bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Engineered Electrode Materials Via Dry Processing
Authors: Obrovac Mark 
Published: July 2022

Dry bulk processing methods can offer surprising control of particle shape, size, internal composition, and surface morphology. Mechanofusion is a method that can be used to smooth, spheronize, coat, and embed particles [1–4]. Dry particle microgranulation (DPMG) is a newly developed mechanofusion method in which ~50 μm speres are added to the process as "templating" media [5]. Here it will be shown that DPMG and new applications of mechanofusion offer unprecedented control in particle shape, internal porosity, and internal composition variation, enabling the creation of never before possible highly engineered particles, including:

consolidating submicron particles into dense and uniform ~10 μm particles that are spherical or tetrahedral in shape

spontaneous formation of core/shell particles from a mixture of submicron particles with different compositions

creating spherical graphite particles from fine flake graphite

embedding nanoparticles within the core of ~10 μm host particles

applying fused dense oxide particle coatings

smoothing the surface of polycrystalline particles to lower their surface area

Such methods can produce no waste and operate at 100 % yields, greatly reducing environmental impact and cost compared to other commercial particle production methods. This offers tremendous opportunity for creating sustainable advanced battery materials. Examples of new cathode and anode materials synthesized by these methods and opportunities for new materials will be discussed.

References

[1] L. Zheng, T.D. Hatchard, M.N. Obrovac, A high-quality mechanofusion coating for enhancing lithium-ion battery cathode material performance, MRS Commun. 9 (2019) 245–250. doi:10.1557/mrc.2018.209.
[2] Y. Cao, T.D. Hatchard, R.A. Dunlap, M.N. Obrovac, Mechanofusion-derived Si-alloy/graphite composite electrode materials for Li-ion batteries, J. Mater. Chem. A. 7 (2019) 8335–8343. doi:10.1039/C9TA00132H.
[3] L. Zheng, C. Wei, M.D.L. Garayt, J. MacInnis, M.N. Obrovac, Spherically Smooth Cathode Particles by Mechanofusion Processing, J. Electrochem. Soc. 166 (2019) A2924–A2927. doi:10.1149/2.0681913jes.
[4] Y. Liu, M. Charlton, J. Wang, J.C. Bennett, M.N. Obrovac, Si 85 Fe 15 O x Alloy Anode Materials with High Thermal Stability for Lithium Ion Batteries, J. Electrochem. Soc. 168 (2021) 110521. doi:10.1149/1945-7111/ac3163.
[5] M.N. Obrovac, L. Zheng, M.D.L. Garayt, Engineered Particle Synthesis by Dry Particle Microgranulation, Cell Reports Phys. Sci. 1 (2020) 100063. doi:10.1016/j.xcrp.2020.100063.
Upscaling of the Laser Structuring of Lithium-Ion Battery Electrodes - Process Development and Electrochemical Properties As a Function of Design Patterns
Authors: Sterzl Yannic , Pfleging Wilhelm 
Published: July 2022

Structuring of electrodes for lithium-ion batteries by using ultrashort pulsed laser ablation is a quite promising approach to significantly increase the electrochemical performance of lithium-ion batteries. The main impact of such 3D electrodes is due to shortening of lithium-ion diffusion pathways and improving the electrolyte wetting of composite electrodes The latter is reducing the electrolyte filling process time and saving the need for warm aging in the manufacturing process. The 3D electrode concept, in combination with an increase in electrode layer thickness, facilitates an increase in energy and power density of batteries at the same time. To implement the laser structuring process in industrial cell manufacturing, an adaptation of the ultrafast laser technology to the coating speed has to be established.
In the presented study, the use of an ultrashort pulsed laser system of high power up to 300 W and high repetition rate in the MHz regime was evaluated regarding processing speed for patterning of graphite and silicon/graphite anodes. For composite graphite anodes (film thickness > 76 µm) with an areal capacity of about 2.5 – 4.0 mAh/cm2 and a thick-film silicon/graphite anode with 5 wt.% silicon content (film thickness 80 µm, areal capacity 4.3 mAh/cm2) the laser and process parameters and processing speed were evaluated and optimized. Furthermore, different structure patterns including hole, grid and line pattern, were studied regarding upscaling in roll-to-roll processing. The different types of patterns were evaluated with respect to accessible electrochemical properties. Prior to cell assembly and during post-mortem studies, the quality of structured electrodes was examined by profilometry and scanning electron microscopy. Debris formation and a thermal impact to active material and current collector could be avoided. To evaluate the electrochemical properties such as high rate capability, cell impedance, and cell lifetime, coin cells and pouch cells were manufactured. For this purpose, NMC 622 cathodes were prepared as the respective counter-electrodes and a cell balancing in the range of 1.1-1.2 was ensured.
Modelling Investigation of the Impact of Several Process Parameters on the Growth of the Viscous Layer during the Electropolishing
Authors: Boucher Aurelien , Fedi Baptiste , Doche Marie-Laure , Exbrayat Loic , Hihn Jean-Yves 
Published: July 2022

Electrochemical polishing (EP) is of great interest because it is able to deal with small parts exhibiting high complex shapes and/or material hard to be polished. Electropolishing is an electrolytic process based on the anodic dissolution of the workpiece under constant current or potential. Previous work done on stainless steel 316L shows the ability of the process to obtain smooth and bright surfaces [1]. The mechanisms describing EP are not yet fully understood, but several mechanisms can be taken into account for its description and prediction. Jacquet’s theory is based on the influence of an electric resistance gradient [2]. Elmore will then complete it with the gradient of concentration in metal cation [3,4]. Diard and al proposed the role of so called “acceptor” species [5]. While Hoar and Mowat’s work are based on the formation of an oxide layer on the surface [6]. All theories have in common the establishment of a viscous layer (solid or liquid) that governs the process. On this basis, it is possible to propose a numerical approach for the simulation of the viscous layer formation during electropolishing of stainless steel 316L and Inconel parts. The objective is to demonstrate the impact of various process parameters (electrochemical parameters, electrolyte nature and concentration as well as hydrodynamic conditions) on the growth and the stability of this layer.
The figure illustrate the simulation of the viscous layer growth during the electropolishing of a plate at the bottom taking into account the circulation of the electrolyte from the left to the right.
[1] C. Rotty, A. Mandroyan, M-L Doche, J-Y Hihn, Surface & Coatings Technology vol.307 p125–135 (2016).
[2] JACQUET, P.A., Electrolytic method for obtaining bright copper surfaces, Nature 135 (1935) 1076.
[3] ELMORE, W.C., Electrolytic Polishing, J. Appl. Phys. 10 (1939) 724–727, http://dx.doi.org/10.1063/1.1707257.
[4] ELMORE, W.C., Electrolytic Polishing II, J. Appl. Phys. 11 (1940) 797–799, http://dx.doi.org/10.1063/1.1712738.
[5] DIARD, J.P., LANDAUD, P., LE CANUT, J.-M., LE GORREC, B., Interprétation cinétique du palier de polissage électrochimique des métaux, 6ème forum sur les impédances électrochimiques, Montrouge, 1992.
[6] HOAR, T.P., MOWAT, J.A.S., Mechanism of electropolishing, Nature 165 (1950) 64–65.

Figure 1
Effect of N2-Anneal Temperature on Silicon Nitride Film: (I) Time-Dependent Dielectric Breakdown and ESR Evaluations
Authors: Kurita Hisatsugu , Nakamura Masataka , Miyagawa Hayato , Kamigaki Yoshiaki 
Published: July 2022

Silicon Nitride (SiN) film has been used as insulating material in many electronic devices such as capacitors and memories . In this report, the effect of N2 anneal temperature on charge break down (Qbd) of LP-CVD SiN film was electrically evaluated using the time-dependent dielectric breakdown (TDDB) test method, and the variation and the density of defects which exist in SiN film, in the oxide layer between SiN and Si substrate, and at the surface of Si substrate, were investigated using an Electron Spin Resonance (ESR) to reveal the defect behavior related to the trigger of Qbd.
SiN metal-insulator-metal (MIM) capacitors were fabricated to evaluate TDDB. A 54 nm dielectric layer of SiN film was deposited at 700 degree-C, using a mixture of dichlorosilane（SiH2Cl2）and ammonia (NH3) gasses, by a LP-CVD vertical furnace. For the lower and upper electrode, a 400 nm polycrystalline silicon films were deposited using a LP-CVD. In order to evaluate the effect of anneal temperature on SiN film breakdown frequency, these samples were annealed in nitrogen atmosphere at temperatures between 700 and 1150 degree-C for 1 hour, using a vertical furnace.
Breakdown voltage was measured with a current-voltage tester (HP4071A, Hewlett Packard) for each SiN MIM capacitor. The breakdown frequency was defined as the ratio of failed capacitors to tested capacitors. For the TDDB measurements, a constant current stress of 1.33 A/cm2 was applied to the MIM capacitors with the area of 0.00375cm2, 0.0075cm2, 0.015cm2 and 0.03cm2. For each area, 100 chips were made from one wafer and measured.
In Fig.1, SiN film breakdown frequency increases toward a peak at around the N2 anneal temperature of 900 degree-C, then decreases at 1000 degree-C, and at more than 1100 degree-C, the frequency increases again drastically at 1150 degree-C.
SiN films for ESR study were fabricated on Si wafer in the same LP-CVD process, and annealed in nitrogen atmosphere at temperatures between 700 and 1150 degree-C for 1 hour, using a vertical furnace.
The ESR measurements were performed at room temperature using an X-band spectrometer (JES-RE1X). To improve the signal-to-noise ratio of an ESR signal waveform, we set the accumulation number of magnetic-field (H) sweep about 300 times. Mn2+/ MgO hyperfine lines were used for the g marker, and spin densities were determined by using the standard of known spin content.
In Fig.2, Dangling bond density at silicon interface (Pb center) has a peak at 900 degree-C, and those in SiO2 (E’ center) and SiN film (K center) increase with increasing temperature from 1000 to 1150 degree-C. The former phenomena of Pb center coincides with the peak of SiN film breakdown frequency at 900 degree-C, and the latter one of E’ center and K center coincides with the tendency of increasing Qbd frequency at more than 1000 degree-C.

Figure 1
(Invited) 2D Dimensional Quantum Materials for CMOS and Beyond CMOS Devices
Authors: Jariwala Deep 
Published: July 2022

The isolation of a growing number of two-dimensional (2D) materials has inspired worldwide efforts to integrate distinct 2D materials into van der Waals (vdW) heterostructures. While a tremendous amount of research activity has occurred in assembling disparate 2D materials into “all-2D” van der Waals heterostructures and making outstanding progress on fundamental studies, practical applications of 2D materials will require a broader integration strategy. I will present our ongoing and recent work on integration of 2D materials with 3D electronic materials to realize logic switches and memory devices with novel functionality that can potentially augment the performance and functionality of Silicon technology. First, I will present our recent work on gate-tunable diode1 and tunnel junction devices2 based on integration of 2D chalcogenides with Si and GaN. Following this I will present our recent work on non-volatile memories based on Ferroelectric Field Effect Transistors (FE-FETs) made using a heterostructure of MoS2/AlScN3 and I also will present our work on Ferroelectric Diode (ferrodiode) devices4 also based on thin AlScN.
If time permits, I will also cover our ongoing efforts in scaling FE-FETs based on MoS2 and AlScN to < 100 nm channel lengths over large areas and also discuss in-memory computing using ferrodiode devices and also touch upon our efforts in photonics and light trapping using 2D semiconductors. I will end by giving a broad perspective on future opportunities of 2D semiconductors in micro and nanoelectronics.

References:

Miao, J.; Liu, X.; Jo, K.; He, K.; Saxena, R.; Song, B.; Zhang, H.; He, J.; Han, M.-G.; Hu, W.; Jariwala, D.
Nano Letters
2020, 20, (4), 2907-2915.

Miao, J.; Leblanc, C.; Liu, X.; Song, B.; Zhang, H.; Krylyuk, S.; Davydov, A. V.; Back, T.; Glavin, N. R.; Jariwala, D.,2D Metal Selenide-Silicon Steep Sub-Threshold Heterojunction Triodes with High On-Current Density arXiv:2111.06396

Liu, X.; Wang, D.; Zheng, J.; Musavigharavi, P.; Miao, J.; Stach, E. A.; Olsson III, R. H.; Jariwala, D.
Nano Letters
2021, 21, 3753–3761.

Liu, X.; Zheng, J.; Wang, D.; Musavigharavi, P.; Stach, E. A.; Olsson III, R.; Jariwala, D.
Applied Physics Letters
2021, 118, 202901
(Digital Presentation) CeOx Capping for Ferroelectric Y:HfO2 Films
Authors: Mizutani Kazuto , Hoshii Takuya , Wakabayashi Hitoshi , Tsutsui Kazuo , Kakushima Kuniyuki 
Published: July 2022

In recent years, HfO2 has been paid a lot of attention as a ferroelectric material due to its excellent scalability and complementary-metal-oxide-semiconductor (CMOS) process compatibility [1]. Some of the issues of ferroelectric HfO2 are wake-up and fatigue effect, increase and decrease of remanent polarization (P
r) along with switching cycles, and low endurance. Generally, these phenomena are understood as a result of the increase and redistribution of oxygen vacancies (VO) in HfO2 films [2]. By the way, it is reported that CeOx can release and absorb oxygen from adjacent oxides [3]. In this study, we propose the stacking structure of CeOx and ferroelectric HfO2 to improve endurance and investigate electric properties and voltage application sequence to suppress the fatigue effect.
5 mol% Y-doped HfO2 (Y:HfO2) and CeOx capping layers of metal-ferroelectric-metal (MFM) capacitors were deposited by atomic-layer-deposition (ALD) with W bottom and top electrodes by sputtering. Post metallization annealing (PMA) was performed at 450 and 500oC for the various duration. Figure 1 shows hysteresis loops of the capacitors with and without CeOx capping annealed at 450oC for 20 minutes. Large hysteresis on CeOx capping is observed even same annealing temperature and duration. Enhancement of transformation to ferroelectric phase can be explained as tensile stress to Y:HfO2 due to the difference of coefficient of thermal expansion (CTE) between CeOx and Y:HfO2. Variation of switching polarization (P
SW), the difference between positive and negative P
r, as a function of the number of switching cycles is also investigated and shown in figure 2. Both capacitors are annealed at 500oC for 100 minutes to crystallize. In the case of without CeOx capping, continuous wake-up effect and breakdown over 3×107 times switching are observed. On the other hand, the capacitor with CeOx capping shows a slight wake-up effect and fatigue after 106 times switching, additionally, endurance is improved to 3×109 times switching. The reason why fatigue and prolonging endurance occur is suspected that oxygen ions in the CeOx layer pin polarization domains and compensate VO in Y:HfO2. To suppress fatigue, we propose the recovery process by positive DC voltage application to top electrodes. In figure 3, hysteresis loops of the capacitor with CeOx capping before and after recovery voltage application. One can observe the larger hysteresis after recovery.
This work was supported by JST-COI (JPMJCE1309). One of the authors, Kazuto Mizutani, was supported by The FUTABA Foundation.
[1] T. S. Boscke, et al., Appl. Phys. Lett., 99, 102903 (2011). [2] M. Pesic, et al., Adv. Funct. Mater., 26, pp. 4601–4612 (2016). [3] M. Mamatrishat, et al., Vacuum, 86, pp. 1513-1513 (2012).

Figure 1
(Invited) Recent Progress on Molecular Beam Epitaxy of AlGaN Nanowires for Deep Ultraviolet Light Emitting Devices
Authors: Zhao Songrui , Zhang Qihua , Parimoo Heemal , Yin Xue 
Published: July 2022

Aluminum gallium nitride (AlGaN) ultrawide bandgap semiconductors have been attractive for their applications to disinfection, material identification, and ultraviolet (UV) curing, and for their potential to replace conventional mercury lamp based light sources. Remarkable progress has been made in the past decades from understanding material fundamentals to device performance improvement. Nonetheless, the enduring challenges related to high dislocation densities and poor p-type doping, among others, make AlGaN nanowires an alternative appealing platform. In this talk, I will discuss our recent development on the molecular beam epitaxy of AlGaN nanowires for deep UV light emitting devices.
First, I will show that by exploiting the compositional fluctuations in high Al content AlGaN nanowires in nitrogen-rich environment, electroluminescence (EL) at 207 nm can be obtained. Such EL emission is measured from the device top surface. As today it has remained challenging to obtain EL emission from the surface around this wavelength (i.e., near vacuum UV), such nanowires could offer an interesting approach to obtain surface emitting at near vacuum UV. I will further show that, by using graphene contact, the light output of surface emitting AlGaN nanowire deep UV LEDs can be improved. It is found that comparing to conventional metal contact, by using graphene contact the light output can be improved by a factor of two and the peak external quantum efficiency can be improved by a factor of four. Lastly, I will show that, by using nanowire template on Si substrate, AlN epilayers with a relatively smooth surface can be obtained, which further enables the formation of AlGaN epilayers with various Al contents on top. Such AlGaN epilayers are found to have high internal quantum efficiency, presumably due to a strong carrier localization effect. Current progress on device development using such an AlN on Si template will also be discussed.
The Microkinetic Performance Barriers of Ruthenium and Iridium Oxides during the Electrocatalytic Oxygen Evolution Reaction
Authors: Geppert Janis , Röse Philipp , Krewer Ulrike 
Published: July 2022

Electrocatalytic water splitting is currently one of the most promising reactions to produce green hydrogen in a de-fossilized energy system.[1] The performance of PEM electrolyzers is substantially determined by the sluggish reaction kinetics of the oxygen evolution reaction (OER). Even highly active catalysts such as nanoparticulated transition metal oxides IrO2, RuO2 and their mixtures IrxRu1-xO2 exhibit overpotentials up to several hundreds of millivolts.[2] Dynamic microkinetic modeling is a powerful tool to analyze the single reactions and their interplay during OER at the electrode surface.[3] Quantitative insight into process-limiting steps on different active sites on the material surface can be used to suggest ways to improve dynamic OER operation.
In this work, we present the analysis of an experimentally validated microkinetic model. It allows to study the electrocatalytic reaction mechanism including the coverage of emerging surface species (e.g. *OH, *O, *OOH and *OO) for a wide potential range including OER. We show that there is a correlation between performance and the Ir:Ru ratio, that can be explained by two different potential determining deprotonation steps. In particular, the highest equilibrium potentials of 1.44 V and 1.58 V are quantified for the production of the adsorbate species *OOH on rutile RuO2 and *OO on IrO2, respectively. During OER at a potential of >1.5 V, adsorbed oxygen *O covers >40 % of the active sites, suggesting that subsequent water adsorption is the major process limitation. The surface of the oxide mixtures IrxRu1-xO2, is found to consist of actives sites of both Ir and Ru on which the OER mechanism is processed independently and at different overpotentials. Compared to the pure oxides, the mixtures reveal reduced reaction energies of the potential determining deprotonation processes. One can conclude that incorporating Ru into IrO2 provides higher overall performance while stability is remained. Dynamic microkinetic modelling is therefore a viable method to study catalytic surface processes as well as their limitations and to make suggestions for improving the performance of electrocatalytic systems.
[1] K. Kalz et al., ChemCatChem, 2017, 9, 17.
[2] D. Escalera-López et al., ACS Catalysis, 2021, 11, 15, 9300.
[3] J. Geppert et al., Electrochimica Acta, 2021, 380, 137902.
3D Structured Au(NiMo)/Ti Catalysts for Hydrogen Evolution Reaction
Authors: Balciunaite Aldona , Barua Sukomol , Tamasiunaite Loreta , Vaičiūnienė Jūratė , Norkus Eugenijus 
Published: July 2022

Hydrogen generation via water splitting in alkaline media is the most promising, alternative, clean, and next-generation technology that can fulfill the future energy demands and overcome the challenge of global warming. The kinetics of hydrogen generation via water splitting through electrochemical process mainly rely on hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Material selection and material design are the keys to developing highly active, low-cost, and stable non-noble metal electrocatalysts but also are of great challenge.
The Au(NiMo)/Ti-based catalysts were prepared via chemical and electrochemical methods in this study. Initially, the NiMo coatings on the Ti surface (1x1cm) were electrodeposited from a bath containing 0.01 M Na2MoO4 and 0.01, 0.1, and 0.5 M NiSO4 in an acidic condition. The process of electrochemical deposition was carried out at the current of 0.1 mA and 1 mAfor 3 min. The gold nanoparticles were deposited on the previously prepared NiMo/Ti electrodes by galvanic displacement through their immersion into an acidic Au-containing solution for 10s. The morphology and composition of the newly prepared catalysts have been investigated via SEM, XRD, EDS, and ICP-OES. The investigation of electrocatalytic properties of the prepared catalysts was performed by recording linear sweep voltammograms in 1M NaOH solution at a potential scan rate of 10 mVs-1 at 25-75⁰C temperature range.
It was observed that the power densities for the newly prepared Au(NiMo)/Ti catalysts with the Au loading from 2 up to 4 µgAucm-2 were 1.3 to 1.8 times higher than using NiMo/Ti catalysts for HER.

Acknowledgment

This project has received funding from European Social Fund (project No 09.3.3-LMT-K-712-19-0138) under a grant agreement with the Research Council of Lithuania (LMTLT).