bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Metallic Nanocoatings on Optical Fibers as a Sensor Platform
Authors: Mandia David J. , Zhou Wenjun , Wells Adam , Albert Jacques , Barry Sean Thomas 
Published: February 2020

Optical fibres are excellent platforms on which to build a sensor: they substrate is inexpensive, and produced in tonnes per year. The technology effectively couples light and materials, and employs inexpensive (telecommunication) tools to interrogate the results. We are working on a tilted fibre Bragg grating (TFBG) sensor using atomic layer deposition (ALD) to modify the surface interface (Figure 1).
By printing a FBG into the core of an optical fibre, light “modes" that were confined to the core can be directed to the cladding interface. These light modes can then sense changes in this interface, and these changes can be read if the light is directed back into the core. Depositing nanoparticulate films onto the cladding surface alters the effect on these cladding modes. They undergo a wavelength shift and a "peak-to-peak" amplitude change that is significantly different than is seen in uncoated fibres. We have been exploring the deposition of copper, silver, and gold metal films on optical fibre surfaces and investigating the changes in the light modes.
The changes in the light modes that interact at the fibre metal interface are sensitive to the surrounding index of refraction. So, by using a high-permittivity dielectric material between the fibre and the metal coating, the sensitivity can be changed.
Thus, the sensor platform that will be discussed consists of an optical fibre coated in a high-K dielectric material, and then further decorated with metal nanoparticles. The dielectric material is typically deposited by ALD, and the metal is typically deposited by either chemical vapour deposition or atomic layer deposition.
This presentation will cover an overview of the chemistry of the precursor compounds for thin film deposition, the film deposition processes, and an interpretation of the resulting sensing ability of the cladding light modes. The wavelength shift is stronger when the device experiences a higher surrounding refractive index (SRI). This happens at low thicknesses, and can be exploited as an SRI detector. Interestingly, there is a significant difference in the spectra for a monolayer of discrete nanoparticles compared to a connected metallic film, also making these devices useful for detecting conductive film deposition.

Figure 1
Evaluation of InGaAs and InP Compatibility with Alkaline Photoresist Stripping Formulations
Authors: Westwood Glenn 
Published: February 2020

III-V semiconductors, such as InGaAs, are leading contenders to replace Si as high-mobility channel materials for sub-10 nm finFETs.(1,2) Implementation of these high-mobility materials into FEOL processes faces many challenges because of the chemical sensitivity and complex nature of these materials relative to the conventional Si channel. In particular, damage from wet cleaning solutions is a major concern that needs to be understood and controlled when designing new cleaning formulations for use in the manufacture of III-V based devices. Herein, we will describe our work at understanding InGaAs and InP compatibility with formulated alkaline photoresist strippers with a focus on the impact of solvent and alkaline component selection.
Initial studies focused on etch rates of InGaAs and InP in a series of proprietary cleaning chemistries. InGaAs films (500 Å) on InP – as well as bulk InP – wafers were used for this study. Etch rates were determined by energy-dispersive X-ray spectroscopy (EDX) as well as by gallium and arsenic leaching via ICP-MS. While acidic chemistries in general showed excellent compatibility, alkaline- and amine-based chemistries displayed varying levels of compatibility with InGaAs.
Because of the range of compatibilities observed in alkaline chemistries, we explored the impact of solvent and alkali selection as well as water content on selectivity. Specifically, we evaluated a series of non-proprietary solutions using a selection of solvent types, alkaline components, and water content (semi-aqueous vs. non-aqueous). The impacts of these components will be discussed and compared to results previously presented for GaAs etched in these same chemistries.(3)
For the strippers that are reported to be highly compatible with InGaAs and InP, a more thorough analysis of surface changes will be reported including changes in roughness (AFM) and composition (XPS). The results and key learnings from this study will be discussed in relation to how InGaAs and InP may be cleaned with limited surface damage.
1) International Technology Roadmap for Semiconductors, see www.itrs.net
2) J. A. del Alomo, Nature, 479, 317 (2011).
3) G. Westwood, SEMATECH Surface Preparation and Cleaning Conference, Austin, TX, 2012.
(Invited) Scavenging Kinetics of Interfacial SiO2 in HfO2/SiO2/Si Gate Stacks
Authors: Toriumi Akira , Li Xiuyan 
Published: February 2020

SiO2-interface layer (IL) “scavenging” in high-k gate stacks needs to be understood for the interface control as well as for further EOT scaling. A simple model that the oxygen vacancy (Vo) was involved in the scavenging was proposed, but further details have not been elucidated well.
We have studied the SiO2-IL scavenging in HfO2/SiO2/Si gate stacks in UHV condition in place of metal electrode scavenging. This method has enabled us to study the diffusion and reaction in this system from the top surface without a metal gate.
In this talk, we particularly focus on the following three steps in the scavenging process.
(1) VO diffusion kinetics in scavenging
This has been studied by controlling as-deposited HfO2 stoichiometry by changing the deposition conditions.
(2) Substrate effect on scavenging
Various types of substrates with a same gate stack have been used for the scavenging experiment.
(3) Si diffusion kinetics in scavenging
Si out-diffusion from HfO2/SiO2/Si gate stacks has been investigated through the mass spectroscopy.
We present experimental results in each step. In particular, we notice that SiO2/Si interaction may be involved in this process, as well as that the scavenging causes SiO2-IL reduction. Furthermore, we propose an analytical model for the SiO2-IL scavenging. Interestingly, it looks like the Deal-Grove model for Si oxidation, but coefficients are related to each other in the scavenging.
These results are important not only for scavenging SiO2-IL in HfO2/SiO2/Si stacks but also for establishing the oxide electronics, because understanding of both cation and anion kinetics in oxides is critical to control the hetero-interface characteristics.
Investigation of Conversion Positive Electrode Active Materials for the Aluminum Rechargeable Battery
Authors: Chiku Masanobu , Kunisawa Takeshi , Higuchi Eiji , Inoue Hiroshi 
Published: February 2020

Introduction

As a post lithium ion battery, new rechargeable batteries with metal negative electrodes which form multivalent cations during discharging are actively being investigated because they are expected to have high specific power, high energy density and low cost. Mg is the most popular materials for the multivalent cation battery because it shows higher energy density (3837 mAh cm-3) than Li (2062 mAh cm-3). Al is two times as large in energy density (8043 mAh cm-3) as Mg. Thus Al rechargeable battery is a promising next generation power source.
To construct the Al rechargeable battery, investigation of the positive electrode material is necessary. Preciously, we reported the Al rechargeable battery using V­­2O5 positive electrode and its specific capacity was about 200 mAh g-1, however this battery can only be charged/discharged with 1/10 ~ 1/40 C rate and it is too low charging/discharging rate for practical application.1)
In this study, we have developed the Al rechargeable battery using CuF2 as the positive electrode to increase the high rate dischargeability. This battery can be operated with high charging/discharging rate, however, XRD data suggested that in the process of conversion reaction, CuCl and CuCl2 was produced by substitution of F- with Cl-supplied from the electrolyte. So, we also investigated transition chlorides (CuCl, CuCl2 CoCl2, FeCl2) as the conversion positive electrode active material for the Al rechargeable battery to increase specific power and energy density.

Experimental

All electrochemical measurements were performed with a glass cell. The electrolyte was a mixture of aluminum chloride, dipropylsulfone and toluene with the mole ratio of 1:10:5. An Al plate with diameter of 14 mm was used as counter and reference electrodes for all experiments. A glass fiber filter was used as separator.
44 mg of transition Chlorides and 5 mg of Ketjen black powders were mixed, and 1-Methyl-2-pyrrolidone and 4 mg of polyimide were added to the mixture to prepare a paste. The positive electrode was prepared by casting the paste onto a molybdenum current collector and drying at 230 °C.

Results and discussions

Figure 1 shows CVs of CuF2, CuCl and CuCl2 positive electrodes. Almost the same oxidation and reduction peaks were observed. This suggests that CuF2 was converted to CuCl or CuCl2 by substitution of F- with Cl-during charge-discharge reactions.
An Al rechargeable battery using CuCl and CuCl2 as cathode material was fabricated and subjected to charge-discharge tests (Figure. 2). For the initial 15 cycles, discharge capacity was higher than 150 mAh g-1, suggesting CuCl and CuCl2 was a new positive electrode material for Al rechargeable battery.
CoCl2 and FeCl2 positive electrodes showed oxidation and reduction peaks. However, their capacities were less than that of CuCl and CuCl2.

Reference

1) M. Chiku et al. 224thECS Meeting # 521

Figure 1
High Performance P2-Type Na2/3(Mn1/2Fe1/4Co1/4)O2 Cathode Material with Superior Rate Capability for Na-Ion Batteries
Authors: Liu Lei , Li Xin , Bo Shou-Hang , Wang Yan , Chen Hailong , Twu Nancy , Wu Di , Ceder Gerbrand 
Published: February 2020

We designed a new P2 type cathode material, P2-Na2/3(Mn1/2Fe1/4Co1/4)O2, by mixing transition metals in the TM layer in P2 type layered oxide to prevent the long range ordering of Na or transition metals and create a large single phase region which is conductive to good Na+ transport. Futhermore, we suppressed the undesirable monoclinic transition commonly observed in Mn-containing layered oxides by introducing the Co2+/3+ redox couple. As a result, P2-Na2/3(Mn1/2Fe1/4Co1/4)O2 shows so far the largest single phase region and the highest rate performance among layered oxide cathode materials. We believe this work has opened the door for the application of sodium ion batteries in high power energy storage devices.
New Carbon Materials with Large Closed Pore Volume As Anode for High Energy Na-Ion Batteries
Authors: Kano Akira , Hojo Nobuhiko , Ito Shuji , Fujimoto Masahisa , Nakura Kensuke 
Published: February 2020

Recently demand for Li-ion batteries is growing as power sources for various applications such as electric vehicles and electric energy storage systems, because their high energy density and light weight properties are suitable for these applications. However, lithium resources may be insufficient to meet the increasing demand for these applications. Na-ion batteries could be a promising alternative to Li-ion batteries thanks to the natural abundance and lower cost of sodium. Non-graphitized carbon materials such as hard carbon are well-studied as high capacity anode materials for Na-ion batteries. The discharge capacity of 200 - 300 mAh/g, which is lower than conventional graphite anode materials for Li-ion batteries, has been reported [1,2]. In addition, the insertion mechanism of Na-ion into non-graphitized carbon materials is proposed that Na-ions are first inserted between stacked graphene layers in the voltage range from 2.0 V to 0.2 V (vs. Na metal), and then inserted into nano-pores in the voltage range from 0.2 V to 0.0 V (vs. Na metal) [2]. In this study, we focused on the pore structure of carbon materials and investigated the relationship between the carbon structures and electrochemical properties to clarify the optimum pore structure and propose a new carbon material as anode for high energy Na-ion batteries.
Non-graphitized carbon samples were synthesized by heating various raw materials at between 1000 and 2600 °C under flowing argon. The pore structure of the synthesized carbon samples was characterized by using argon and nitrogen adsorption measurement and helium gas densitometry. Electrochemical properties were evaluated by using laminate-type cell with Na metals as the counter electrode and the reference electrode.
Open and closed pore volumes of the synthesized carbons were calculated and the relationship between the reversible capacity and pore volume was investigated. As seen in Figure 1, an almost linear relationship between the reversible capacity in the voltage range from 0.2 to 0.0 V (vs. Na metal) and the closed pore volume was confirmed. Some carbon materials with large closed pore volume on the basis of this relationship were designed and successfully synthesized. Figure 2 shows charge/discharge curves of one of synthesized carbon samples. This carbon sample had the closed pore volume of 0.37 cc/g and its discharge capacity reached 413 mAh/g. This result suggests that Na-ion could be inserted reversibly in the closed pore and non-graphitized carbons with large closed pore volume may be promising for high capacity anode materials for Na-ion batteries.
[1] D. A. Stevens et al, J. Electrochem. Soc., 148 (2001) A803
[2] S.Komaba et al, ACS Appl. Mater. Interfaces, 3 (2011) 4165

Figure 1
Morphology Progression of Electrodeposited Li2O2 during Charging of Li/O2 Batteries
Authors: Griffith Lucas Daniel , Sleightholme Alice , Siegel Donald J , Monroe Charles W 
Published: February 2020

Non-aqueous Li/O2 batteries could achieve much higher specific energies than lithium-ion (3-5x)1, making battery powered electric vehicles more competitive with traditional combustion vehicles.2 Realizing this promise however requires significant improvement in cycle life and cycling efficiency. Understanding the charge mechanism is crucial to lowering the charging overpotential, which in turn would increase efficiency. Observing the process of deposition and dissolution of electrodeposited Li2O2 in Li/O2 cells can shed light on the charging mechanism.
During charge, the amount of energy necessary to decompose Li2O2 likely depends on the morphology of the Li2O2 particles deposited3-5: higher surface energy morphologies should require less energy. The morphology formed on discharge depends heavily on cell potential with higher energy particles formed at higher overpotentials.4,5 Observing how Li2O2 is consumed during charge could further explain the relationship between cell overpotentials and Li2O2 morphology, as well as probe any differences in the discharge and charge mechanisms.
In this talk we will show how the morphology of electrochemically deposited Li2O2 changes at intermediate states of charge in a Li/O2 cell. Cells are discharged and charged at constant rate of 0.5 mAcm–2 as described in a previous report.5 After discharge is complete, various intermediate states of charge are sampled by stopping the charge at cell potentials of 3, 3.375, 3.75, 4.125, and 4.5 V. Partially cycled electrodes are harvested from the cell and imaged with scanning electron microscopy.
Figure 1 shows a typical discharge charge curve, with an image of a control electrode and the morphologies observed for a fully discharged cell and a cell charged to 4.5 V (coincidentally corresponding to about half of the discharge current). From this it is clear that Li2O2 is not consumed uniformly throughout the electrode during charge. The implications of the non-uniform consumption of Li2O2 for electron and O2 transport in the electrode during charge will be discussed.

Figure 1
Electrolyte Effects on Chemical Stability of NaO2 in Na-O2 Batteries
Authors: Ortiz-Vitoriano Nagore , Amanchukwu Chibueze V , Kwabi David , Hammond Paula T , Shao-Horn Yang 
Published: February 2020

Rechargeable metal-air (oxygen) batteries are receiving intense interest as possible alternatives to lithium-ion batteries, because of their potential to provide higher gravimetric energies. 1 While much attention has been focused on aprotic Li-O2 batteries, substantial challenges must be addressed before widespread commercialization is possible. Recently, a metal-air battery in which lithium has been replaced by sodium has received increasing attention.2 Although Na-O2 batteries present lower gravimetric energies on a cell basis (1605 or 1108 Wh/kg based on Na2O2 or NaO2 discharge products, respectively)2 than Li-O2 batteries (3505 Wh/kgLi2O2),1 much lower charge overpotentials (~100 mV) than those in typical Li-O2 batteries (~1000 mV) have been reported based on reversible sodium superoxide (NaO2) formation . Unlike Li-O2 batteries, for which Li2O2 is the only discharge product, NaO2, sodium peroxide (Na2O2) and sodium peroxide dihydrate (Na2O2 · 2H2O), or a mixture, have been identified in Na-O2 batteries in ether-based electrolytes using a range of carbon electrode types.
Here we show NaO2 as the only discharge product from Na-O2 cells with carbon nanotubes in 1,2-dimethoxyethane from X-ray diffraction and Raman spectroscopy. Immediately after discharge, no Na2O2 · 2H2O was found in the discharged electrode, even with H2O present in the electrolyte up to 6000 ppm. However, Na2O2 · 2H2O was detected upon ageing the electrode in the electrolyte, and the amount of Na2O2 · 2H2O was seen to increase with increasing rest time in the electrolyte. More importantly, the reversibility of the reaction is affected by the presence of Na2O2 · 2H2O, where the cells charged immediately after discharge show a reversible reaction , and the cells charged after resting the electrode in the electrolyte for several hours showed poor reversibility.
The rechargeable nature of a Na-O2 cell is governed by the formation and oxidation of NaO2, making it vital to study the stability of the electrolyte in the presence of NaO2, and also to prevent the formation of irreversible side products.

REFERENCES
1. D. G. Kwabi, N. Ortiz-Vitoriano, S. A. Freunberger, Y. Chen, N. Imanishi, P. G. Bruce, Y. Shao-Horn, MRS Bull.
39, 443 (2014).
2. P. Hartmann, C. L. Bender, M. Vračar, A. K. Dürr, A. Garsuch, J. Janek, P. Adelhelm, Nat. Mater.
12, 228 (2013).
Homogeneous and Stable Lithium Electrodeposition through a Thin Single-Ion Conducting Layer for High Cycling Stability of Lithium Metal Secondary Batteries
Authors: Song Jongchan , Lee Hongkyung , Park Jung-Ki , Kim Hee-Tak 
Published: February 2020

The inhomogneous and unstable Li electrodeposition of lithium metal electrode has been a major impedment to the realization of rechargeable lithium metal batteries. Although polymeric single ion conductors can provide more homogeneous Li electrodeposition owing to their high Li ion transference number, their poor ionic conductivities prevent practical battery design. In the paper, we sugest a hybrid electrolyte based on a few micron-thick single-ion conducting layer laminated on Li metal electrode and a liquid electrolyte, which allows rapid Li+ transport and stable Li electrodeposition. The introduction of the single-ion conducting layer increases Li+ transference number from 0.451 to 0.855, consequently suppressig the generation of Li dendrite as demonstrated by SEM and impedance analysis. Reducing the thickness of the single-ion conducting layer down to a few microns and incorporating the bi-ionic liquid electrolyte permit room-temperature operation at high current densities. The Li/Li symmetric cell with the hybrid approach operate at a high current density of 10 mA cm-2 for more than 2000 h, which corresponds to more than five-fold enhancement compared to bare Li metal electrode, and the protyopye Li/LiCoO2 battery offers cycling stability more than 350 cycles at 0.2 C, demonstraing the practical applicability of this approach.
Electrolyte Solutions for Magnesium Rechageable Batteries
Authors: Abe Takeshi , Inoo Akane , Miyazaki Kohei , Fukutsuka Tomokazu 
Published: February 2020

Innovative rechargeable batteries beyond the present lithium-ion batteries (LIB) have been investigated for the environmental and energy problem. Among the batteries, rechargeable magnesium metal batteries have attracted much attention, since magnesium metal as negative electrode can bring high volumetric energy density owing to the two-electron reaction, low electrode potential, and lightness. Until now, the electrolyte solutions used for rechargeable magnesium metal batteries are tetrahydrofuran (THF) or 1,2-dimethoxyethane (DME) based electrolyte solutions. The boiling points of THF and DME are 66°C and 85°C, respectively. In order to eliminate the water in the rechargeable magnesium metal battery system, at least 100°C is required for the working temperature. However, THF or DME based electrolyte solutions do not meet the criteria. Therefore, we focused on the triethylene glycol dimethyl ether (triglyme) as a solvent since the boiling point of triglyme is 216°C. As a magnesium salt, magnesium(II) bis(trifluoromethane sulfonyl) amide (Mg(TFSA)2) was selected since TFSA- is a large anion and Mg(TFSA)2 is expected to be highly dissociative in triglyme. By using this system, we can increase the working temperature more than 100°C for rechargeable magnesium metal battery system[1]. As a proof-of-concept, Orikasa et al. reported that a rechargeable magnesium metal battery composed of insertion-type MgFeSiO4 positive electrode can work at 100°C in triglyme-based electrolyte solution [2]. This result indicated that we can fabricate high safety rechargeable magnesium metal batteries at ambient temperature by selecting appropriate positive electrodes. Then, the electrochemical behavior of electrolyte solution at ambient temperature is also important. In this conference, we reports the reversible magnesium metal deposition and dissolution in the Mg(TFSA)2/glymes solution at ambient temperature. In addition, we report new magnesium salt in triglyme.
[1] T. Fukutsuka, K. Asaka, A. Inoo, R. Yasui, K. Miyazaki, T. Abe, K. Nishio, and Y. Uchimoto, Chemistry Letters, 11, 1788-1790 (2014).
[2] Y. Orikasa, T. Masese, Y. Koyama, T. Mori, M. Hattori, K. Yamamoto, T. Okado, Z. D. Huang, T. Minato, C. Tassel, J. Kim, Y. Kobayashi, T. Abe, H. Kageyama, and Y. Uchimoto, Sci. Rep. 2014, doi: 10.1038/srep05622.
The Mg-V2O5 Intercalation Phase Diagram First Principles
Authors: Gautam Gopalakrishnan Sai , Canepa Pieremanuele , Abdellahi Aziz , Urban Alexander , Malik Rahul , Ceder Gerbrand 
Published: February 2020

Multi-valent (MV) ion intercalation batteries that replace the Li+ with a MV cation such as Mg2+, provide a realistic and compelling approach to meet the high energy density demanded by the next generation of electronics and vehicles. One of the challenges in achieving high energy density MV-ion systems is to develop a suitable cathode with a high enough voltage and diffusivity of the MV cation. Mg intercalation into V2O5 is one of the very few that has been shown to function reversibly at reasonable efficiency. In this study, we gain insight into the thermodynamics of Mg insertion into V2O5 from first-principles calculations. We have calculated the 0 K phase diagram, the equilibrium voltage curves and the migration barriers for Mg diffusion in both the α and δ-V2O5 polymorphs. Our calculations indicate that Mg in V2O5 is a “phase separating” system at room temperature and benchmarking our calculations with experiments leads to the conclusion that Mg cycles on a metastable α-V2O5 host. We believe that this study can be further used to improve the performance of V2O5 as a cathode material for Mg-batteries.