bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electroless Deposition of Co-Mo-P (or B) Alloys for Ulsi Applications
Authors: Sverdlov Yelena , Shacham-Diamand Yosi , Shklovsky Jenny 
Published: February 2020

The purpose of this work was on the one hand to produce Co-Mo-P (or B) deposits and on the other to use our Co-P electrolyte as universal and to obtain Co-W-P or Co-Mo-P thin films from common solution. The Co-W-P electrolyte with sodium tungstate Na2WO4 or tungsten phosphoric acid H3[P(W3O10)4] as a source of W-ions was well studied. In this paper we present the process of Co-Mo-P (or B) electroless deposition from either sulfate and chloride bath at basic conditions using sodium hypophosphite or sodium borohydride as a reducing agent. The material and chemical properties of the obtained films were characterized. The paper focuses on the deposition process and study of electroless deposited films for using in microelectronic technology.
The Co-Mo-P and Co-Mo-B thin films were obtained from sulfate and chloride bath correspondingly. The refractory metal has been introduced to the solutions by adding molybdate ions.
The Co-Mo-P and Co-Mo-B were obtained by chemical method. The structure of electroless deposited Co-Mo-P (B) films was amorphous as determined by XRD analyze. By this is meant that barrier properties of electroless deposited Co-Mo-P(B) thin films are bound to be reasonably good. The resistivity of the deposited on Co-seed Co-Mo-P thin films with thickness of 60nm after annealing was 80 μΩ.cm. The resistivity of the Co-Mo-B layers with thickness of about 50-60 nm was 100 μΩ.cm and 38-40 μΩ.cm for Co and Cu seed, respectively. Co-Mo-P deposition process is less expensive as compared to Co-W-P deposition by reason of very low Mo-concentration in bath (0.1 g/l).

References

E.J. O'Sullivan, A.G. Schrott, M. Paunovic, C.J. Sambucetti, J.R. Marino, P.J. Bailey, S. Kaja, and K.W. Semkow, IBM J. Res. Develop., 42, p. 607 (1998).

F.Pearlstein, R.F.Weigman, Plating, 54, 714 (1967).

Physico-chemical origins of the chemical reduction of cobalt, K.M. Gorbunova ed., Science Publishing, Moscow (1974) (in Russian).

Y. Shacham-Diamand, Y. Sverdlov and N. Petrov, J. Electrochem. Soc., 148, C162 (2001).

5. Y.Shacham-Diamand, A.Zylberman, N.Petrov, Y.Sverdlov, Microel. Eng., 64, p.315-320 (2002)

Figure 1
Eletroless Plating of Copper on Graphite Powders for Homogeneous Copper-Carbon Composite
Authors: Lee Hyukjae , Chung Tai-Joo , Pyo Hyun-Uk 
Published: February 2020

DC motor brush facilitates current connection between moving parts and stationary wires in motor. Copper wire brushes are traditionally used in the past, but carbon brushes are more widely used in recent days. Although carbon brush offers high resistance and better commutation between commuter segments, it wears more rapidly than copper brushes due to its softness. New copper and carbon composite brushes have been developed to overcome this drawback of copper wire, however, the density difference between the carbon and copper results in inhomogeneity during mixing which causes poor sinterability and less than expected performance of the final product.
A simple way to bypass this problem is the coating of copper on carbon powder which easily reduces inhomogeneity caused by the density difference. In this work, copper is electrolessly plated on graphite powders and the effect of plating variables on the sintering behavior of the coated graphite powders. Prior to the electroless plating of copper, standard activation and sensitization procedures are applied to graphite powders using SnCl2-PdCl2 solution and PdCl2, respectively. For electroless plating of copper, formaldehyde is used as reducing agent of copper sulfate. Various ratios of amount of copper sulfate and graphite powder, pH, and plating times are tested to find the optimum condition for sintering of the coated powder. The results show that the copper coated graphite successively produces homogeneous sintered compacts, which shows improved sinterability as well.
Engineering the Magnetic Anisotropy of Electrodeposited Multilayers
Authors: Shirtcliffe James , Schwarzacher Walther 
Published: February 2020

Induced magnetic anisotropy is important in numerous technical applications. An in-plane easy axis may be induced in an electrodeposited alloy film by deposition in an applied field. The origin of this anisotropy is thought to be preferential alignment of pairs of atoms of the same species, and the effect is generally small compared to magnetocrystalline anisotropy or surface anisotropy. Despite the phenomenon being well established, many open questions remain, including what happens to the induced anisotropy as the film thickness is reduced, or what the minimum applied field required to induce anisotropy is. We have studied the induced anisotropy in electrodeposited Fe-Co-Ni(Cu)/Cu multilayers, and find that induced anisotropy is still observed for layer thicknesses down to 2nm. We have also shown that the field required to induce anisotropy in this system is extremely low. Furthermore, it is possible to engineer the anisotropy of the film as a whole by changing the direction of the applied field during growth.
Utilization of Hard X-Ray Photoelectron Spectroscopy for Silicon-Based Negative Electrodes Buried within Solid Electrolyte Interphase
Authors: Masuda Takuya , Aoki Nana , Iwai Hideo , Yoshikawa Hideki , Kondo Toshihiro , Uosaki Kohei 
Published: February 2020

Silicon is one of the alternative materials for currently used negative electrodes in Li-ion batteries because of its high lithium insertion capability. However, volume expansion of silicon-based active materials accompanied with the lithium insertion is a severe problem towards their practical application since this volume expansion can destroy both the silicon-based material itself and electrical connection composed of binders, current collectors and the silicon-based materials. Hence, understanding of the lithium insertion is essential to design the silicon-based negative electrode with a high tolerance to the volume expansion. However, these negative electrodes are buried with a thin film, so-called, a solid electrolyte interphase (SEI), which often prohibits the characterization of electrode surfaces.
X-ray photoelectron spectroscopy (XPS) is a surface-sensitive technique which can analyze the composition and oxidation states of elements within the sample surfaces, and often combined together with destructive ion-sputtering methods to obtain their depth profile. XPS utilizing hard x-rays, so-called HAXPES (Hard X-ray Photoelectron Spectroscopy), can be a complementary non-destructive technique to analyze a deeper region from the surface. Recently, we constructed an in-house HAXPES equipped with a Cr Kα (5415 eV) source for electrode materials buried within the SEI. Here, we compared “destructive” Ar ion sputtering-XPS and “non-destructive” HAXPES to characterize the depth profile of the SEI-covered Si(111) negative electrodes with and without lithium insertion.
(Invited) Control of Internal Plasma Parameters Toward Atomic Level Processing
Authors: Sekine Makoto , Tsutsumi T , Fukunaga Y , Takeda K , Kondo H , Ishikawa K , Hori M 
Published: February 2020

Plasma processes have been indispensable core technologies to manufacture ultra-large integrated circuits (ULSIs) and variety of devices, including MEMS and bio sensors. In order to develop the next generation devices, advancing of the plasma processes should be needed. However, the plasma processes have been developed based on the trial-and-error tuning of external parameters, such as electric power, gas pressure and gas flow ratio. Towards the surface processing with atomic level accuracy with extremely low damage, the precise control of internal parameters that actually define the surface reaction has become more important. Particularly, it is necessary to control the energies of species and eventually their chemical reactions on the surface directly. Furthermore, the spatiotemporally control of chemical species in gas phase in the processing is the key issue to obtain the high performance as well as establishment of the plasma science for manufacturing.
We have developed an autonomous plasma manufacturing system, which is able to measure radical densities with a compact monitoring system and control them at optimum values in real time. The spatiotemporal fluctuation of species in the plasma affects much on the surface reactions, which is fatal to fabricate nano-size, atomic level structures. Then, we can make nano-scale etching with an ultrahigh precision by employing the autonomous plasma system. [1] The plasma induced damages on the organic material and the method to realize the precise etching were clarified.
On the other hand, the wafer temperature has influenced considerably the process performances for the precise control of surface reactions. However, it was not dynamically controlled because the wafer temperature rises abruptly from the plasma ignition. Interactions between the plasma and the material surface at the beginning and the end of processing need to be considered as entirely different conditions. The temperature change should be minimized and kept in a specific range throughout the processing. We developed a feedback control system based on actual temperature monitoring in a real time by dynamical changes in plasma discharge on-off intervals. [2]
This presentation will emphasize the importance of the internal parameter control of species together with a wafer temperature in the plasma processing for the atomic level control and discuss the advanced plasma processes for ULSIs and GaN semiconductors. [3]
[1] H. Yamamoto, et al., J. Appl. Phys. 51 (2012) 016202.
[2] T. Tsutsumi, et al., Appl. Phys. Lett. 103 (2013) 182102.
[3] Z. Liu, et al., Jpn. J. Appl. Phys. 54 (2015) 06GB04.
Low Temperature Atomic Layer Deposited TiO2 Compact Layers for Planar Perovskite Solar Cells
Authors: Kim In Soo , Haasch Richard , Cao Duyen , Farha Omar K. , Hupp Joseph T. , Kanatzidis Mercouri , Martinson Alex B. F. 
Published: February 2020

Titanium dioxide (TiO2) thin films have been utilized in a wide range of applications in optoelectronics and solar energy conversion. In particular, TiO2 has been exclusively used in photovoltaic (PV) devices and photoelectrochemical (PEC) cells owing to its ability to efficiently transport electrons and passivate photoactive materials against aqueous media. However, TiO2 exhibits optimal transport properties in the crystalline anatase phase, and thus requires a high temperature annealing step at 500 °C, which significantly limits its application in temperature sensitive substrates (e.g. PET) or active materials (e.g. organic-inorganic hybrid perovskites). Moreover, while high resistance of TiO2 films necessitates the need for ultrathin films to reduce series resistance in PV devices, the synthesis of ultrathin pinhole-free TiO2 films remains a challenge through conventional deposition methods. To address these issues, TiO2 compact layers for planar perovskite PV devices were deposited via atomic layer deposition (ALD) – a chemically diverse vapor phase deposition technique with the capability to synthesize ultrathin pinhole-free films.
We have investigated the influence of low temperature atomic layer deposited (ALD) compact TiO2 layers as a function of post-treatment (i.e. O3, UV-O3, 500 °C) on the performance of planar perovskite PV cells. The performance of devices indicated variations primarily in open circuit voltage (VOC) and fill factor (FF) upon various forms of post-treatment. Changes in the VOC was mainly associated with the density of states within the bandgap of TiO2 as confirmed by X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). Also, low temperature post-treatment (O3 and UV-O3) resulted in reduced FF compared to the conventional high temperature annealing treatment as a consequence of decreased shunt resistance. We attribute this phenomena to the amorphous nature of the low temperature post-treated compact TiO2 layers providing channels for hole conduction. However, the devices fabricated with UV-O3 treated TiO2 compact layers resulted in a comparable overall performance compared to those fabricated with the conventional post-annealing process at 500 °C, opening possibilities for its application in temperature sensitive substrates as well as active materials.
The Origin of the Oxygen Redox Activity in Layered and Cation-Disordered Li-Excess Cathode Materials
Authors: Seo Dong-Hwa , Lee Jinhyuk , Urban Alexander , Ceder Gerbrand 
Published: February 2020

With increasing complexity of technology comes a demand for higher-energy density Li-ion batteries, which requires high-energy density cathode materials. Reversible oxygen redox in Li-excess materials can substantially expand the search space of high capacity and energy density cathodes, because it can deliver excess capacity beyond the theoretical transition metal (TM) redox capacity, reducing the necessity of heavy and expensive TM ions.[1-4] Nevertheless, the structural and electronic origin of the oxygen redox process is not understood, preventing the rational design of better cathode materials with oxygen redox.
In this talk, we explain how specific chemical and structural features in layered and cation-disordered Li-excess cathode materials introduce labile oxygen electrons that can be easily extracted and participate in the practical capacity of these materials. Our ab initio calculations demonstrate that Li excess and cation disorder create unhybridized oxygen 2p states in lithium-metal-oxide cathodes that promote oxygen redox, which can create extra capacity beyond the TM redox capacity and lead to peroxo-like species when local distortion in the chemical bond is allowed (Figure 1).[5] Furthermore, we explain how this specific oxygen redox process competes with the TM redox, providing clear guidelines for the design of high-capacity cathodes with optimized TM or O redox.
References
[1] H. Koga, L. Croguennec, M. Ménétrier, K. Douhil, S. Belin, L. Bourgeois, E. Suard, F. Weill, C. Delmas, J. Electrochem. Soc.
160: A786-A792 (2013).
[2] M. Sathiya, G. Rousse, K. Ramesha, C.P. Laisa, H. Vezin, M.T. Sougrati, M.L. Doublet, D. Foix, D. Gonbeau, W. Walker, A.S. Prakash, M. Ben Hassine, L. Dupont, J.M. Tarascon, Nature Mater.
12: 827-835 (2013).
[3] N. Yabuuchi, M. Takeuchi, M. Nakayama, H. Shiiba, M. Ogawa, K. Nakayama, T. Ohta, D. Endo, T. Ozaki, T. Inamasu, K. Sato, S. Komaba, Proc. Natl. Acad. Sci.
112: 7650-7655 (2015).
[4] J. Lee, D.-H. Seo, M. Balasubramanian, N. Twu, X. Li, G. Ceder, Energy Environ. Sci.
8: 3255-3265 (2015).
[5] D.-H. Seo, J. Lee, A. Urban, R. Malik, SY. Kang, G. Ceder, Nature Chem. in press (2016).

Figure 1
Synthesis of Layered MoS2 with Enlarged d-Spacing and Its Carbon Composite By Substrate-Induced-Coagulation Coating Method As Anode Materials for Lithium-Ion Batteries
Authors: Han Joong-Hee , Kahr Jürgen , Hamid Raad , Han Sung-Hwan , Ahn Do-Young , Trifonova Atanaska 
Published: February 2020

2D layer structured molybdenum disulfide (MoS2) has been considered as an alternative next generation anode material over graphite, hard carbon and metal alloys, because MoS2 is structurally analogous to graphite (0.335nm) and has the interlayer d-spacing of 0.615nm while exhibiting two or three times the specific capacity of graphite.
We will show how electrochemically active molybdenum disulfide (MoS2) with extended interlayer d-spacing was successfully prepared by the solvothermal synthesis method in an ethylene glycol-based mixed solvent at 200oC for 24h under an inert gas atmosphere. Then the prepared MoS2 samples were thermally annealed at various temperatures (300oC, 500oC, 800oC) to remove ethylene glycol from between the MoS2 nanosheets and to tune the d-spacing distance. The main redox reaction is described as Li2S ↔ 2Li+ + S + 2e-, and it suggests that the electrical conductivity of the MoS2 electrode must be enhanced by impregnation with carbonaceous materials to counteract the insulating properties of the sulfur. Therefore, the as-prepared MoS2 powders were surface- modified with nano-carbons (e.g. graphite and graphene) by the substrate-induced coagulation coating process and subsequent annealing at 600oC for 5h under the argon gas environment. The surface-modified carbon-MoS2 composite had a lithium diffusion coefficient (DLi: 1.08x10-6 cm2/s) during charging and discharging as compared to the as-prepared MoS2 (DLi: 4.14x10-7 cm2/s); the cell with the modified MoS2also exhibited higher capacity with a good capacity retention.
The carbon-modified MoS2 electrode showed an initial capacity of 1150mAh/g and an average specific capacity of around 900 mAh/g, comparing favorably to the as-prepared MoS2 (700mAh/g). The carbon-MoS2 composite showed a higher capacity with good capacity retention and higher rate capability. The cells were electrochemically characterized by cyclic voltammetry, rate capability measurements, electrochemical impedance spectroscopy, lithium ion diffusion coefficient (DLi) measurement, differential capacity measurements, and in-situ electrochemical XRD measurement.
In particular, the volumetric dilatation of the electrode materials during repeated cycles was monitored by in-situ electrochemical dilatometry. It was observed that the dilatations occur during charging /discharging, which corresponds to lithium inter-/deintercalation reactions at redox potentials of reduction at 1.1 V and oxidation at 1.6 V, 2.2V, respectively. The improved electrochemical properties of MoS2 tuned by the enlargement of the d-spacing and by the surface modification make it possible for MoS2to be used as a promising anode material for lithium-ion batteries.
Electrochemical Characteristics of Coal Tar Pitch Prepared By Chemical Activation for Lithium Ion Battery
Authors: Lee Jong Dae , Hwang Jin Ung 
Published: February 2020

In recent years, carbon-based materials have been extensively investigated as an anode material for Li-ion battery (LIB). Because of their low material cost, abundance, nontoxicity and good capacity, carbon materials have been considered promising materials for LIB anodes in portable electronic devices and electric/hybrid vehicles. Despite these advantages, the practical application of carbon-based materials in many electronic device and electric/hybrid vehicles is still limited by its poor
electrochemical performances
.
To enhance these electrochemical performances, we have performed the surface modification of coal tar pitch (CTP) by the
chemical activation with KOH and K2CO3

. Coa
l tar pitch (CTP) as an industrial by-product, composed of cyclical hydrocarbons of various molecular weights and configurations.
The preparation method has been optimized through the analysis of diverse experimental variables. The results obtained confirm the importance of the activating chemical agents to CTP ratio and the flow rate of gas during carbonization on the development of porosity. In addition, it shows that chemical activation with
KOH and
K2CO3

can be successfully used to develop CTP with high surface area and mean pore size.

In this study, the effect of
activating chemical agent
/CTP weight ratio, CTP particle size and vinylene carbonate (VC) as an electrolyte additive on electrochemical performances was investigated. The prepared modified CTP was analyzed by BET, XRD, FE-SEM and XPS. Also the electrochemical performances of modified CTP as the anode were investigated by constant current charge/discharge, cyclic voltammetry and electrochemical impedance tests in the electrolyte of LiPF6 dissolved in organic solvents(EC:DMC=1:1 vol%).
The coin cell using modified CTP(
KOH
/CTP =
1
:
5
in weight) has better initial capacity (421 mAh/g) than that of other composition coin cells. Also, modified CTP anode appeared a high capacity of 4
11
mAh/g on the second cycle and the retention rate capability of 2C/0.1C was
83
% after 30 cycle. It is found that prepared CTP anode showed improved cycling and rate capacity performance.
Graphene Modified Feof Nano-Structured Hybrid As Cathode Materials for Li-Ion Battery
Authors: Liu Yadong , Yang Fan , Xin Le , Ren Yang , Sun Chengjun , Liu Yuzi , Xie Jian 
Published: February 2020

Lithium-ion batteries (LIBs) are the major power sources for electronic and transportation applications due to their high specific energy, good cyclability and environmental friendliness. Intercalation compounds were commercially employed as the positive (cathode) electrode material. However, they have a limited capacity, which are not likely to meet the growing demand on specific energy and energy/power density. Transition-metal oxides, fluorides and oxyfluorides have attracted a lot of interest due to their ability to deliver high electrochemical specific energy arising from 2-3 electrons transferred. FeOF was proposed as a promising candidate1 because it has a high theoretical specific capacity, 885 mAh/g (3-electron process) and 590 mAh/g (2-electron process), leading to an exceptionally high specific energy of 1328 Wh/kg. However, the electrochemical performance of FeOF is drastically different in practice due to its low electronic conductivity and poor structure stability during charge/discharge cycling process.
To overcome these obstacles, conducting carbon matrices have been introduced to absorb the volume changes and to improve the structural stability of the electrodes. Graphene, a single−layer of sp2 carbon lattices, has been considered as one of the most attractive carbon materials for its excellent charge carrier mobility, mechanical robustness and thermal and chemical stability2. Our approach is to prepare a mixture of precursor of FeOF and graphene oxide in solution and to ensure a better bonding between FeOF and GO through a hydrothermal procedure. The resulted hybrid material showed much improved initial columbic efficiency and cyclability compared with the blank FeOF material. The initial specific capacity reached 621 mAh/g (Fig. 1) and the capacity retention was 78.9% (specific capacity 493 mAh/g) after 100 cycles at 0.1 C rate. It has been demonstrated that the performance improvement could be attributed to introduction of graphene which improved the electric conductivity and provide a substrate to stablize the FeOF particles by morphology observation and structure characterization. SEM (Fig. 2) and TEM were employed to observe the morphology change after introducing graphene. The structure evolution during charge/discharge process were also characterized by in situ XAS and high resolution XRD. The results showed that the graphene nano-sheets serve as substrates to stabilize the structure of FeOF and form a framework to stabilize the Fe clusters through bonding them to their original sites without migration. Thus, the FeOF/Graphene composite can keep the (de)lithiation reaction reversible during discharge and charge process.

Figure 1
Superior Li-Storage Performances of Liquid-Phase Exfoliated Two-Dimensional Gallium Sulfide Nanosheets/Single-Walled Carbon Nanotubes Flexible Composite
Authors: Zhang Chuanfang , Park Sang Hoon , Ronan Oskar , Harvey Andrew , Coleman Jonathan N , Nicolosi Valeria 
Published: February 2020

we have demonstrated the facile production of porous, binder-free gallium sulfide (GaS) NS/SWCNT flexible composite films via a liquid-phase exfoliation/vacuum filtration approach. As a LiB anode material, the composite film exhibits excellent rate capability, high specific capacity (838 mAh g-1) and a remarkably high utilization of GaS NS (1161 mAh g-1), demonstrating electrochemical performances competitive with those of other reported 2D MC-based electrode systems. This work opens up vast opportunities for other families of MC NS to be scalably processed into porous, binder-free, flexible conductive thin films and composites with a broad range of applications such as flexible electronics and optoelectronics, energy storage systems, sensors and fuel cells.