bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reliability of Post Plasma Oxidation Processed ALD Al2O3/Hf1-xZrxO2 Thin Films on Ge Substrates
Authors: Bhuyian Md Nasir Uddin , Sengupta Arijit , Ding Yiming , Misra Durga , Tapily Kandabara , Clark Robert D. , Consiglio Steven , Wajda Cory S. , Leusink Gert J. 
Published: February 2020

Germanium devices are widely investigated due to their high hole and electron mobility compared to that of silicon. Mobility above 300 cm2V-1s-1 has been reported for Ge PMOS. On the other hand, Ge NMOS showed poor drive current and low mobility in previous studies. This poor performance is attributed to the inability to form a good Ge/high-k interface (1). They also exhibit hysteresis during the capacitance voltage (C-V) sweep because of the presence of slow trap states near the dielectric substrate interface (2). Recently, the use of a slot-plane-antenna (SPA) Ar plasma during the deposition of ALD Hf1-xZrxO2 on Si substrate was reported to enhance the EOT (equivalent oxide thickness) downscaling potential with a suppressed trap formation in the bulk oxide under electrical stress (3).
In this work, we have investigated TiN/HfZrO/Al2O3/Ge gate stack using MOS capacitors with six different Zr/(Hf+Zr) content (0%, 25%, 33%, 50%, 75%, and 100%) in the dielectrics. The dielectrics were subjected to SPA plasma oxidation after the deposition process. Electrical characterization of these devices was studied in order to observe the impact of Zr addition in HfO2. The equivalent oxide thickness (EOT), flat-band voltage (VFB), interface state density (Dit), C-V hysteresis, and leakage current (I-V) behavior were analyzed. Figure 1 shows the comparison of EOT and VFB as a function of Zr content in the dielectrics. Figure 2 presents the C-V hysteresis data (to the left axis) and mid gap Dit (to the right axis) for these devices. The addition of Zr in HfO2 was found to enhance the EOT up to 75% Zr incorporation. These devices also showed lower hysteresis in the C-V characteristics. However, A reduction in EOT for these devices showed to increase the flat-band voltage shift (Fig. 1). While devices with 100% Zr showed the highest EOT value coupled with the lowest mid gap Dit, a reduction in EOT with Zr addition in HfO2 moderately increases the Dit (Fig. 2 to the right scale).

Figure Captions:

Fig. 1: Equivalent oxide thickness (filled squares to the right scale) and flat-band voltage (open triangles to the left scale) comparison for the addition of Zr in HfO2.
Fig. 2: Hysteresis behavior extracted from C-V sweep first from accumulation to inversion and then from inversion to accumulation (filled squares to the left scale) and interface state density by conductance method (open circles to the right scale) for ALD Hf1-xZrxO2/Al2O3 gate stacks on Ge substrate.

References:

1. Y. Ding, D. Misra, M. N. Bhuyian, ECS Trans., 69 (5) 313-322 (2015).
2. J. Lin, Y. Y. Gomeniuk, S. Monaghan et al., J. Appl. Phys., 114, 144105 (2013).
3. M. N. Bhuyian, D. Misra, K. Tapily et al., ECS. J. of Solid State Sci. Tech., 3(5) N83 (2014).

Figure 1
Lithium Recovery from Used Li-Ion Batteries Using Innovative Electrodialysis Method with Lithium Ionic Superconductor
Authors: Hoshino Tsuyoshi 
Published: February 2020

In recent years, the industrial importance of lithium (Li) has increased due to its use in Li-ion batteries. For example, large-sized Li-ion batteries are used as power supplies for electric vehicles and for storage of electricity in smart grids and smart houses. Therefore, a large amount of Li is required worldwide. The extraction of Li from used Li-ion batteries would allow a large amount of Li to be inexpensively acquired. The technology for recycling cobalt (Co) and nickel (Ni) from used Li-ion batteries has already been established. On the contrary, the technology for recycling Li from used Li-ion batteries is not yet established.
I have developed a method for the recovery of Li from seawater using a Li ionic superconductor functioning as a Li-ion separation membrane (LISM) [1]. Only Li ions were successfully recovered from seawater through the LISM; other ions in the seawater did not permeate the membrane. Therefore, I have developed an innovative new method for recycling Li from used Li-ion batteries using the LISM.
Figure shows the proposed Li recovery method. This innovative method involves the use of an LISM whereby only Li ions in a solution of used Li-ion batteries permeate from the positive electrode side to the negative electrode side during electrodialysis; the other ions, including Co, Al, and F, do not permeate the membrane. Li0.29La0.57TiO3 was selected as the LISM because it exhibits high durability against water. The positive side of the dialysis cell was filled with used Li-ion battery solution, supplied by DOWA ECO-SYSTEM Co., Ltd., Japan; the Li concentration of the solution was 2543.5 mg/L. Then the negative side was filled with distilled water. The applied dialysis voltage was 5 V, and electrode area was 16 cm2.
The calculation of the Li recovery ratios for this first of a kind electrodialysis technique with an LISM sheet was performed. The Li recovery ratio increased with electrodialysis time, reaching approximately 10% at 72 h of dialysis. The recovery ratios of Co, Al, and F were not calculated because the concentrations of Co, Al, and F were below the detection limit of inductively coupled plasma atomic emission spectrometry (ICP-AES).
After electrodialysis, CO2 gas was bubbled in the Li recovery water to produce lithium carbonate (Li2CO3) as a raw material for Li-ion batteries. The Li2CO3 deposition was easily generated by the reaction of CO2gas and the Li recovery solution as a lithium hydroxide (LiOH) solution.
This new method for recycling Li-ion batteries shows good energy efficiency and is easily scalable. Thus, this electrodialysis method is suitable for the recovery of Li from used Li-ion batteries.
[1] T. Hoshino, Desalination, 359, 59-63 (2015).

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Electrodeposition of Indium and Tin from Molten Chloride Electrolytes
Authors: Haarberg Geir Martin , Qin Bo , Martinez Ana Maria 
Published: February 2020

Recycling of electronic waste to recover the metal value is of prime importance, especially for metals with limited resources. An electrochemical approach should be an interesting option to develop sustainable recycling processes.
The electrochemical deposition of tin was studied by using cyclic voltammetry at glassy carbon electrodes in molten LiCl-KCl at 450 ℃. Tin deposition on the glassy carbon electrode was found to be diffusion controlled in molten LiCl-KCl containing 0.1mol% SnCl2. At higher anodic voltage, Sn2+ was oxidised to Sn4+. Metallic tin of high purity was obtained in potentiostatic electrolysis experiments. The current efficiency for deposition of Sn was as high as 95%.
The electrochemical reduction processes in molten LiCl-KCl eutectic containing InCl3, InCl2 and InCl were studied on glassy carbon electrode at 450 °C. The cathodic discharge of indium ions to form metallic indium was shown to take place by a consecutive two-step electrochemical process involving In3+, In+ and metallic In.
Metallic indium was deposited by constant voltage electrolysis in molten LiCl-KCl containing InCl3.
The electrochemical behaviour of ITO (indium oxide combined with 10 percent tin oxide) was studied in molten LiCl-KCl at 450 °C. The direct deoxidation of solid ITO was investigated by using different electrodes such as Mo wire and liquid zinc. An ITO covered glass electrode was investigated by electrochemical means in molten LiCl-KCl at 450 °C using Mo wire current collector. The findings, together with SEM and EDX analyses, confirmed that some ITO had been reduced.
Advanced Characterisation Techniques Applied to Battery Materials
Authors: Randjbar Daemi Sohrab , Shearing Paul R. 
Published: February 2020

Porous electrodes support a wide range of electrochemical and physical processes and are fundamental to the operation of a variety of battery types. While 1-dimensional models have been accurate in predicting cell performances at low cycling rates, they fail to account for degradation and ageing. These effects are directly relatable to the complex 3-dimensional nature of porous electrodes. Advances in X-ray computed tomography (CT) have allowed for the non-destructive imaging of a broad range of battery materials, with studies ranging from microstructural analysis to in-situ and in-operando characterisation. The availability of a variety of micro- and nano-CT instruments at the Electrochemical Innovations Lab at University College London, offers an unparalleled opportunity to characterize a variety of electrode materials across a range of length-scales, from 10s nm to 10s μm. The focus of this project is subdivided in analysing commercially available battery materials and materials used in next-generation batteries.
Because of the stable electrochemical performance of most commercially available electrodes, the analysis of these materials focuses on understanding how different calendering and manufacturing methods affect the electrode on the micro- and nano- length scales. Metrics such as the particles size and porosity distributions, or transport parameters such as the tortuosity factor are studied. Furthermore these material are used as a model to develop novel sample preparation methods as well novel miniature in-situ cells for X-ray imaging.
A novel laser micro-machining sample preparation method has also been developed. This can produce electrode pillars with diameters below 100 μm whilst maintaining the structure and directionality of the electrode, allowing for a clear identification of microstructural features and changes caused by the calendering process on the electrode. Figure 1 a) shows a virtual slice of a graphite anode micro-machined into a pillar and characterised with combined absorption and phase contrast imaging. Fig 1 b) presents a volume rendering of the graphite pillar along with the copper current collector.
For next-generation battery systems, there is a lack of in-depth microstructural studies that not only analyse and compare different types of electrode structures but also relate how these affect and are affected by battery performance and cycling. To increase the repeatability of the experiments and the representativeness of the obtained datasets, novel sample preparation techniques are developed. These studies have the aim of analysing a material, but also setting the basis for future work in which methods are devised for observing charged and discharged samples in inert and in-situ environments.

Figure 1
Synthesis and Magnetic Characterization of Nanostructured Silicon with Bi-Metal Filling
Authors: Rumpf Klemens , Granitzer Petra , Gonzalez-Rodriguez Roberto , Coffer Jeffery L , Michor Herwig , Poelt Peter 
Published: February 2020

The purpose of this work is to combine magnetic nanostructures of two different metals within nanostructured silicon to influence the magnetic switching behavior of the porous silicon/metal nanocomposite. Two routes are used to achieve such nanocomposites. The porous silicon templates are fabricated with a mesoporous morphology offering average pore diameters of 50 nm and these pores are filled with a bi metal filling, namely Ni and Co. The two metals are deposited alternatingly by electrodeposition. A further approach is the chemical growth of Co nanoparticles within porous silicon nanotubes (SiNTs) and the additional deposition of a Ni layer on the outer surface of the tubes (Figure 1). The inner diameter of the silicon tubes is around 50 nm and the wall thickness is about 10 nm. Since the silicon wall of the tubes offers a porous structure the Co particles, which are localized near the pore surface on the wall of a given nanotube, can touch the Ni layer. An alternative structure involves the deposition of an additional Si layer (after the growth of Co particles inside the tubes) as a spacer before the Ni deposition.
These samples have been characterized structurally and magnetically. The magnetic properties of the systems strongly depend on the size and shape of the deposited bi-metal nanostructures and also on the proximity of the Ni and Co structures to each other. If the distance is small enough magnetic exchange coupling between the two metal structures is present. Due to the size of the metal deposits and the coupling of the bi-metal structures the switching behavior of the hysteresis can be tuned. The aim is to achieve self-assembled nanocomposite systems with a high as possible energy product which can be promising for permanent nanomagnets.
Figure 1: SEM image of silicon nanotubes (SiNTs) with Co particles deposited inside the tubes and Ni covering the walls of the tubes.

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Watching Electrochemical Topography Change with Fast, High-Resolution Scanning Probe Microscopy
Authors: Kirchhofer Nathan D. , Proksch Roger , Revenko Irene 
Published: February 2020

Due to its exceptional sensitivity, scanning probe microscopy (SPM) enables detailed interrogation of surfaces and interfaces. However, when correlating spatial information to additional surface measurements (such as current, redox activity, force, electrical potential or conductivity, impedance, thermal mapping, viscoelastic parameters, and more), spatial resolution is often limited. Here, we present the development and demonstrate the utility of an Electrochemical (EC) Cell comprised of a sample stage, liquid cup, and cantilever holder that is housed in an environmentally-controlled sample chamber and may be interfaced with an external potentiostat. This EC Cell is employed on a high-resolution, fast scanning Cypher ES atomic force microscope (AFM) in different measurement modes, and enables detailed characterization of localized, electrochemically-controlled morphologies without sacrifices to spatial resolution (atomic resolution is routinely achieved). These EC-AFM measurements are presented and have bearing on the continued development of more-advanced metrologies such as electrochemical scanning tunneling microscopy (EC-STM), scanning electrochemical microscopy (SECM), electrochemical strain microscopy (ESM), and more.

Figure 1. The EC Cell and sample data. (A) Exploded view of the EC Cell. Top: cantilever holder. Middle: sample chamber. Bottom: liquid cup and sample stage. (B) Zoom view of the bottom of the cantilever holder showing the cantilever, clip, and "dipping" architecture. (C) Zoomed, exploded view of the liquid cup and sample stage assembly, including counter electrode. (D) Calcite atomic lattice, imaged in water with the EC Cell (5 nm scan). (E) Example temperature-modulated cyclic voltammetry study conducted with the EC Cell. (F) Example scan-rate-modulated cyclic voltammetry conducted with the EC Cell. (G) Time series of images collected through the Cypher ES top view optics showing deposition of copper on a gold surface during electrochemical reduction. (H) Cyclic voltammogram of copper deposition/stripping on gold, and series of AFM images (2 μm scan) of a copper crystal during stripping.

Figure 1
(Invited) Probing Local Electrochemical Functionalities at Solid-Liquid Interfaces
Authors: Kalinin Sergei V. 
Published: February 2020

Energy technologies of the 21st century require understanding and precise control over ion transport and electrochemistry at all length scales – from single atoms to macroscopic devices. Particularly of interest are electrochemical phenomena at solid-liquid interfaces, as a key element of classical and flow batteries, supercapacitors, sensors, and biological systems. At the same time, voltage modulated scanning probe microscopy techniques that have found broad applicability for probing reversible and irreversible electrochemistry and transport phenomena in solids cannot be directly applied in liquids, due to a non-trivial role of liquid electrolytes. In this presentation, I will illustrate several recent applications of SPM for liquid electrochemical imaging, ranging from Electrochemical Force microscopy, SPM – based dilatometry, and direct measurement of liquid layering in active devices.
This research was sponsored by the Division of Materials Sciences and Engineering, BES, DOE, and was conducted at the Center for Nanophase Materials Sciences, sponsored at Oak Ridge National Laboratory by the Scientific User Facilities Division.
Process of Formation of Porous Layers in n-InP
Authors: Quill Nathan , Clancy Ian , Nakahara Shohei , Belochapkine Serguei , O'Dwyer Colm , Buckley D. Noel , Lynch Robert P. 
Published: February 2020

The anodic formation of porosity in semiconductors has received considerable attention, due to the fundamental insight it offers into semiconductor etching properties and its wide range of possible applications [1]. Although a number of models have been proposed to explain the formation of porosity in semiconductors [2-5], none as yet can explain the complete range of structures which have been formed in different semiconductor-electrolyte systems.
The anodic etching of n-type semiconductors in the dark is limited by hole supply at the semiconductor surface. It is generally accepted that this limited hole supply is what causes the initiation and propagation of porous etching, with hole supply being enhanced (and hence, porous etching initiated) at defect sites at the surface [6]. The newly formed pore tips then act as sites for the continuous preferential supply of holes [5]. However, the variation in feature size, as well as the morphology observed, as experimental conditions are varied cannot be so readily explained.
We have developed a mechanism [7], based on our results for pore formation in n-InP in KOH, in which the variations in pore morphology are due to the competition in kinetics between hole supply, carrier diffusion at the semiconductor surface and the electrochemical reaction. The mechanism is represented schematically in Fig. 1. The mechanism can be used to explain the characteristic width of the pore structures, and their directional preference.
In this presentation we will review our recent results and show that they are in support of the mechanism [8-10]. We will also present the results from numerical modelling of pore formation in InP based on the aforementioned pore growth mechanism.

References

1. H. Foll, J. Cartensen, S. Frey, J. Nanomater. 1 (2006)
2. M.I.J. Beale, J.D. Benjamin, M.J. Uren, N.G. Chew, A.G. Cullis, J. Cryst. Growth
73, 622 (1985)
3. R.L. Smith, S.D. Collins, J. Appl. Phys.
71, R1 (1992)
4. V. Lehmann, H. Foll, J. Electrochem. Soc.
137, 653 (1990)
5. X.G. Zhang, J. Electrochem. Soc.
151, C69 (2004)
6. P. Schmuki, U. Schlierf, T. Herrmann, G. Champion, Electrochim. Acta
48, 1301 (2003)
7. R.P. Lynch, N. Quill, C. O'Dwyer, S. Nakahara and D.N. Buckley, Phys. Chem. Chem. Phys.
15, 15135 (2013)
8. C. O'Dwyer, D.N. Buckley, D. Sutton, S.B. Newcomb, J. Electrochem. Soc.
153, G1039 (2006)
9. R.P. Lynch, C. O'Dwyer, D. Sutton, S.B. Newcomb, D.N. Buckley, ECS Trans.
6, 355 (2007)
10. R.P. Lynch, C. O’Dwyer, N. Quill, S. Nakahara, S.B. Newcomb, D.N. Buckley, J. Electrochem. Soc. 160, D260 (2013)

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(Invited) Electrodeposition of Germanene
Authors: Stickney John Lewellen , Bui Nhi , Jung Jin , Reber Theodore James 
Published: February 2020

Germanene is the Ge analogue Silicene or Graphene. A number of ab-initio calculations in the literature suggest that Germanene sheets should exist. Those reports suggest that the material would have a buckled structure, where half the atoms are about 0.07 nm higher than the other half. Micro Raman, electrochemistry and in-situ scanning tunneling microscopy (EC-STM) have been used to better understand the electrochemical growth of Ge from aqueous solutions, from the first atomic layers on Au(111). Our initial studies of the electrodeposition of Ge resulted in some interesting, though not clearly understood results, such as why only about 2-3 ML of Ge could be formed by direct electrodeposition on Au, depending on the pH. Some reports in the literature indicate that thicker deposits of Ge can be formed by electrodeposition on electrode surfaces other than Au. It is not yet clear why Au would be different. In-situ STM studies of the first atomic layers of Ge have shown a number of processes which indicate that nanoscopic atomically flat layers are forming on the surface, which demonstrate that Germanene is being formed. Micro Raman has also demonstrated the presences of Germanene grown on Au(111), which displays a Raman band near 295 cm-1. These results will be described.

References

Liang, et al., Langmuir, 26(4) (2010) 2877-2884
Xuehai Liang and John L. Stickney, Chemistry of Materials, 23(7)(2011)1742-1752
Xuehai Liang, et al., J. Am. Chem. Soc., 133(2011)8199-8204
M. A. Ledina, et al., ECS Transactions, 66 (6) 129-140 (2015)
Resistive Switching Characteristics of Hydrogen Peroxide Surface Oxidized ZnO-Based Transparent Resistive Memory Devices
Authors: Simanjuntak Firman Mangasa , Pattanayak Bhaskar , Lin Chun-Chieh , Tseng Tseung-Yuen 
Published: February 2020

Transparent resistive memory technology has gained a huge interest in these recent years not only due to its potential application for future non-volatile memory but also due to its potential as an embedded device in wearable electronics.1 The impact of hydrogen peroxide treatment on the surface of ZnO film used for transparent resistive memory device application has been investigated. The surface oxidation was conducted by immersing the ZnO film into hydrogen peroxide solution. Switching characteristics of as-deposited and surface treated devices were initiated by double forming programming. Based on our previous result, superior memory performance can be achieved when the bipolar forming process is initiated to activate the switching behavior.2 However, in this experiment, such bipolar forming process cannot be performed on the as-deposited device (Fig 1a). Interestingly, after hydrogen peroxide surface treatment, the device is able to perform successful bipolar forming, thus, shows obvious switching characteristic (Fig 1b). Consequently, memory performance of surface treated device exhibits good endurance as compared to the as-deposited device (Fig 1c). The surface treated device demonstrates a stable switching with memory window (ON/OFF ratio) of about 7 times. This indicates that the thin oxidized layer at top electrode/ZnO interface plays a significant role in the device reliability. The defects concentration in the switching layer and the arrangement of the ionic conduction path may govern the formation and rupture of the conducting filament.3 Therefore, materials characterization and electrical conduction mechanism were conducted to explain the phenomena. This study offers a novel and simple method to enhance switching performance of the transparent resistive memory devices.
References
1. Simanjuntak, F. M., Panda, D., Wei, K. & Tseng, T. Status and Prospects of ZnO-Based Resistive Switching Memory Devices. Nanoscale Res. Lett.
11, 368 (2016).
2. Simanjuntak, F. M. et al. Enhanced switching uniformity in AZO/ZnO1−x/ITO transparent resistive memory devices by bipolar double forming. Appl. Phys. Lett.
107, 33505 (2015).
3. Simanjuntak, F. M. et al. Impacts of Co doping on ZnO transparent switching memory device characteristics. Appl. Phys. Lett.
108, 183506 (2016).

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