bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrodeposition of Metal Chalcogenides Nanostructures for Thermoelectrics
Authors: Kim Jiwon , Lee Chan Gi , Lim Jae-Hong , Myung Nosang Vincent
Published: December 2020

Metal Chalcogenide nanostructures have been extensively implemented for high-performance thermoelectric applications, which can directly convert waste-heat-energy into electricity, with the support of theoretical and empirical results. In fact, finding a novel and cost effective synthesis approach that facilitates the formation of stable and reproducible nanostructured thermoelectric materials determines the commercial applicability. The overall objective of this work is to synthesize metal chalcogenide nanostructures with outstanding thermoelectric performance by an electrodeposition technique, which is one of the most versatile methods for low dimensional nanostructures in a cost effective and scalable manner. Precise control over dimension, chemical composition, crystallinity, crystal structure, grain size, preferred orientation, and the attainment of nanoinclusions and/or intermediate phases based on thermodynamically favored solid-state phase transition yields optimal electrical transport and thermoelectric properties of the metal chalcogenide nanostructures. Herein, the electrodeposited nanostructures represented the enhancement of Seebeck coefficient without reducing the conductivity was investigated that was explained by a carrier energy filtering effect due to the band bending at the two-phase interfaces.
Electrochemical Deposition of Pd/Ag for Electrocatalytic Applications
Authors: Ispas Adriana , Bund Andreas
Published: December 2020

Palladium-based alloys play an important role in many industrial applications, e.g. for the production and conversion of hydrogen (1). Palladium based catalysts show high reactivity both for the oxygen reduction reaction (ORR) and alcohol oxidation reaction respectively. One of the major drawbacks related to the hydrogen permeability in Pd is the blistering of Pd films at high concentrations of hydrogen. One effective method against this problem is to stabilize the Pd by alloying it (2). In general, alloys are promising materials because many of their chemical and electronic properties can be varied in a systematic way by changing the composition (1,2).

Pd/Ag alloys can act as selective hydrogenation catalysts. Furthermore, they are also used in electrical contacts. The alloys with the composition Ag0.23Pd0.77 are important with regard to hydrogen diffusion and these alloys are employed industrially as a H2 purification membranes. Pd/Ag nanoparticles also show promising applications as a novel activator for electroless copper deposition.

This paper will present the electrodeposition of Pd/Ag layers from different electrolytes with different complexing agents onto brass, mild steel, gold and glassy carbon (GC) substrates, in order to determine the optimum conditions and the parameters for the deposition of alloys with a tailored composition. Cyclic voltammetry was carried out in sulfuric acid containing methanol to determine the electrocatalytic activities of the deposited Pd/Ag structures. Further characterizations were performed using SEM coupled with EDX and XRF, in order to investigate morphologies and compositions of the alloys. Shiny deposits with a globular morphology and good adhesion were obtained. The ratio of Pd/Ag ion concentration in different electrolytes proved to be very important for the quality of the deposits. The addition of NH4NO3 improved the ionic conductivity of the bath, but it also acted as a complexing agent for Pd2+ and Ag2+. Without its addition, the Ag/Pd deposits will tend to grow in the form of dendrites and sheet crystals.

The Pd/Ag deposits showed good electrocatalytic activity for the oxidation of methanol. That would render them promising candidates as anode materials in direct methanol fuel cells.

(1) Y. Xiao, B. Weng, G. Yu, J. Wang, B. Hu and Z. Chen, J. Appl. Electrochem. 36 (2006) 807-812.

(2) B. Sturzenegger and J. Cl. Puippe, Platinum Metals Rev. 28 (1984) 117-124.
Application of Various Iron-Based Plated Electrodes Under Different Plating Conditions As Air Electrodes for Metal-Air Batteries
Authors: Yoshihara Sachio , Sasaki Jiu
Published: December 2020

The purpose of this study was to investigate the difference in oxygen evolution and reduction reaction activity by changing the preparation conditions of Fe-Ni-W alloy plating. We produced Fe-Ni-W alloy plating that changed the concentration of Fe and W ions in the bath. It was described that the activity for oxygen evolution reaction (OER) depended on the containing W amount in the film, and also depended on the concentration of complex agent, Na3Cit･2H2O in the bath. When the concentration of Na3Cit･2H2O in the bath increased, the content of Fe-W in the film increased, and the Ni content decreased. It was found that the plated electrode with morphological large surface area showed good performance. In the case of oxygen reduction reaction (ORR), it was described that the activity depended on the contents of W in the film.
Bronze Electroplating: Stability, Nucleation and Growth Study of a New Green Formulation
Authors: Giurlani Walter , Fabbri Lorenzo , Vizza Martina , Marcantelli Patrick , Martinuzzi Stefano , Innocenti Massimo
Published: December 2020

Bronze electroplating is a widely used process in the electronics and costume jewelry industrial sectors as an anti-corrosion coating and barrier layer against intermetallic diffusion. The study of this alloy is also essential for the realization of copper-zinc-tin sulfide (CZTS) compounds, a quaternary semiconductor with a growing interest for the realization of thin film photovoltaic devices. The galvanic baths currently on the market are alkaline with a high amount of sodium or potassium cyanide to complex the metal ions. Cyanide salts are extremely dangerous for their toxicity, blocking cellular respiration. For this reason, cyanides are considered a danger both for the environment as well as for the workers with whom it comes in contact. In this study, a new eco-friendly, acidic and cyanide-free formulation was developed for the deposition of the Cu-Sn alloy.

To achieve this goal, methanesulfonic acid (MSA) was chosen as electrolyte, which is biodegradable as part of the natural sulfur cycle. Various recipes have been evaluated to obtain a solution that was stable over time and that did not lead to the precipitation or oxidation of its components. Copper sulphate, copper methanesulfonate and tin methanesulfonate solutions were used as precursors of the metals [1]. As stabilizing additives nitrilotriacetic acid (NTA) and 2-picolinic acid (2PA), complex agents for copper, and hydroquinone (HYD), antioxidant agent for tin, were evaluated. The composition of the films, obtained both by potentiostatic and galvanostatic deposition, were analyzed by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS) and, to investigate the structural phases of the deposits, XRD measurements were carried out. Finally, nucleation and growth as a function of the concentration of thiourea (TU) and potassium and sodium tartrate (PST), regulating additives for the deposition of copper and tin, respectively, were studied by chronoamperometric methods, in order to achieve progressive growth and therefore a lucid deposit. The present study funded by the PRIN Project (“Progetti di Ricerca di Rilevante Interesse Nazionale”), “Novel Multilayered and Micro-Machined Electrode Nano-Architectures for Electrocatalytic Applications (Fuel Cells and Electrolyzers)”, grant number 2017YH9MRK.

References:

[1] Fabbri, L. et al. Electrodeposition of White Bronzes on the Way to CZTS Absorber Films. J. Electrochem. Soc. 167, 022513 (2020). 10.1149/1945-7111/ab6c59.
Influence of Plating Conditions on Nickel-Chromium Alloy Electrodeposition
Authors: Ispas Adriana , Waibel Andreas , Fritz Mathias , Bund Andreas
Published: December 2020

Nickel-chromium alloys present high corrosion and high creep resistance. Due to the large difference between the standard potentials of the two metals, E0(Ni2+/Ni)=-230 mV and E0(Cr3+/Cr)=-760 mV, the alloy composition usually strongly depends on the current density chosen for deposition, on the nickel concentration in the electrolyte and the electrolyte temperature.

The electrodeposition of chromium from the trivalent oxidation state is more challenging compared to its hexavalent state. In aqueous solutions Cr(III) ions form complexes some of which have a very low ligand exchange rate. Thus, electrochemical deposition is difficult or only possible at a very slow deposition rate. In addition to the aquo complexes, complexes can also be formed with the anion of the corresponding metal salt. Normally, complexing agents, such as carboxylic acids, are added to the electrolyte in order to increase the deposition rate.

This paper will present recent results from authors’ lab on the electrodeposition of Ni-Cr alloys from aqueous electrolytes containing Cr(III) salts. The effect of formic and oxalic acids on the qualities of the deposits was investigated, as well as the influence of the deposition technique (direct or pulse plating), current density, nickel concentration in the electrolyte, temperature of the electrolyte, and the hydrodynamic conditions.

We could show that the chromium content in the deposits can be easily tuned via the composition and temperature of the electrolyte, and the current density. At high current densities and low nickel concentrations, chromium-rich layers with up to 64 wt-% chromium could be deposited. An increase in the temperature led to a significant decrease in the chromium content of the deposits. The layers grow compactly and show a globular structure. The deposited films changed from a crystalline to an amorphous structure with increasing chromium content.
Electroplating and Surface Analysis
Authors: Fabbri Lorenzo , Piciollo Emanuele , Fontanesi Claudio , Giurlani Walter , Mencherini Giulia , De Luca Antonio , Passaponti Maurizio , Innocenti Massimo
Published: December 2020

The interest in scientific research within the metal finishing sector is growing. The demand for durable metals and adaptable manufacturing processes are increasing across a wide range of applications, from aerospace and automotive to machinery and jewelry. An essential step in the production line is the surface engineering of metals, as this determines the final appearance and functionality of a product. Therein electroplating is recognized as a mature technology allowing the low cost fabrication of defined surfaces with extensive property profile. Galvanic electrodeposition accounts today for almost 40% of the global market value share with North America and Western Europe leading the scenery. Although technological and processing advancements occurred in the past forty years, industrial firms are still struggling to provide solutions to corrosion protection as well as reduction of toxic wastes. Specifically, large-scale industrialization of electroplating techniques will continue to be limited by strict environmental regulations. Due to adverse ecological impacts, the adoption of plating processes involving toxic metals such as lead or cadmium is prohibited. Moreover, price volatility of the highly demanding electroplated materials gold, copper and nickel is expected to impact the market share for more than 60% by 2026.

In that respect, alloy plating offers better answers in terms of economic growth and environmental sustainability due to fine tuning composition, morphology and crystallinity [1]. Here, current trends on alloy electrodeposition research are reviewed highlighting open challenges and process innovations from an industrial perspective. The main categories of alloy compounds are presented and the most important properties for the manufacturing process discussed. Particular attention is devoted to advances in industrial quality control and viable solutions for the reduction of precious metal content in electroplated accessories as well as replacement of cyanide and nickel baths with non-toxic compounds. The present study funded by the PRIN Project (“Progetti di Ricerca di Rilevante Interesse Nazionale”), “Novel Multilayered and Micro-Machined Electrode Nano-Architectures for Electrocatalytic Applications (Fuel Cells and Electrolyzers)”, grant number 2017YH9MRK.

References

[1] W. Giurlani, M. Innocenti et all. , Review, Coatings 2018, 8(8), 260.
Differentiating the Rate Capabilities of Lithium-Nickel-Manganese Oxide, Li[Ni1/2Mn3/2]O4, Insertion Materials and Electrodes Using Diluted Electrode Methods
Authors: Ariyoshi Kingo , Masuda Shumpei , Sugawa Jun
Published: December 2020

Development of high-power lithium-ion batteries requires the optimization of the electrode kinetics of lithium-insertion materials to improve the rate-capability of these devices. The rate-capability of a lithium-insertion electrodes is controlled by the concentration overvoltages arise from changes in the Li+ ion concentration at the electrode/electrolyte interface. Two distinct rate-capability behaviors prevail depending on whether charge transport is limited by Li-ion mass transfer within the solid particles or within the interstitial spaces of the electrode.

In this study, we used the diluted electrode method is employed to characterize the two types of the rate-capability behavior exhibited by the Li[Ni1/2Mn3/2]O4 (LiNiMO) electrodes. Porous electrode to a pseudo-single- particle electrode configurations are produced by diluting the LiNiMO content with Al2O3 spectator material while maintaining the weight, thickness, and porosity of the structure. Examination of diluted electrodes containing 5-88 wt% LiNiMO reveals the rate capability of low LiNiMO-content electrodes to be superior to that of high LiNiMO-content electrodes. The rate-determining step of low-content electrodes is the transport of Li+ ions through the solid phase, whereas the rate-determining step of high-content electrodes is Li+ ion transport through the liquid electrolyte phase.

This report is the first report to distinguish between the two kinds of rate-capability behavior in lithium-insertion materials and electrodes. By defining the range of rate-capability behavior, our results should guide future studies seeking to establish the electrode kinetics of lithium-insertion electrodes and to improve their capabilities through optimization of an electrode structure.

Figure 1
Chemically Derived K2Mn3O7 As a Potassium Insertion Material:Structure and Electrochemical Study
Authors: Sada Krishnakanth , Pralong Valerie , Barpanda Prabeer
Published: December 2020

Potassium-ion batteries (KIBs) are fast emerging as economic alternatives for partial replacement of Li-ion batteries in stationary large-scale storage application. With the rising concern over the price and availability of Li-based resources, Na-ion and K-ion batteries have come up to serve applications unrestricted by gravimetric/ volumetric energy density. When compared to Na-ion batteries, KIBs offer several merits including feasible K+ (de)insertion into graphite anode (244 mA h g-1), lower standard voltage (-2.93 V vs. SHE), high diffusion kinetics along with lower solvation radius [1].

To realize novel potassium insertion materials, we have proposed application of pristine and chemically modified (e.g. ion-exchange) sodium insertion compounds as cathodes in KIBs. Owing to the similar size of Na and K species, various sodium-based materials can act of host for K+ insertion. As a proof-of-concept study, NaxCoO2 and Na2Mn3O7 were successfully used as KIB cathodes with reversible capacity values of 82 and 132 mAh g-1 respectively [2-3]. Focusing on layered Na2Mn3O7, we have discovered a novel oxide phase by topotactic ion-exchange route using K2SO4 at room temperature. Assuming a layered structure, this new compound exhibits a reversible specific capacity of ~100 mA h g-1 at the current rate of C/20. It involves step-wise voltage profile with a nominal Mn4+/Mn3+ redox potential ~2.7 V (vs. K/K+) (Figure 1). Further, it exhibited robust cycling stability at different current rates, retaining a discharge capacity of 63 mA h g-1 even at 1C rate in the potential window of 1.5 to 3.8 V. The synthesis, structural features and electrochemical charge storage mechanism of this novel potassium insertion compound will be presented.

Reference
s
:

[1] H. Kim, J. C. Kim, M. Bianchini, D-H Seo, J. R Garcia, G. Ceder, Adv. Energy Mater. 8 (2017) 1702384.

[2] K. Sada, B. Senthilkumar, P. Barpanda, Chem. Commun. 61 (2017) 8588–8591.

[3] K. Sada, B. Senthilkumar, P. Barpanda, ACS Appl. Energy Mater. 10 (2018) 5410–5416.

Figure 1
(Invited) Manganese Dioxide Positive Electrodes for Aqueous Zinc-Ion Batteries
Authors: Adams Brian
Published: December 2020

Tremendous work has been made in a relatively short period of time on developing the rechargeable aqueous zinc-ion battery (ZIB). The ZIB using inexpensive/abundant raw active materials is a cheaper and safer alternative to Li-ion batteries (LIBs), particularly where portability is not of primary importance. The ZIB is also considered by many to be the most promising rechargeable zinc battery technology because it addresses many of the short-comings of traditional zinc battery chemistries. By using a near-neutral pH electrolyte as compared to a strong alkaline solution, cycling of the zinc metal electrode is improved drastically. The coulombic efficiency of zinc plating/stripping is increased and internal short circuits due to dendritic growth of zinc metal are suppressed. The slightly acidic (pH 4-6) electrolyte also allows for new reversible (de)intercalation mechanisms to occur at the positive electrode. This has led to the development of several novel classes of electrode materials which store zinc cations.

One such electrode material which is capable of intercalating Zn2+ cations is manganese dioxide. Compared to the alkaline Zn-MnO2 battery in which both the zinc negative electrode and the manganese dioxide positive electrodes undergo conversion reactions, the chemistry of the ZIB is simplified. Zn2+ is stripped from the negative electrode and intercalates into the positive electrode during discharge. Upon charge, Zn2+ cations de-intercalate from the positive electrode active material and plate back onto the negative electrode as zinc metal. In this work, various forms of manganese dioxide were explored in detail for use as the positive electrode active material for zinc intercalation. Different crystal structures of MnO2 were studied and several additional factors, such as particle size and morphology were found to impact the performance of Zn2+ intercalation. The diffusion coefficients were calculated and each material was cycled in a zinc-ion battery to determine its suitability as a Zn2+ intercalation electrode in a near-neutral aqueous system. Through this structure-properties correlation, general material design rules can be drawn, guiding future R&D efforts on ZIB chemistry.

Figure 1
Charge Storage Mechanism of a Quinone Polymer Electrode for Zinc-Ion Batteries
Authors: Zhang Ye , Liang Yanliang , Dong Hui , Wang Xiaojun , Yao Yan
Published: December 2020

Aqueous zinc-ion batteries (AZIBs) offer a potentially stable alternative to alkaline rechargeable zinc batteries in utilizing zinc metals for low-cost and safe energy storage. Two fundamental features of AZIBs are (1) near-neutral aqueous electrolytes, in which zinc dendrites growth is apparently suppressed compared with that in alkaline electrolytes, and (2) Zn2+ -storing cathode materials, which do not store protons in cathodes and maintain the near-neutral pH of an electrolyte throughout charge-discharge processes. Because of the importance of stored species at the cathode for the viability of a battery, the charge storage mechanism in cathode materials has been under scrutinization. Among cathode materials proposed for high-energy AZIBs, many vanadium oxides seem to store zinc-ions, while manganese oxides more often than not involve proton storage which raises concerns of pH variation of the electrolyte. Quinones have been recently proposed as versatile electrode materials for aqueous batteries. Early attempts of quinones for AZIBs have resulted in promising specific energy and cycling stability. It is therefore interesting to investigate the charge storage mechanism in these materials and assess their viability for practical applications.

This work focuses on the identification of stored ions in a quinone polymer, poly(benzoquinonyl sulfide) (PBQS), as an AZIB cathode material. Possible ions to be involved in the electrode reaction include zinc ions, protons, counter anions (in this case triflate), and their hydrated forms. Spectroscopic technologies suitable for qualitative and quantitative analyses of the electrode reaction of organic materials have undergone major development in recent years. Electrochemical quartz crystal microbalance (EQCM) is an established tool to quantitatively probe the stored ions in redox-active polymers and carbon materials. Recent advancement with dissipation monitoring (EQCM-D) further strengthened the technique for characterizing softer electrodes. On the other hand, Fourier transform infrared spectroscopy (FTIR) is a standard technique for qualitative detection of chemical groups, thus a useful tool to compliment EQCM-D which may lack chemical information. In-situ FTIR has been proven effective in monitoring the electrode reactions in organic carbonyl electrodes, though the use for detection of stored ions has not been reported. Here we combine EQCM-D and FTIR techniques for a comprehensive understanding of the charge storage mechanism of PBQS in a near-neutral zinc electrolyte.
Welcome Remarks - G01: Semiconductor Wafer Bonding: Science, Technology and Applications 16
Authors: Knechtel Roy
Published: December 2020

Welcome to G01: Semiconductor Wafer Bonding: Science, Technology and Applications 16! Take a moment to listen to welcome remarks from the lead organizer, Roy Knechtel.
(Invited) Materials for Solar Fuels: Coupling Efficient Water Splitting Catalysts and High-Performance Photovoltaics by Atomic Layer Deposition
Authors: McIntyre Paul C.
Published: December 2020

Atomic layer deposition (ALD), a cyclic form of chemical vapor deposition that occurs via a series of self-limiting chemisorption reactions, is an increasingly important enabler of nanotechnology and advanced energy technologies. Exciting energy-related applications of ALD that have emerged in recent years include surface passivation of photovoltaics, electrode coating for advanced batteries, and catalyst synthesis. In this presentation, I will summarize recent research in which ALD has been used to promote stable photoelectrolysis of water for solar fuel synthesis. ALD-grown TiO2 layers are found to be particularly effective in inhibiting oxidative corrosion of high-quality semiconductor absorbers and in electronically coupling these semiconductors to efficient catalysts for oxygen evolution, the kinetically-limiting step in water splitting. In addition, super-cycle ALD is used to alloy TiO2 with transition metal oxides that are themselves good catalysts for water oxidation and that exhibit a high work function. These layers produce high photovoltages in excess of 600 mV in n-Si Schottky MIS junction water splitting photoanodes. Such ALD-grown metal oxide alloys have the potential to become “all-in-one” catalyst/protection/hole-selective contact layers for photoelectrochemical devices. Finally, results obtained from a novel multijunction silicon photoelectrochemical cell incorporating ALD-TiO2 protection and exhibiting > 10% solar-to-hydrogen efficiency – with operation in electrolytes across a wide range of pH including pH 7 buffer solution - will be described.
Study of Novel Hafnium-Based Hybrid Thin Films By Molecular Layer Deposition
Authors: Hairisha Abulaiti , Bent Stacey F.
Published: December 2020

Molecular layer deposition (MLD) is a gas-phase reaction technique which relies on self-limiting surface reactions for growth of surface-bound polymers. Hybrid organic-inorganic materials usually possess properties distinct from both inorganic and organic components. MLD techniques can be used to deposit hybrid films with precisely defined composition and tunable properties that can be conformally deposited on high aspect ratio substrate. In this study, novel hybrid organic-inorganic hafnium based polymer films were successfully deposited using sequential exposures of a homoleptic tetrakis(dimethylamido)hafnium (TDMAH) complex and ethanolamine (EA) as the reactants by MLD. Hafnium nitrides and oxides have received much attention in the fields of microelectronics and lithium ion batteries, and thus are of interest as hybrid materials that may impart beneficial mechanical and chemical properties. To grow the Hf hybrid films, TDMAH and EA pulses were alternated with 120s of N2 purge. The processes were investigated as a function of temperature, precursor pulsing time and number of cycles. The results show that the self-limiting surface reactions possess a constant growth rate of ∼1.9 Å per cycle at 120 °C. Temperature-dependent growth characterization was performed for these hybrid materials. By increasing the temperature from 65 °C to 145 °C the growth rate decreases from ∼2.5 Å per cycle to ∼1.1 Å per cycle. The presence of expected C-N, C-O and -CH2 moieties in the MLD films were confirmed by Fourier transform infrared (FTIR) spectroscopy. Hafnium nitride and oxide bonds within hybrid thin films were identified by applying X-ray photoelectron spectroscopy (XPS). The results show that the deposited hafnium based organic-inorganic hybrid films contain both Hf – O and Hf – N bonds which enables flexibility, and thus have potential applications for both battery and microelectronics technologies.
(Invited) Layered Structure Cathodes; Prejudice, Inverse Concept and New Possibility
Authors: Kang Yongmook
Published: December 2020

Phase transformation of layered structure into spinel structure has been detrimental for most of layered oxide cathodes. Even if a lot of efforts have been made to relieve this highly irreversible phase transformation, there have been few successful results. However, we firstly observed the possibility to make this irreversible phase transformation extremely reversible by utilizing Na-birnessite (NaxMnO2•yH2O; Na-bir) or Li-birnessite (Li-bir) as basic structural units, which have distinctive layered structure containing crystal water. Herein, the crystal water in the structure contributes to generating metastable spinel-like phase, which is the key factor for making this unusual reversibility happen. The reversible structural rearrangement between layered and spinel-like phases during electrochemical reaction could activate new cation sites and enhance ion diffusion with higher structural stability. This unprecedented reversible phase transformation between spinel and layered structure was also observed for the Na-bir or Li-bir with some organic moelcules in place of crystal water finally setting a significant precedent for organic-inorganic hybrid electrodes for alkali ion batteries. All of materials were carefully analyzed via combined ex situ soft and hard X-ray absorption spectroscopy (XAS) analysis with in situ X-ray diffraction (XRD). Fundamental mechanism on this reversible phase transformation was theoretically elucidated and confirmed by kinetic investigation using first-principle calculation. These results provide deep insight into novel class of intercalating materials which can deal with highly reversible framework changes, and thus it can break up some typical prejudices which we have about the layered cathodes for Li or Na secondary batteries.
Tincone-New Hybrid Organic-Inorganic Anode Material for High Performance Li-Ion Battery
Authors: Zhu Hongzheng , Aboonasr Shiraz Mohammad Hossein , Liu Jian
Published: December 2020

Atomic layer deposition (ALD) is a nanomaterial synthesis method that draws more and more attention in the past few decades. Due to its self-limit growth nature, ALD has become a powerful tool for fabricating uniform and conformal thin film[1]. Molecular layer deposition (MLD), as a derivative of ALD, is a technique specially for organic or organic-inorganic hybrid films. Due to the carbon chains were involved [2], MLD thin film shows several more merits than ALD such as low growth temperature, flexibility and low density, which are very meaningful when applied in battery material. Studies of MLD film in battery field are usually focus on the following aspects. For example, applying MLD film as a post-treatment for electrode. In this way, MLD coating can suppress electrode volume change issue during discharge/charge processes because of its flexibility. [3] Secondly, if added an annealing process, MLD film with organic component would turn into porous carbon/metal oxide matrix. The post-anneal treatment would improve the contact between active material and conductive carbon, and also bring more site for heteroatom doping [4].

Although there are lots of studies of MLD film in battery field, only few researchers use MLD film as an organic electrode material. In our study, we synthesised Tincone MLD film on Nitrogen doped carbon nanotube (N-CNT), and test the electrochemical properties of this hybrid organic-inorganic anode material Tincone/N-CNT in Li-ion battery. As a result, Tincone film shows electrochemical activity in CV test, and good lithium storage ability in cycling test. The capacity retention of Tincone/N-CNT is 89% after 100 cycles. As a usage of MLD film for electrode material, Tincone/N-CNT enriches the ways of applying MLD method in battery field as well as energy storage area.

Keywords: MLD battery；Tincone；Lithium ions battery

References:

[1] Meng X , Wang X , Geng D , et al. Atomic layer deposition for nanomaterial synthesis and functionalization in energy technology[J]. Mater. Horiz, 2017, 4(2):133-154.

[2] Choudhury D , Sarkar S K , Mahuli N . Molecular layer deposition of alucone films using trimethylaluminum and hydroquinone[J]. Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 2015, 33(1):01A115.

[3] Luo, L.; Yang, H.; Yan, P.; Travis, J. J., et al. Surface-coating regulated lithiation kinetics and degradation in silicon nanowires for lithium ion battery. ACS Nano 2015, 9, 5559−5566.

[4] Chen, C., et al., Nanoporous nitrogen-doped titanium dioxide with excellent photocatalytic activity under visible light irradiation produced by molecular layer deposition. Angew Chem Int Ed Engl, 2013. 52(35): p. 9196-200.
Effect of Interfacial Activity on the Lithium Storage Behavior in Three-Dimensional Porous Host Electrodes
Authors: Yun Jonghyeok , Won Eun-Seo , Choi Seung Hyun , Park Min-Sik , Lee Jong-Won
Published: December 2020

Lithium-metal is considered a promising anode material for rechargeable batteries, owing to its high specific capacity of 3,860 mAh g-1 and low redox potential. However, various technical challenges, such as uneven Li deposition and large volume expansion, need to be addressed for the development of rechargeable Li-metal batteries. In recent years, there has been extensive research on the design and construction of three-dimensional (3D) porous electrodes that can host metallic Li. In practice, inhomogeneous nucleation and dendritic growth of Li still occur on top of the 3D host electrodes due to the kinetic limitation of Li+ in electrolyte-filled pores. In this work, we propose an interfacial activity gradient design to promote the bottom-up growth of Li in the 3D-Cu host electrode while suppressing the top growth. The Li plating behavior of the 3D-Cu host electrode is analyzed using a theoretical model based on a modified transmission line. Based on the theoretical results, a conformal lithiophilic nanolayer is formed via galvanic displacement to activate Li nucleation over the bottom, whereas an inert, non-conductive coating passivates the top surface. The 3D-Cu electrode with the interfacial activity gradient shows considerable improvements in Coulomic efficiency and cycling stability during repeated Li plating-stripping, compared to the conventional electrode with uniform interfacial activity. Our study demonstrates that the interfacial activity gradient design may provide an effective approach to developing highly efficient and robust Li metal electrodes based on 3D porous architectures.
(Invited) Ferroelectric Transistors for Synaptic Devices: Challenges and Prospects
Authors: Yu Shimeng , Wang Panni , Luo Yandong
Published: December 2020

Ferroelectric device based on HfZrOx (HZO) is an emerging non-volatile memory that is able to store multi-level weights of the deep neural network (DNN) models and enables the compute-in-memory paradigm. In this presentation, we will present our recent progresses in HZO based ferroelectric transistor (FeFET) design for inference as well as in-situ training. Hybrid synapse bit cell design, drain-erase scheme for 3D NAND array, and physical insights into minor loop history effect will be discussed and validated with 22nm/28nm FeFET experimental data. Then we will present our DNN+NeuroSim benchmark framework to evaluate the pros and cons of the FeFET technology for accelerating large-scale DNN models.
(Invited) Theoretical Understanding of Nanoscale Ferroelectric Field-Effect-Transistor Having a Poly-Domain Structure
Authors: Park Hyeon Woo , Hwang Cheol
Published: December 2020

The emergence of ferroelectricity in doped HfO2 and (Hf,Zr)O2 (HZO) thin film with a typical thickness ~10 nm brings back the great interest in ferroelectric (FE) memories including the conventional ferroelectric random access memory, ferroelectric field-effect transistors (FEFET), and more recent negative capacitance field-effect transistors, in not only academia but also memory industry. In the industry, one of the most important issues concerning a FEFET is whether FEFET based NAND (FE-NAND) memory can be a next-generation device with superior performance to a conventional CTF-based NAND memory. For this purpose, it must have the multi-level capability and lower interference between adjacent memory cells. Because of sufficiently large ferroelectric polarization (10~15 uC/cm2 for typical HZO thin film), the multi-level capacity of FE-NAND would be higher than that of CTF-based NAND. However, an experimental result of FE-NAND devices shows that only a tenth of the expected memory window for the reading operation was achieved. At the same time, ten times larger erasing/writing voltages are required.

In this work, we presented the comprehensive FEFET model to describe the writing process and reading process in FEFET from the fundamental viewpoint of metal-oxide-semiconductor (MOS) FET device physics in conjunction with the FE switching phenomenon. To capture the multi-domain nature of the ferroelectric thin film, we adopted the time-dependent Ginzburg-Landau (TDGL) formalism as a core physics of the switching kinetics. Furthermore, the FEFET model has been extended to a 3-Dimensional FE-NAND simulation. These models showed that the multi-domain nature of the ferroelectric film, which is shared by serial gates in the FE NAND device, not only degrades gate controllability on a target memory cell but also decreases a magnitude of surface potential. The extensive simulation results provided a critical view to understand the degraded memory window of FEFET and a possible strategy for the improvement.
(Plenary) The Revival of Compound Semiconductors and How They Will Change the World in a 5G/6G Era
Authors: Collaert Nadine , Alian AliReza , Banerjee Aritra , Chauhan Vikas , ElKashlan Rana Y. , Hsu Brent , Ingels Mark , Khaled Ahmad , Kodandarama Komal Vondkar , Kunert Bernardette , Mols Yves , Peralagu Uthayasankaran , Putcha Vamsi , Rodriguez Raul , Sibaja-Hernandez Arturo , Simoen Eddy , Vais Abhitosh , Walke Amey , Witters Liesbeth , Yadav Sachin , Yu Hao , Zhao Ming , Wambacq Piet , Parvais Bertrand , Waldron Niamh
Published: December 2020

Compound semiconductor devices have always intrigued the semiconductor industry due to their high intrinsic mobilities and the heterostructure engineering enabled by those materials. While CMOS has been the vehicle pushing the industry to ever smaller devices, better performance and of course reduced cost, the unique properties of compound semiconductor devices are finding renewed interest in an era where an increasing amount of data is being sent around, stored and analyzed. While several applications like photonics, high-power electronics and image sensors also benefit from enabling a variety of III-V materials and devices, specifically, in the RF Front-End Modules of 5G radio chips [1], these materials allow to address the challenges related to speed, efficiency and output power needed for this next generation wireless communication standard. And while 5G is in full deployment, with first addressing the sub-6GHz frequency bands and in a later phase the mm-wave frequency bands, first publications are already appearing on 6G, where even higher frequencies (beyond > 100GHz) will be targeted [2].

GaN [3] and InP-based devices [4] have a clear performance advantage over Si CMOS and SiGe HBT/BICMOS, but their lower integration potential, still restricted to smaller size substrates and lab-like processing today, is one of the key limitations for adopting those technologies for high-volume 5G and 6G applications. Upscaling those devices to a 200mm/300mm Si platform will be a first step to improve yield and maturity and increase complexity. In a second phase, upscaling and maturing these technologies will allow to co-integrate these devices, usually quite dissimilar to CMOS, with advanced Si technology nodes and provide a fully integrated heterogeneous system.

In this talk, we will review the status and progress toward integrating these devices on a CMOS-compatible platform.

References

[1] N. Collaert et al., "Semiconductor technologies for next generation mobile communications", 14th IEEE International Conference on Solid-State and Integrated Circuit Technology - ICSICT, pp. 1-4, Nov. 2018.

[2] White Paper from NTT Docomo regarding 6G, January 2020, [Online]. Available: https://www.nttdocomo.co.jp/english/binary/pdf/corporate/technology/whitepaper_6g/DOCOMO_6G_White_PaperEN_20200124.pdf

[3] U. Peralagu et al., “CMOS-compatible GaN-based devices on 200mm-Si for RF applications: integration and performance”, IEDM 2019, pp.398-401.

[4] A. Vais et al., “First demonstration of III-V HBTs on 300mm Si substrates using nanoridge technology”, IEDM 2019, pp. 178-181.
(Plenary) Creating the Interface between the Universe and Data with Integrated Photonic Sensors
Authors: Miller Benjamin L.
Published: December 2020

We are in an exciting period in history, as advances in our understanding of biology tell us how networks of DNA, RNA, proteins, and other molecules influence human health and disease. In order to detect all these molecules, measure their concentrations, and convert that into data that can be accessed digitally, we need the appropriate interface: a sensor. This talk will discuss the ways we are developing new optical sensor systems that can be used as diagnostic systems in the clinical lab, at the point of care, and (eventually) at home. Achieving these goals requires advances in chemistry, materials science, optics, and the fabrication technologies to make it all work “at scale”, in a format that can go beyond the laboratory and into the commercial sphere.

Integrated photonics is a particularly attractive option for building broadly useful sensor platforms. Here, the light source, sensing mechanism, and detection system are all in the same plane. As such, these sensors are small and simple enough that they could be incorporated into a cell phone. For the past five years, we have worked in partnership with the American Institute for Manufacturing Integrated Photonics (AIM Photonics) to establish designs and manufacturing strategies for photonic chemical and biological sensors. AIM is a public-private partnership established to develop US manufacturing capability in photonics. This talk will detail progress in demonstrating AIM Photonics’ fabrication capabilities in chemical and biological sensing, with a particular focus on rapid assays for SARS-CoV-2, the virus causing COVID-19 disease.
(Invited) GaN Power Electronics and Associated Fundamental Limits
Authors: Xing Huili Grace , Li Wenshen , Nomoto Kazuki , Jena Debdeep
Published: December 2020

How does it impact the design principles of power electronics in ultra-wide bandgap semiconductors? What fundamentally different roles does a p-region play in a power electric device in comparison to a semi-insulating region, for example, in the popular GaN HEMT based power transistors? What are the practical fundamental limits for the unipolar devices such as Schottky Barrier Didoes without the help of p-type? What are the unique advantages a polar semiconductor family like GaN can offer? What is polarization doping and how is polarization-doping fundamentally different from impurity doping? I will reflect on our efforts in seeking answers to these questions in the past 20 years in GaN power electronic devices as well as realizing state-of-the-art devices; some example publications can be found in references 1-12.

Our work has been in part supported by ARPAe SWITCHES, AFOSR FA9550-17-1-0048, and NSF DMREF 1534303, making use of shared facilities at CNF (NSF ECCS-1542081), CCMR (NSF MRSEC DMR-1719875) and equipment supported by DMR-1338010.

References:

[1] W. Li, Z. Hu, K. Nomoto, D. Jena and H. G. Xing. Compound Semiconductor, April/May Issue, Page 22-28 (2019). [2] P. Kozodoy et al., Journal of Applied Physics 87, 770 (2000); https://doi.org/10.1063/1.371939. [3] H. G. Xing et al, Proc. of 73rd DRC (2015) DOI: 10.1109/DRC.2015.7175549. [4] Z. Hu et al., Appl. Phys. Lett., 107, 243501(2015). [5] K. Nomoto et al., IEEE Electron Device Letters, 37(2), pp.161 (2016). DOI: 10.1109/LED.2015.2506638. [6] M. Zhu et al., Appl. Phys. Lett. 110, 182102 (2017); doi: 10.1063/1.4982920. [7] W. Li et al., IEEE Trans. Electron Dev. 64(4), 1635-1641 (2017). DOI: 10.1109/TED.2017.2662702. [8] Z. Hu et al. in Proc. of 75th DRC (2017). [9] W. Li et al, Appl. Phys. Lett. 113, 062105 (2018) DOI: 10.1063/1.5041879. [10] W. Li et al. IEEE Trans. Electron Dev. 65(6) (2018). DOI: 10.1109/TED.2018.2829125. [11] M. Meneghini et al., Phys. Status Solidi A, 1900750 (2020) DOI: 10.1002/pssa.201900750. [12] W. Li et al., J. J of Applied Physics 58, SCCD15 (2019) https://doi.org/10.7567/1347-4065/ab0f1b
(Invited) Epitaxy of Silicon Carbide for Power Devices
Authors: Myronov Maksym
Published: December 2020

We observe an evolution how electric power is generated, converted, distributed and used. The world making an attempt to move away from fossil fuels towards a more renewable, energy efficient and electrified energy ecosystems, and therefor efficiency in power conversion processes becomes critically important. As the most prominent example, various wide band gap semiconductor materials are entering the power electronics in electric and hybrid vehicles. Among them is a Silicon Carbide (SiC). A major benefit of its characteristics, comparing to Silicon (Si), in terms of switching speed, heat loss and size of power electronic devices, is at least 50 % reduction in energy loss in the form of heat. This saving translates into more efficient power electronics and more energy for an electric motor and therefore for longer mileage with the same battery. Therefore, SiC offers an opportunity to move power electronics beyond the boundaries set by the material limits of Si. From production point of view, SiC is especially attractive because of its compatibility with Si manufacturing technologies.

Modern semiconductor power electronic devices are fabricated out of epitaxial thin films of semiconductors, creating a desired device’s layers stack. Therefore, the epitaxy is absolutely essential for creation of such devices.

SiC is a fascinating material with excellent physical properties. It is a wide band gap semiconductor with high thermal conductivity. It is resistant to chemical etchants and radiation. It has high mechanical strength and biocompatible. SiC is the only Group IV compound semiconductor. And finally one of its polytypes, cubic silicon carbide (3C-SiC), can be grown on Si. There are over 200 polytpes of SiC. All of them are formed from 50% Si and C and consist of hexagonal SiC bilayers. Different stacking sequences of C-Si bilayers produces different crystal structures. Different polytypes have different properties and challenges. Due to this epitaxy is very challenging. Among all known polytypes only 3C-, 4H- and 6H- have been very well researched. Hexagonal polytypes of SiC such as 4H- and 6H-SiC already have commercial applications in power electronics and also used as substrates for gallium nitride (GaN). SiC substrates can be formed from these two polytypes, which can then be used for homoepitaxial growth at high temperatures for device applications. These substrates are extremely expensive, limited to 150 mm diameters and epitaxial growth requires very high temperatures (~1700-1800 °C), which are only achievable in specially designed, hot-walled chemical vapor deposition (CVD) reactors. 3C-SiC is the only polytype of SiC which possesses a zinc-blende crystal structure and can be grown on a Si substrate, below the Si melting point (1410 °C). Epitaxy state of the art and challenges for these polytypes and their application will be reviewed.
Sodium Ion Storage Based on a Na3V2(PO4)3 Cathode Achieves Ultrahigh Rate Capability and Cycling Life
Authors: Shin Kang Ho , Nakhanivej Puritut , Park Ho Seok
Published: December 2020

Due to high ionic conductivity of Na3V2(PO4)3 (NVP), stable three-dimensional structure and high theoretical capacity, NVP is attracting much attention as cathode material of Na-ion system. However, NVP has poor electronic conductivity which causes poor rate capability and cycle stability. The aim of this research is to further improve electronic conductivity and structural stability, thereby improving the rate capability and cycle stability. rGO has the characteristics of excellent electronic conductivity, large surface area, which make rGO a suitable material for the conductive network. Electrochemical tests show that NVP/rGO composites has much more excellent cycle stability and rate capability than pristine NVP. The results show that NVP/rGO can be considered as a candidate for cathode materials with high rate capability and stability in sodium ion storage systems and that forming a composite with rGO can improve rate & cycle performance of electrode materials.