bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidence of a Magnetic Effect on the Electron Transfer of the Hydrogen Evolution Reaction (HER)
Authors: Knoche Krysti L. , Lee Heung Chan , Rathuwadu Nadeesha , Leddy Johna 
Published: February 2020

In 1972, Trasatti carefully compiled the rates of hydrogen evolution reaction (HER) on 31 metal electrodes near pH 0 [1]. The HER is a surface reaction that can be represented as
Hsoln⁺ ⇌ Hads⁺
Hads⁺ + e ⇌ Hads

∙

2 Hads

∙
⇌ H2,ads

H2,ads ⇌ H2,soln

Trasatti also defined the electrochemical work function Φ, which is the energy needed to remove an electron from the electrode surface to a redox species immediately at the electrode surface. The rates of the HER reaction are embedded in the standard exchange current density j0 (A/cm2) that measures the standard heterogeneous rate of electron transfer, k0. Trasatti demonstrated that plot of log j0 versus Φ yields two parallel lines as shown, where regression yields
log j₀ = (6.4₄ ± 0.2₄) Φ (eV) - (35.₄±1.₁) with R² = 0.98 for the higher rate line and
log j₀ = (6.5 ± 0.5₆) Φ (eV) - (38.₅ ± 2.₄) with R² = 0.93 for the lower rate line.
The slopes are the same but the intercepts differ by 3. For a given Φ, metals on the upper line have HER rates that are 1000 x higher than metals on the lower line.
In this presentation, the magnetic properties of the electrodes are shown to describe the binary segregation of the data into two discrete lines. The magnetic properties of the electrodes are set by paired and unpaired electron spins. The results are evidence of a magnetic effect on electron transfer.
References
[1] Trasatti, S. Work Function, Electronegativity, and Electrochemical Behavior of Metals. III. Electrolytic Hydrogen Evolution in Acid Solution. Electroanalytical Chemistry and Interfacial Electrochemistry 39, 163-184 (1972).

Figure 1
Mask-Free Selective Metallization on Glass By Controlling Surface Hydrophilicity
Authors: Wang Kuan-Ting , Wei Tzu-Chien 
Published: February 2020

The trend in selective metallization for printed circuit board (PCB) is to replace lithography process because of its process complication and cost waste. Nowadays, there are many ways to selective metal deposition, like ink-jet technique or laser irradiation for electroless metal deposition. In this study, we develop an unique, novel method to realize selective electroless metal deposition by controlling surface hydrophilicity without the need of tedious photomask process.
This technique is demonstrated by forming a superhydrophobic surface in the first step, and then laser patterning to allow bottom surface exposed. Those exposed surface was then metallized by a process involving “silane compound modification + nano-Palladium catalyst activation”. In particular, TiO2 nanoparticles is coated by spin-coating on the glass substrate. Then, the surface with TiO2 nanoparticles is modified by Perfluorooctyltriethoxysilane (PFOTES) in order to form a superhydrophobic surface. The water contact angle of the surface exceeds 150 degree at this stage. The superhydrophobic layer acts like a shelter that could prevent electroless plating reaction from the substrate surface. After that, laser beam is applied on the superhydrophobic surface to remove PFOTES/TiO2 so that the specific pattern is exposed. Finally, selective metallization is accomplished on the exposed surface using home-made Pd nanoparticles and commercial electroless metal solution.

Figure 1
Electrocatalytic Reduction of Carbon Dioxide Using Graphene/Cotmpyp-Based Coatings
Authors: Bochlin Yair , Korin Eli , Bettlehiem Armand 
Published: February 2020

The sharply rising level of atmospheric CO2 is one of the largest environmental concerns facing our civilization today. CO2 is the most significant greenhouse gas that has major effects on the environment such as global warming and ocean acidification. The conversion of CO2 back to useful compounds is a critical goal that would restore balance to earth’s atmosphere. CO2 reduction is possible through chemical catalysis, electrochemistry, photochemistry and biological processes. Chemical catalytic processes generally operate at high temperatures and pressures which lead to high energy cost. Electrochemical methods, however, operate at ambient conditions which offer a simple and effective route for CO2 reduction.
The electrocatalytic capabilities toward CO2 reduction of some cobalt porphyrins have been reported in the literature, although at considerable overpotentials and low current densities. The present work aims to assemble an electrocatalytic system composed of cobalt porphyrins and graphene derivatives. Spectroscopic, microscopic and electrochemical methods are used to analyze the interactions occurring between such porphyrins and graphene derivatives, and their effect on CO2 reduction. Such self-assembled systems are formed between 5,10,15,20-Tetrakis(1-methyl-4-pyridinio) porphyrin (CoTMPyP) and graphene oxide (GO). This combination was electrodeposited on electrode surfaces, from aqueous solutions, using concessive cyclic voltammetry scans. Cross-section TEM-EELS images found dense distribution of CoTMPyP between the graphene sheets throughout the coating (figure 1). This arrangement of dense cobalt porphyrins between large conducting graphene sheets leads to enhanced electrocatalytic activity and formation of liquid-phase methanol as determined from GC-MS analysis.
The electrodeposited CoTMPyP-GO system showed increased electrochemical activity toward CO2 reduction vs. water reduction (0.7 and 0.3 mA/cm2, respectively, at -1.2V vs. Ag/AgCl), as examined in aqueous 0.1 M Na2CO3 solution at pH 11.5.

Figure 1
Si-Ge Heterostructures Fabricated by Room Temperature Wafer Bonding
Authors: Razek Nasser , Dragoi Viorel , Jung Arik , von Känel Hans 
Published: February 2020

The newly developed technology EVG® ComBond® was used for the fabrication of Si-Ge heterostructures. In this technology, an ion beam bombardment is used to clean and to activate the Ge- and Si-surfaces at room temperature by removing the native oxides as well as organic contaminants without deteriorating chemical composition and microroughness of the surfaces.
After surface activation, the wafers were brought into contact at room temperature under high vacuum, which resulted in a wafer bond extending over the entire area.
The successful room temperature covalent bonding of Ge/Si with high bond strength (measured by the crack opening method), no micro-voids, and no thermal outgassing (inspection with scanning acoustic microscopy) was achieved. Cross-sectional transmission electron microscopy (TEM) of the bonded Ge/Si-interface revealed that the wafers bonded without damaging the crystal lattice except for a thin amorphous layer of <0.9 nm. This amorphous layer was completely removed by thermal annealing at 400°C for two hours. Current-voltage measurements on 1 cm2 samples made from p-Si/n-Ge wafer bonds revealed diode behavior with a ratio of forward to reverse current of >4 and a threshold voltage of around 0.3V. The forward current yields an ideality factor of 1.1 after correcting for the series resistance which consists of a contact and interface resistance.
Figure : High-resolution TEM image of Ge/Si interface after thermal annealing at 400°C for 2 hours shows no obvious oxide layer and amorphous layer between the wafers.

Figure 1
Modelling of Voltammetric Data from Electrochemical Capacitor Electrodes
Authors: Donne Scott W 
Published: February 2020

Many techniques have been used to characterize materials used in electrochemical capacitor electrodes. This includes the suite of materials science techniques to assess material structure, morphology, conductivity, etc., as well as various electrochemical techniques to assess material and electrode performance and cycling mechanisms. In the domain of electrochemical characterization methods techniques such as cyclic voltammetry and constant current charge-discharge cycling are used commonly to assess performance and gain an introductory insight into electrochemical mechanisms. Other techniques such as electrochemical impedance spectroscopy and step potential electrochemical spectroscopy also provide substantial mechanistic information.
This work is focused on enhancing the information that can be extracted from voltammetric data on electrochemical capacitor electrodes. Contributions to the overall current response are made from:
1. Capacitive processes, as modelled using the series combination of a resistor and capacitor;
2. Kinetically limited processes, as modelled using the Butler-Volmer equation;
3. Solid state redox processes, as modelled using an experssion derived from the Nernst equation; and
4. Electrode resistance
An Activated Bio-Carbon for Electrochemical Double-Layer Capacitors
Authors: Kim Yong-Il , Kim Jong-Huy , Baek Jeong-Hun , Lee Chan-Woo , Yoo Jungjoon 
Published: February 2020

An activated bio-carbon for electrochemical double-layer capacitor used commercialized potato starch powder as the starting material to produce high-purity spherical carbon using a hydrothermal synthesis method with various reaction times. Chemical activation of the KOH coated bio-carbon spheres was heat treatment from 700-900 °C. The activated bio-carbon activated at 900 °C exhibited as specific surface area of 1579.4 m2/g, average pore size of 2.9663 nm and pore size distribution was mostly concentrated in the range of 1.3–3.5 nm.
As results of the electrochemical characteristics for the electrode of activated bio-carbon synthesized for 12 hrs and activated at 900 °C, in 6 M KOH aqueous electrolyte, the specific capacitance variations were 160.6 F/g at 5 mV/s, 142 F/g at 100 mV/s, and 123.5 F/g at 500 mV/s.
(Invited) Atomic Layer Deposition and Etching of 2D Transition Metal Dichalcogenide Materials
Authors: Mane Anil U. , Choudhury Devika , Letourneau Steven , Elam Jeffrey W. 
Published: February 2020

Ultra-thin layer of two dimensional (2D) materials mainly transition metal dichalcogenide (TMD) semiconductor possess exceptional properties such as electrical, optical, magnetic, mechanical and chemical. This allows the exploration of internal quantum degrees of freedom of electrons and their potential for use in optoelectronic, energy, and sensor applications. At present, research on 2D-layered TMDs mostly rely on (i) flakes produced by exfoliation from bulk, (ii) synthesis by high temperature (800-1000oC) mostly by chemical vapor deposition or (iii) solution based methods. Although exciting results are being obtained, but all these methods have limitations such as poor quality of the material, lack of precise control of thickness, interface or ability to integrate them into complex 3D devices. Nevertheless, the biggest challenge in realizing their full potential has been the lack of doable material synthesis methods of such films with high uniformity, conformality and interfacing with other materials such as oxides and metals.
Among the various thin film growth methods, atomic layer deposition (ALD) offers the best combination of a controlled layer-by-layer growth of the material with high conformality and suitable integration with other oxides such as dielectrics and metals. At the same time, precisely control thermal-based etching method for 2D-TMD materials are needed. Secondly at present, there are tremendous attention and efforts on development of the thermal vapor based well control etching methods especially on atomic layer etching (ALEt). The successful combination of both ALD and ALEt of 2D-TMD can pave the way to control the synthesis of 2D-TMD layers over large areas. This will be important for 2D-TMD material integration for future successful large-scale complex device structures fabrication.
Here we will first discuss the ALD growth of 2D-TMDs (e.g. MoS2, HfS2 and MgS2) on metals (e.g. Mo, W and TiN), dielectric oxides (e.g. Al2O3, MgO, HfO2, and TiO2) and vice versa. Then precise control etching processes based on molybdenum hexafluoride (MoF6) and H2O vapor will be discussed. The MoF6-H2O precursors based etching process offer several advantages including low cost, low processing temperature, rapid and effective etching spanning the range from continuous etching to atomic layer etching (ALEt). We have used in-situ quartz crystal microbalance (QCM) and Fourier-transform infrared spectroscopy (FTIR) measurements to monitor the deposition and etching 2D-TMDs layers. Next, the deposited and etched 2D-TMDs thin films were analyzed by spectroscopic ellipsometry to determine the thickness and refractive index, and the composition was determined by X-ray photoelectron spectroscopy (XPS). These ex-situ measurements confirmed the 2D-TMDs deposition and etching behavior findings from our in-situ studies.
(Invited) High-Performance Si Optical Modulator and Ge Photodetector and Their Application to Silicon Photonics Integrated Circuit
Authors: Fujikata Junichi , Takahashi Shigeki , Mogami Tohru , Kurata Kazuhiko , Takenaka Mitsuru , Nakamura Takahiro 
Published: February 2020

We designed the optimum Si optical modulator (Si-MOD) structure with applying p-type-doped strained SiGe. By applying the strained Si70Ge30 layer, about twice larger optical modulation efficiency in VπL can be obtained in the simulation. In case of a relaxed Si70Ge30 layer, enhancement factor in VπL decrease to about 50%, but optical loss is comparable to that without a SiGe layer. We demonstrated a high modulation efficiency of 0.67 Vcm, which is about 50% more efficient than that of Si-MODs with just a lateral pn junction. From the Raman spectra and SIMS analyses, Ge composition of SiGe was estimated to be around 35%. Crystalline strain of SiGe was estimated to be 1.7% on the 0.04 mm2 square pattern, which is comparable to the theoretical value. On the other hand, it was estimated to be 1.1% for the selective growth of SiGe on the Si WG with a lateral pn junction. Therefore, biaxial strain of SiGe was a little relaxed, because the selective growth of SiGe pattern has a large aspect ratio with 400 nm width and 800 μm length. The Si-MOD showed 27.3 GHz bandwidth at -3 Vdc with 200μm-long phase-shifter. We demonstrated eye diagrams of NRZ (non-return-to-zero) 40 Gbps of 231-1 PRBS (pseudorandom binary sequence) and PAM (pulse amplitude modulation)-4 40Gbps at 1.3 μm wavelength under the condition of differential RF drive with 1.6-2.0 Vpp at -2Vdc. The optical loss of the Si-MOD is estimated to be 1.0-1.5 dB/mm, which is comparable to that of simulation. With increase in temperature up to 80℃, optical loss increased by about 0.3-0.5 dB, which would originate from band-gap shrinkage of a strained-SiGe layer. We obtained the clear eye diagram at 25 Gbps with 27-1 PRBS from the optical transceiver chip when the CMOS-driver output voltage was 0.9 Vpp and Vdc was -0.3V. ER (extinction ratio) of about 2 dB was obtained in case of 800μm-long phase shifter with 4-divided electrodes.
We also studied a high-speed and high-efficiency of surface-illumination type Ge photodetector (Ge-PD) with a 1800 nm thick Ge layer. By optimizing the anti-reflection coating stack structure, high responsivity of 0.8-0.9 A/W was uniformly obtained within the wafer. At 3 Vdc, about 15 GHz bandwidth was obtained. In case of the Ge-PD with thick Ge-layer, photo-carrier transit time mainly limits the frequency bandwidth. Therefore, we optimized the layered structure of Ge thickness on SOI to satisfy the high-responsivity and high-bandwidth. We demonstrated an output waveform from integrated CMOS-TIA (trans-impedance amplifier) at 25 Gbps with 27-1 PRBS at 1.3 μm wavelength at 3.3 Vdc. Clear eye opening was obtained, which would contribute to the efficient optical interconnect.
(Invited) Organic Thermoelectric Materials and Devices Enabling New Thermal Management and Conversion Technologies
Authors: Yee Shannon K. 
Published: February 2020

Within the last 3 years, thermoelectric technologies have seen renewed global deployment providing unique solutions to pressing thermal problems. Today thermoelectric technologies are helping to ensure vaccines viably reach the most remote locations in the world, are providing personal comfort in wearable devices addressing medical circulatory conditions, and are being designed for integration into electric vehicles thereby reducing the global warming contributions of refrigerants in conventional air conditioning systems. The majority of these technologies have resulted from innovative engineers utilizing conventional materials in niche applications. However, additional societal contributions can be achieved by leveraging the large-area processability and abundance of polymer-based thermoelectrics.
Unfortunately, the material performance of polymer-based thermoelectric materials is lacking compared to their inorganic counterparts. To circumvent this challenge, composites or hybrid organic-inorganic materials are often employed in functional devices. Furthermore, while there is an abundance of p-type materials to select from, there are few air-stable n-type thermoelectric materials. Metal coordinated polymers (or metallo-organic polymers) are one promising class of thermoelectric materials where a metal (or semimetal) atom is present along the polymer backbone. This structure produces periodic centers of high electron density, which, when coupled to the vibrational modes (e.g., vibrons or phonons), could result in appreciable power factors. Both air-stable p-type and n-type metal coordinated polymers can be readily synthesized from abundant materials and are promising scalable alternatives to inorganics that leverage solution processing.
This invited talk will first provide a motivating overview of emerging thermoelectric technologies being developed through the Scalable Thermal Energy Engineering Laboratory (STEEL) directed by Prof. Shannon Yee at the Georgia Institute of Technology. Next, this talk will discuss progress in synthesizing and controlling the thermoelectric properties of poly(nickel-ethenetetrathiolate) (i.e., Ni-ETT) and poly(nickel-tetrathiooxalate) (i.e., Ni-TTO), which are both air-stable n-type thermoelectric materials containing nickel along the polymer backbone. Next, this talk will discuss recent on-going work studying p-type chalcogenophene polymers, where the isovalent series of polythiophene through polytellurophene will be discussed. Finally, this talk will introduce new thermoelectric device architectures, specifically printable, that are enabled by these materials. Throughout this talk emphasis will be placed on the engineering and scaling challenges, which have been overlooked in the pursuit of high performance materials, but are most critical to realizing thermoelectric devices.
Plasma Deposited Metal-Oxide Nanosensors for Amine Detection
Authors: Filipič Gregor , Gruenwald Johannes , Puliyalil Harinarayanan , Zavašnik Janez , Cvelbar Uros 
Published: February 2020

The metal-oxides have raised significant scientific interest in recent years, due to their sensing properties. In is notable that the gas sensing properties can be enhanced by structural and morphological manipulation of the sensor. Previously was demonstrated that increasing the sensor surface to volume ratio during synthesis with formation of sheet-like structures or nanowires can enhance the sensor sensitivity [1,2]. Among different oxides, cuprous oxide is interesting due to its wide band gap and stability [3]. Cuprous oxide nanostructures can be synthesized by different methods ranging from solution based chemical methods to thermal and plasma synthesis [4]. However one of most optimal in terms of time, simplicity and quality of synthesized nanostructures is plasma processing, especially at atmospheric pressures. For this reason, the atmospheric DC plasma source was used for deposition of CuO nano-sheets on the surface of copper electrodes [5,6]. The prepared samples were then used to detect different amines (diethylamine, trietylamine, cyclohexanamine) which are present in vapours generated in spoiled food and many industrial processes. These chemical substances are cancerogenious and represent serious health hazards to humans. The developed gas-vapour sensor exhibited an excellent resistive sensitivity for these chemicals even at temperatures below 100 °C. In performed evaluation analysis, the morphology of the CuO nanostructures was changed, but results demonstrated that sensitivity is preserved during morphological changes as long as crystallinity remains similar, and the sensor material is of nanosize-dimension at least in one direction. The obtained results were explained by theoretical investigation of sensor performance.
[1] S. Steinhauer et al., Sensors and Actuators B: Chemical, 187 (2013), 50-57
[2] C. Yang et al., Sensors and Actuators B: Chemical, 207 (2015), 177-185
[3] M. Hübner et al., Sensors and Actuators B: Chemical, 153 (2011), 347-353
[4] G. Filipič et al., Nanotechnology, 23 (2012), 194001
[5] J. Gruenwald et al., Plasma Processes and Polymers, 13 (2016), 946-954.
[6 ] J. Gruenwald et al., Plasma Processes and Polymers, 13 (2016), 766-774
(Invited) Low-Temperature Activation Method for InGaZnOx Thin-Film Transistors
Authors: Furuta Mamoru , Mehadi Aman S G , Magari Yusaku , Daichi Koretomo 
Published: February 2020

Metal oxide thin-film transistors (TFTs) have attracted considerable attention for use in next-generation high-definition and large-area flat-panel displays (FPDs) owing to their excellent electrical properties such as high mobility (>10 cm2/Vs), large-area uniformity, and compatibility with low-temperature process. An InGaZnOx (IGZO) is widely employed as a channel material of oxide TFT. Although an IGZO film can be deposited by sputtering without an intentional substrate heating, an IGZO TFT requires a post-annealing around 300°C due to the recovery defective states induced during the sputtering process. A post-annealing required for improving TFT characteristics and reliability is often named as “activation annealing”. The activation annealing around 300°C limits the fabrication of oxide TFTs on flexible substrates. Several activation methods for oxide semiconductor, such as simultaneous UV and thermal annealing, electrical assisted thermal annealing, and high-pressure annealing, have been proposed to reduce annealing temperature at ~150°C. Another approach is an improving film quality of the sputtered IGZO.
In this presentation, a new method to achieve high quality sputtered IGZO film will be presented. Proposed deposition method reduced density of states near conduction band, and could reduce an activation annealing temperature to 150°C. Detail mechanism to achieve low-temperature activation of IGZO TFT will be discussed.