming a superhydrophobic surface in the first step, and then laser patterning to allow bottom surface exposed. Those exposed surface was then metallized by a process involving “silane compound modification + nano-Palladium catalyst activation”. In particular, TiO2 nanoparticles is coated by spin-coating on the glass substrate. Then, the surface with TiO2 nanoparticles is modified by Perfluorooctyltriethoxysilane (PFOTES) in order to form a superhydrophobic surface. The water contact angle of the surface exceeds 150 degree at this stage. The superhydrophobic layer acts like a shelter that could prevent electroless plating reaction from the substrate surface. After that, laser beam is applied on the superhydrophobic surface to remove PFOTES/TiO2 so that the specific pattern is exposed. Finally, selective metallization is accomplished on the exposed surface using home-made Pd nanoparticles and commercial electroless metal solution.

Figure 1
Electrocatalytic Reduction of Carbon Dioxide Using Graphene/Cotmpyp-Based Coatings
Authors: Bochlin Yair , Korin Eli , Bettlehiem Armand
Published: February 2020

The sharply rising level of atmospheric CO2 is one of the largest environmental concerns facing our civilization today. CO2 is the most significant greenhouse gas that has major effects on the environment such as global warming and ocean acidification. The conversion of CO2 back to useful compounds is a critical goal that would restore balance to earth’s atmosphere. CO2 reduction is possible through chemical catalysis, electrochemistry, photochemistry and biological processes. Chemical catalytic processes generally operate at high temperatures and pressures which lead to high energy cost. Electrochemical methods, however, operate at ambient conditions which offer a simple and effective route for CO2 reduction.

The electrocatalytic capabilities toward CO2 reduction of some cobalt porphyrins have been reported in the literature, although at considerable overpotentials and low current densities. The present work aims to assemble an electrocatalytic system composed of cobalt porphyrins and graphene derivatives. Spectroscopic, microscopic and electrochemical methods are used to analyze the interactions occurring between such porphyrins and graphene derivatives, and their effect on CO2 reduction. Such self-assembled systems are formed between 5,10,15,20-Tetrakis(1-methyl-4-pyridinio) porphyrin (CoTMPyP) and graphene oxide (GO). This combination was electrodeposited on electrode surfaces, from aqueous solutions, using concessive cyclic voltammetry scans. Cross-section TEM-EELS images found dense distribution of CoTMPyP between the graphene sheets throughout the coating (figure 1). This arrangement of dense cobalt porphyrins between large conducting graphene sheets leads to enhanced electrocatalytic activity and formation of liquid-phase methanol as determined from GC-MS analysis.

The electrodeposited CoTMPyP-GO system showed increased electrochemical activity toward CO2 reduction vs. water reduction (0.7 and 0.3 mA/cm2, respectively, at -1.2V vs. Ag/AgCl), as examined in aqueous 0.1 M Na2CO3 solution at pH 11.5.

Figure 1
Interlayer Dielectric Bonding for 300mm Wafers
Authors: Fujino Masahisa , Kikuchi Katsuya , Takahashi Kenji
Published: February 2020

Nowadays, the large-scale integration process using 300 mm Si wafers is the main stream in the manufacturing process for commercial devices. Furthermore, wafer-level hybrid bonding technology is the key issue for the 3D high-density integration devices. For hybrid interface with metal and interlayer dielectric, both materials are required for the reliable connection. In particular, the interlayer dielectric layers have various materials and conditions in order to apply for each device such as SiO2 by thermal oxide, tetraethyl orthosilicate, or silane; SiN, quartz, and so on. The direct bonding technology has been investigated for several decades, and several bonding methods are applicable for the wafer-level bonding. In particular, surface activated bonding (SAB) method with Ar fast atom bombardment (Ar-FAB) or plasma activated bonding (PAB) are the essential technology for wafer-level hybrid bonding. In this research, several interlayer dielectric substrates were prepared on 300 mm Si wafers; SiO2 by thermal oxide, tetraethyl orthosilicate, or silane; SiCN, and the several process parameters including pre-process for the bonding has been investigated and evaluated their bonding quality. In this abstract paper, partial results are described: Thermal oxide SiO2 (100 nm thickness) wafers were bonded by PAB process. Bonded wafers were evaluated by C-mode scanning acoustic microscopy (C-SAM) for voids confirmation and blade strength measurement. (Fig.1) Also, the bonded interface has been observed by the cross-sectional transmission electron microscopy (TEM) observation. (Fig.2) At the interface of among the bonded wafers, there is only one void due to a particle intervening interface during bonding process. The peripheral unbonded area seems to correspond to the touched area by the transferring process. Furthermore, the cross-sectional TEM image shows the stable bonded interface without voids. In the conference program, we would like to present the each optimized bonding process for each ILD material cyclopaedically.

Figure 1
Si-Ge Heterostructures Fabricated by Room Temperature Wafer Bonding
Authors: Razek Nasser , Dragoi Viorel , Jung Arik , von Känel Hans
Published: February 2020

The newly developed technology EVG® ComBond® was used for the fabrication of Si-Ge heterostructures. In this technology, an ion beam bombardment is used to clean and to activate the Ge- and Si-surfaces at room temperature by removing the native oxides as well as organic contaminants without deteriorating chemical composition and microroughness of the surfaces.

After surface activation, the wafers were brought into contact at room temperature under high vacuum, which resulted in a wafer bond extending over the entire area.

The successful room temperature covalent bonding of Ge/Si with high bond strength (measured by the crack opening method), no micro-voids, and no thermal outgassing (inspection with scanning acoustic microscopy) was achieved. Cross-sectional transmission electron microscopy (TEM) of the bonded Ge/Si-interface revealed that the wafers bonded without damaging the crystal lattice except for a thin amorphous layer of <0.9 nm. This amorphous layer was completely removed by thermal annealing at 400°C for two hours. Current-voltage measurements on 1 cm2 samples made from p-Si/n-Ge wafer bonds revealed diode behavior with a ratio of forward to reverse current of >4 and a threshold voltage of around 0.3V. The forward current yields an ideality factor of 1.1 after correcting for the series resistance which consists of a contact and interface resistance.

Figure : High-resolution TEM image of Ge/Si interface after thermal annealing at 400°C for 2 hours shows no obvious oxide layer and amorphous layer between the wafers.

Figure 1
Modelling of Voltammetric Data from Electrochemical Capacitor Electrodes
Authors: Donne Scott W
Published: February 2020

Many techniques have been used to characterize materials used in electrochemical capacitor electrodes. This includes the suite of materials science techniques to assess material structure, morphology, conductivity, etc., as well as various electrochemical techniques to assess material and electrode performance and cycling mechanisms. In the domain of electrochemical characterization methods techniques such as cyclic voltammetry and constant current charge-discharge cycling are used commonly to assess performance and gain an introductory insight into electrochemical mechanisms. Other techniques such as electrochemical impedance spectroscopy and step potential electrochemical spectroscopy also provide substantial mechanistic information.

This work is focused on enhancing the information that can be extracted from voltammetric data on electrochemical capacitor electrodes. Contributions to the overall current response are made from:

1. Capacitive processes, as modelled using the series combination of a resistor and capacitor;

2. Kinetically limited processes, as modelled using the Butler-Volmer equation;

3. Solid state redox processes, as modelled using an experssion derived from the Nernst equation; and

4. Electrode resistance
An Activated Bio-Carbon for Electrochemical Double-Layer Capacitors
Authors: Kim Yong-Il , Kim Jong-Huy , Baek Jeong-Hun , Lee Chan-Woo , Yoo Jungjoon
Published: February 2020

An activated bio-carbon for electrochemical double-layer capacitor used commercialized potato starch powder as the starting material to produce high-purity spherical carbon using a hydrothermal synthesis method with various reaction times. Chemical activation of the KOH coated bio-carbon spheres was heat treatment from 700-900 °C. The activated bio-carbon activated at 900 °C exhibited as specific surface area of 1579.4 m2/g, average pore size of 2.9663 nm and pore size distribution was mostly concentrated in the range of 1.3–3.5 nm.

As results of the electrochemical characteristics for the electrode of activated bio-carbon synthesized for 12 hrs and activated at 900 °C, in 6 M KOH aqueous electrolyte, the specific capacitance variations were 160.6 F/g at 5 mV/s, 142 F/g at 100 mV/s, and 123.5 F/g at 500 mV/s.
(Invited) Atomic Layer Deposition and Etching of 2D Transition Metal Dichalcogenide Materials
Authors: Mane Anil U. , Choudhury Devika , Letourneau Steven , Elam Jeffrey W.
Published: February 2020

Ultra-thin layer of two dimensional (2D) materials mainly transition metal dichalcogenide (TMD) semiconductor possess exceptional properties such as electrical, optical, magnetic, mechanical and chemical. This allows the exploration of internal quantum degrees of freedom of electrons and their potential for use in optoelectronic, energy, and sensor applications. At present, research on 2D-layered TMDs mostly rely on (i) flakes produced by exfoliation from bulk, (ii) synthesis by high temperature (800-1000oC) mostly by chemical vapor deposition or (iii) solution based methods. Although exciting results are being obtained, but all these methods have limitations such as poor quality of the material, lack of precise control of thickness, interface or ability to integrate them into complex 3D devices. Nevertheless, the biggest challenge in realizing their full potential has been the lack of doable material synthesis methods of such films with high uniformity, conformality and interfacing with other materials such as oxides and metals.

Among the various thin film growth methods, atomic layer deposition (ALD) offers the best combination of a controlled layer-by-layer growth of the material with high conformality and suitable integration with other oxides such as dielectrics and metals. At the same time, precisely control thermal-based etching method for 2D-TMD materials are needed. Secondly at present, there are tremendous attention and efforts on development of the thermal vapor based well control etching methods especially on atomic layer etching (ALEt). The successful combination of both ALD and ALEt of 2D-TMD can pave the way to control the synthesis of 2D-TMD layers over large areas. This will be important for 2D-TMD material integration for future successful large-scale complex device structures fabrication.

Here we will first discuss the ALD growth of 2D-TMDs (e.g. MoS2, HfS2 and MgS2) on metals (e.g. Mo, W and TiN), dielectric oxides (e.g. Al2O3, MgO, HfO2, and TiO2) and vice versa. Then precise control etching processes based on molybdenum hexafluoride (MoF6) and H2O vapor will be discussed. The MoF6-H2O precursors based etching process offer several advantages including low cost, low processing temperature, rapid and effective etching spanning the range from continuous etching to atomic layer etching (ALEt). We have used in-situ quartz crystal microbalance (QCM) and Fourier-transform infrared spectroscopy (FTIR) measurements to monitor the deposition and etching 2D-TMDs layers. Next, the deposited and etched 2D-TMDs thin films were analyzed by spectroscopic ellipsometry to determine the thickness and refractive index, and the composition was determined by X-ray photoelectron spectroscopy (XPS). These ex-situ measurements confirmed the 2D-TMDs deposition and etching behavior findings from our in-situ studies.
(Invited) High-Performance Si Optical Modulator and Ge Photodetector and Their Application to Silicon Photonics Integrated Circuit
Authors: Fujikata Junichi , Takahashi Shigeki , Mogami Tohru , Kurata Kazuhiko , Takenaka Mitsuru , Nakamura Takahiro
Published: February 2020

We designed the optimum Si optical modulator (Si-MOD) structure with applying p-type-doped strained SiGe. By applying the strained Si70Ge30 layer, about twice larger optical modulation efficiency in VπL can be obtained in the simulation. In case of a relaxed Si70Ge30 layer, enhancement factor in VπL decrease to about 50%, but optical loss is comparable to that without a SiGe layer. We demonstrated a high modulation efficiency of 0.67 Vcm, which is about 50% more efficient than that of Si-MODs with just a lateral pn junction. From the Raman spectra and SIMS analyses, Ge composition of SiGe was estimated to be around 35%. Crystalline strain of SiGe was estimated to be 1.7% on the 0.04 mm2 square pattern, which is comparable to the theoretical value. On the other hand, it was estimated to be 1.1% for the selective growth of SiGe on the Si WG with a lateral pn junction. Therefore, biaxial strain of SiGe was a little relaxed, because the selective growth of SiGe pattern has a large aspect ratio with 400 nm width and 800 μm length. The Si-MOD showed 27.3 GHz bandwidth at -3 Vdc with 200μm-long phase-shifter. We demonstrated eye diagrams of NRZ (non-return-to-zero) 40 Gbps of 231-1 PRBS (pseudorandom binary sequence) and PAM (pulse amplitude modulation)-4 40Gbps at 1.3 μm wavelength under the condition of differential RF drive with 1.6-2.0 Vpp at -2Vdc. The optical loss of the Si-MOD is estimated to be 1.0-1.5 dB/mm, which is comparable to that of simulation. With increase in temperature up to 80℃, optical loss increased by about 0.3-0.5 dB, which would originate from band-gap shrinkage of a strained-SiGe layer. We obtained the clear eye diagram at 25 Gbps with 27-1 PRBS from the optical transceiver chip when the CMOS-driver output voltage was 0.9 Vpp and Vdc was -0.3V. ER (extinction ratio) of about 2 dB was obtained in case of 800μm-long phase shifter with 4-divided electrodes.

We also studied a high-speed and high-efficiency of surface-illumination type Ge photodetector (Ge-PD) with a 1800 nm thick Ge layer. By optimizing the anti-reflection coating stack structure, high responsivity of 0.8-0.9 A/W was uniformly obtained within the wafer. At 3 Vdc, about 15 GHz bandwidth was obtained. In case of the Ge-PD with thick Ge-layer, photo-carrier transit time mainly limits the frequency bandwidth. Therefore, we optimized the layered structure of Ge thickness on SOI to satisfy the high-responsivity and high-bandwidth. We demonstrated an output waveform from integrated CMOS-TIA (trans-impedance amplifier) at 25 Gbps with 27-1 PRBS at 1.3 μm wavelength at 3.3 Vdc. Clear eye opening was obtained, which would contribute to the efficient optical interconnect.
(Invited) Orientation Dependence of the Hole Ballistic Velocity in Si, Sige, and Ge Thin-Body Structures with Uniaxial Compressive Strain
Authors: Teherani James T.
Published: February 2020

Uniaxial compressive strain of p-MOSFETs has significantly improved p-MOS performance since it was introduced into high-volume manufacturing in Intel's 90-nm node. Further increases in compressive strain and the Ge fraction of the Si1-xGex channel at successive technology nodes have led to increased hole mobility (and, therefore, increased hole ballistic velocity) in p-MOSFETs over time. While the hole mobility improvement for uniaxial compressive strain along a [110] channel (with a (001) wafer surface) is widely known, the orientation dependence of uniaxial strain on the hole ballistic for arbitrary channel and surface directions has received less attention. In this talk, we use quantum-mechanical strain-dependent 6×6 k·p band-structure simulations to provide a comprehensive theoretical analysis of the impact of crystallographic orientation of the uniaxial strain, channel, and surface direction on the average hole ballistic velocity in thin-body structures of Si, SiGe, and Ge.
The Growth of GeSn Layer on Patterned Si Substrate by MBE Method
Authors: Li Chuanbo , Feng Shuai , Chen Xiao , Wang Yiquan , Cheng Buwen
Published: February 2020

GeSn is an important Si based semiconductor material due to its direct band characteristic. The small amount of Sn into GeSn alloy will induce a high-efficiency optical detection in the full-band communication at low concentration of Sn (approximately 3%). It has attracted lots of attention in recent years. However, due to the low solid solubility of Sn in Ge and large lattice mismatch, the growth of GeSn on Si is still a challenge. High-quality GeSn alloy have been grown by molecular beam epitaxy (MBE) and chemical vapor deposition (CVD), but there is still high the dislocation density. We have reported a new way to grow the defect-free GeSn alloy strips on Si substrates with the assistance of Sn. The lateral growth of GeSn alloy strips were grown on Si(111) by Sn self-catalyzed method. The GeSn materials are grown in a custom-designed MBE system with a base pressure of 5 × 10−8 Pa. The Here the growth of GeSn strips are studied on pattered substrate. We will discuss the growth mechanism and the impact factors on the materials. It is found that Sn has an important impact on morphology of the GeSn materials and different depositions and annealing times of Sn will impact the morphology of the materials. GeSn alloy strips show a good quality by the TEM micrographs and the SAED patterns(Fig.1). No dislocation is found in the grown material. GeSn growth on patterned substrate is also discussed.
(Invited) Organic Thermoelectric Materials and Devices Enabling New Thermal Management and Conversion Technologies
Authors: Yee Shannon K.
Published: February 2020

Within the last 3 years, thermoelectric technologies have seen renewed global deployment providing unique solutions to pressing thermal problems. Today thermoelectric technologies are helping to ensure vaccines viably reach the most remote locations in the world, are providing personal comfort in wearable devices addressing medical circulatory conditions, and are being designed for integration into electric vehicles thereby reducing the global warming contributions of refrigerants in conventional air conditioning systems. The majority of these technologies have resulted from innovative engineers utilizing conventional materials in niche applications. However, additional societal contributions can be achieved by leveraging the large-area processability and abundance of polymer-based thermoelectrics.

Unfortunately, the material performance of polymer-based thermoelectric materials is lacking compared to their inorganic counterparts. To circumvent this challenge, composites or hybrid organic-inorganic materials are often employed in functional devices. Furthermore, while there is an abundance of p-type materials to select from, there are few air-stable n-type thermoelectric materials. Metal coordinated polymers (or metallo-organic polymers) are one promising class of thermoelectric materials where a metal (or semimetal) atom is present along the polymer backbone. This structure produces periodic centers of high electron density, which, when coupled to the vibrational modes (e.g., vibrons or phonons), could result in appreciable power factors. Both air-stable p-type and n-type metal coordinated polymers can be readily synthesized from abundant materials and are promising scalable alternatives to inorganics that leverage solution processing.

This invited talk will first provide a motivating overview of emerging thermoelectric technologies being developed through the Scalable Thermal Energy Engineering Laboratory (STEEL) directed by Prof. Shannon Yee at the Georgia Institute of Technology. Next, this talk will discuss progress in synthesizing and controlling the thermoelectric properties of poly(nickel-ethenetetrathiolate) (i.e., Ni-ETT) and poly(nickel-tetrathiooxalate) (i.e., Ni-TTO), which are both air-stable n-type thermoelectric materials containing nickel along the polymer backbone. Next, this talk will discuss recent on-going work studying p-type chalcogenophene polymers, where the isovalent series of polythiophene through polytellurophene will be discussed. Finally, this talk will introduce new thermoelectric device architectures, specifically printable, that are enabled by these materials. Throughout this talk emphasis will be placed on the engineering and scaling challenges, which have been overlooked in the pursuit of high performance materials, but are most critical to realizing thermoelectric devices.
(Invited) Extendibility of Copper Metallization and Alternative Conductors in 7nm Node and Beyond
Authors: Nogami Takeshi
Published: February 2020

Copper metallization faces to trade-off between manufacturability / reliability and performance (Line resistance, capacitance, via resistance) in logic LSI in the 7 nm node and beyond. Industry started to explore alternative conductors which have intrinsic material features to lead to superior electromigration reliability to copper and come to have competitive resistance performance in fine dimension where the surface scattering of electrons dominates the resistivity of interconnects. In this talk, an advanced copper interconnect technology – through-cobalt self-forming barrier (tCoSFB) and through-ruthenium self-forming barrier (tRuSFB) which maximize copper volume by thinning down of the diffusion barrier without losing reliability is introduced. Manganese based diffusion barrier is formed with Mn atoms which diffused through the Co or Ru wetting layer. Integrity of the tCoSFB / tRuSFB copper interconnect is discussed and compared to other copper metallization schemes and alternative conductors. It is concluded that tCoSFB / tRuSFB has a potential to extend the use of copper interconnect to 7 nm node and beyond.
Multifunctional Materials for Emerging Technologies
Authors: Rosei Federico
Published: February 2020

As the age of fossil fuels is coming to an end, now more than ever there is the need for more efficient and sustainable renewable energy technologies. This presentation will give an overview on recent developments in solar technologies that may address, in part the energy challenge. In particular, nanostructured materials synthesized via plasma based approaches present an opportunity for future generation low cost manufacturing of devices [1]. We demonstrate various multifunctional materials, namely materials that exhibit more than one functionality, and structure/property relationships in such systems, including new strategies for the synthesis of multifunctional nanoscale materials to be used for applications in electronics and photovoltaics [2-31].

References

[1] F. Rosei, J. Phys. Cond. Matt.
16, S1373 (2004); [2] C. Yan et al., Adv.
Mater.
22, 1741 (2010); [3] C. Yan et al., J. Am.
Chem. Soc.
132, 8868 (2010); [4] R. Nechache et al., Adv. Mater.
23, 1724 (2011); [5] R. Nechache et al., Appl.
Phys.
Lett.
98, 202902 (2011); [6] G. Chen et al., Chem. Comm.
48, 8009 (2012); [7] G. Chen et al., Adv.
Func. Mater.
22, 3914 (2012); [8] R. Nechache et al., Nanoscale
4, 5588 (2012); [9] J. Toster et al., Nanoscale
5, 873 (2013); [10] T. Dembele et al., J. Power Sources
233, 93 (2013); [11] S. Li et al., Chem. Comm.
49, 5856 (2013); [12] T. Dembele et al., J. Phys. Chem. C
117, 14510 (2013); [13] R. Nechache et al., Nature Photonics
9, 61 (2015); [14] R. Nechache et al., Nanoscale
8, 3237 (2016); [15] R. Adhikari et al. Nano Energy
27, 265 (2016); [16] H. Zhao et al., Small
12, 3888 (2016); [17] J. Chakrabartty et al., Nanotechnology
27, 215402 (2016); [18] D. Benetti et al., J. Mater. Chem. C
4, 3555 (2016); [19] K. Basu et al., Sci. Rep.
6, 23312 (2016); [20] Y. Zhou et al., Adv. En. Mater.
6, 1501913 (2016); [21] H. Zhao et al., Nanoscale
8, 4217 (2016); [22] L. Jin et al., Adv. Sci.
3, 1500345 (2016); [23] H. Zhao et al., Small
11, 5741 (2015); [24] S. Li et al., Small
11, 4018 (2015); [25] K.T. Dembele et al., J. Mater.
Chem. A
3, 2580 (2015); [26] H. Zhao et al., Nano Energy
34, 214–223 (2017); [27] S. Li et al., Nano Energy
35, 92–100 (2017); [28] G.S. Selopal et al., Adv. Func. Mater.
27, 1401468 (2017); [29] X. Tong et al., Adv. En. Mater.
8, 1701432 (2018); [30] H. Zhao, F. Rosei, Chem
3, 229–258 (2017); [31] J. Chakrabartty et al., Nature Phot., in press (2018).