bluuebunny/crossref_metadata_2025 huggingface dataset:
Improvement of Activation Processes for Lithium-Ion Secondary Battery through Electrochemical Characteristics
Authors: Kim Woojin , Shim Jae-Hyun
Published: August 2024

A lithium-ion secondary battery that has not undergone the activation process may experience compromised cycleability and safety. Therefore, the activation process following the manufacturing of lithium-ion secondary batteries plays a crucial role in enhancing safety and extending cycleability. Through the pre-charging process of the activation procedure, additives within the electrolyte undergo chemical reactions at the anode interface, forming a thin solid layer on the anode surface. The solid layer formed on the anode surface through this process is referred to as the Solid Electrolyte Interphase (SEI) layer. The SEI (Solid Electrolyte Interphase) layer serves to inhibit direct decomposition reactions between the electrolyte and the anode interface, similar to the role of a separator. It can contribute to long-term lifespan and safety. However, if formed beyond a certain thickness, the SEI (Solid Electrolyte Interphase) layer may go beyond the function of a separator and instead develop into a single, thick solid layer. Furthermore, if formed below a certain thickness, the SEI (Solid Electrolyte Interphase) may easily collapse, failing to fulfill the role of the solid layer and leading to issues of capacity loss and safety concerns. Therefore, the process of creating a robust SEI (Solid Electrolyte Interphase) layer with a consistent thickness, without deviation, is of utmost importance.

In this study, to enhance the activation process, a Double Layer Cell (DLC) with a capacity of 80 mAh was manufactured, and the State of Charge (SOC, %) during the pre-charging process was adjusted. To create a robust SEI (Solid Electrolyte Interphase) layer, the State of Charge (SOC, %) was maintained at 20%, 50%, and 80% after pre-charging at temperatures of 25°C, 45°C, and 60°C for a specified duration in each formation process. During these formation processes, impedance analysis (EIS) was employed to evaluate the resistance of the cell itself and the interface resistance in relation to changes in SOC (%) and temperature. Additionally, the crystal structure of the SEI was elucidated through XRD. Furthermore, chemical characteristics and bonding states of the cathode surface were analyzed using XPS. The morphology and composition of the SEI were observed through SEM and EDS, providing an analysis of the components of the SEI. Subsequently, the DLC was subjected to output verification through C-rate at room temperature based on SOC (%). The electrochemical characteristics were evaluated by measuring the cycleability of 1000 cycles at both room temperature and high temperature, assessing the impact of the pre-charging process.
Nickel Monoselenide (NiSe) Nanoflakes via Chemical Vapor Deposition Method for Lithium Storage
Authors: Wang Chiu-Yen
Published: August 2024

Nickel monoselenide (NiSe) nanoflakes with tens micrometer were grown on the SiO2/Si substrate by using the chemical vapor deposition (CVD) method. The two-zone tubular furnace was employed to control the temperature and vacuum of the growth area and the source area. Nickel(II) chloride hexahydrate powder (99.9%) and selenium powder were used as precursors and placed at upstream. The growth substrate, silicon with thermal growth oxide layer, was placed at downstream. Field-emission scanning electron microscope (SEM) and transmission electron microscopy were used to study the morphologies and microstructure of flake. The crystal structure of nanoflakes was characterized by XRD with Cu Kα radiation (λ = 1.5406 Å). The chemical composition of nanoflakes was analyzed with SEM attached energy dispersive x-ray spectroscopy (EDS). For the electrical properties study, the single NiSe nanoflake was transferred on the SiO2 /Si substrate with pre-patterned Cr/Pt (20 nm/50 nm) as electrodes. The NiSe nanoflakes were used as an anode material to study its’ lithium-ion batteries (LIBs) performance. Moreover, the discharge capacity of NiSe nanoflakes can retain as high as hundreds mAh g-1 after 50 cycles at a current density of 0.1 A/g, 97.5% of theoretical capacity. The electrical resistivityof a single nanoflake was about tens (μΩ·cm). The low electrical resistivity and high surface area of CVD grown NiSe lead to the NiSe nanoflakes could be a promising candidate for anode material of LIBs.
(Invited) Photon Upconversion: Getting Molecules and Nanocrystals to Talk Triplets
Authors: Tang Ming Lee
Published: August 2024

Photon upconversion offers the prospect of combining low energy near-infrared radiation to make high energy photons in the visible wavelengths to improve photovoltaics and introduce new bioimaging techniques. In order to harness the intrinsic ability of colloidal semiconductor nanocrystals to couple strongly with light, it is important to efficiently outcouple energy from photoexcited quantum dots (QDs), much like how nature uses molecular antennas to direct light during photosynthesis. This talk focuses on the organic-inorganic interface for triplet-fusion based photon upconversion, where orbital overlap between the QD donor and molecular acceptor is critical for efficient energy transduction. In the past 8 years, we have learnt a great deal about how the electronic interactions between chalcogenide nanocrystals and acene conjugated molecules affect the photon upconversion quantum yield. We apply the lessons learnt to extending photon upconversion to silicon nanocrystal light absorbers, addressing synthetic challenges with invaluable insight from time-resolved spectroscopy.
Interface Engineering in Gradient Core/Shell Quantum Dots Enables Efficient Photoelectrochemical Hydrogen Production
Authors: Zhang Hui , Bai Xiaoxia , Khosla Ajit
Published: August 2024

Semiconductor core/shell quantum dots (QDs) are considered promising building blocks to fabricate photoelectrochemical (PEC) cells for the direct conversion of solar energy into hydrogen (H2). However, the lattice mismatch between core and shell in such QDs results in undesirable defects and severe carrier recombination, limiting photo-induced carrier separation/transfer and solar-to-fuel conversion efficiency. Here, we explore an interface engineering approach to minimize the core-shell lattice mismatch in CdS/CdSexS1-x (x=0.09~1) core/shell QDs (g-CSG). As a proof-of-concept, PEC cells based on g-CSG QDs yield a remarkable photocurrent density of 13.1 mA/cm2 under AM 1.5 G one-sun illumination (100 mW/cm2), which is ~54.1% and ~33.7% higher compared to that in CdS/CdSe0.5S0.5 (g-CSA) and CdS/CdSe QDs (g-CS), respectively. Theoretical calculations and carrier dynamics confirm more efficient carrier separation and charge transfer rate in g-CSG QDs with respect to g-CSA and g-CS QDs. These results are attributed to the minimization of the core-shell lattice mismatch by the cascade gradient shell in g-CSG QDs, which modifies carrier confinement potential and reduces interfacial defects. This work provides fundamental insights into the interface engineering of core/shell QDs and may open up new avenues to boost the performance of PEC cells for H2 evolution and other QDs-based optoelectronic devices.
Synthesis and Characterization of Epitaxially-Fused Quantum Dot Superlattices at the Single Grain Limit
Authors: Abelson Alex , Qian Caroline , Law Matt
Published: August 2024

Epitaxially-fused superlattices of colloidal quantum dots (QD epi-SLs) may exhibit electronic minibands and high-mobility charge transport, but doing so requires epi-SLs with extremely high degrees of spatial and chemical (compositional) uniformity. In this talk, I will discuss both our efforts to understand and improve the epi-SL formation process, as well as recent charge transport studies on single epi-SL grains.

Epi-SLs are synthesized from a parent SL structure, typically composed of QDs with long insulating ligands. Over the past several years, we have developed insight into the physical and chemical mechanisms by which this parent SL structure is converted into an epi-SL. I will present detailed, multi-model structural characterization of the SL structures, which unveils the astonishing choreographic process by which millions of QDs rotate and translate, in concert, to form the epi-SL.

This structural transformation is initiated by chemical changes to the QD ligand layer, usually through manual introduction of liquids into the SL film. Mechanistic studies into this ligand-exchange process reveal a multi-step chemical sequence that initiates with a simple acid-base reaction. We exploit this insight to fabricate epi-SLs by means of photochemical triggering (using ultraviolet illumination) rather than alternative “hands-on” techniques which suffer from poor experimental control and pronounced chemical inhomogeneity and structural damage in the films. The use of light to trigger the SL conversion process enables much finer control in both the temporal and spatial domains, opening the door to much larger-area SL films and direct photopatterning of epi-SLs.

In the latter portion of the talk, I will present recent work charge transport studies in individual, highly-ordered PbSe QD epi-SL grains. One technical challenge in making these devices is the inherent mismatch in using traditional microfabrication techniques to make single-grained devices of air-sensitive materials. Here, we demonstrate the air-free fabrication of microscale field-effect transistors (μ-FETs) with channels consisting of single PbSe QD epi-SL grains (~ 1 -10 µm grain sizes) and analyze charge transport phenomena in these samples. The devices exhibit p-channel or ambipolar transport with a hole mobility as high as 3.5 cm2 V–1 s–1 at 290 K and 6.5 cm2 V–1 s–1 at 170–220 K, one order of magnitude larger than that of previous QD solids.
A Colloidal Route for Ubiquotous Mid-Wave Infrared Sensing
Authors: Ko Dong-Kyun , Al Mahfuz Mohammad M. , Islam Rakina
Published: August 2024

The rapid emergence of the Internet of Things, machine vision, and artificial intelligence have imposed critical requirements on the miniaturization, energy efficiency, and cost-effectiveness of infrared detectors. To meet these requirements, new sensor technologies that can reduce the fabrication cost associated with semiconductor epitaxy and remove the stringent requirement for cryogenic cooling are under active investigation. In the technologically important spectral region of mid-wavelength infrared (3–5 µm), colloidal quantum dots are currently at the forefront of this endeavor, with wafer-scale monolithic integration and Auger suppression being the key material capabilities to minimize the sensor's size, weight, power consumption, and cost (SWaP-C). Infrared sensors based on colloidal quantum dots have been studied for decades, and harnessing the interband transition in these quantum-confined nanostructures has been the mainstream theme in optoelectronic research. More unique photophysical properties can be harnessed by utilizing the transitions within the conduction levels or valence levels, known as intraband (intersubband) transitions. In this presentation, we discuss the progress, challenges, and opportunities of MWIR sensors fabricated from Ag2Se intraband colloidal quantum dots, a heavy metal-free colloidal nanomaterial that has merits for wide-scale adoption in consumer and industrial sectors.
Si1-XGex Alloys As Negative Electrodes for Li-Ion Batteries: Impact of Morphology in the Li+ Diffusion, Performance and Mechanism
Authors: Avila Cardenas Armando , Monconduit Laure , Haon Cédric , Herlin Nathalie
Published: August 2024

Si1-xGex alloys present interesting cycling performance as Li-ion anodes, owing to the synergetic effect from silicon’s high capacity and germanium’s electrical conductivity and Li+ diffusion. Various morphologies of Si1-xGex powders were obtained, micron-sized by ball-Milling (BM) and nano-sized by laser pyrolysis (LP) to study the effect of the morphology and composition on the electrochemical behavior. The electrical conductivity was measured and shows an increase with the Ge content, from 4.58E-03 for Si to 0.11 S m-1
for Si0.5Ge0.5. Half-cells were cycled at C/5, LP samples showed a better capacity retention than their BM counterparts (88% vs 72% at the 35th cycle for Si0.5Ge0.5). To rationalize these trends, Galvanostatic Intermittent Titration Technique (GITT) and Electrochemical Impedance Spectroscopy (EIS) were used to determine the apparent Li+ Diffusion in the Si1-xGex series. It was shown that the apparent Li+ Diffusion is dependent to the state of charge. Moreover, it gave insight about phase transformations during cycling. During lithiation, similar values (10-11
cm2 s-1
) were obtained for BM and LP Si0.5Ge0.5. However, a big variation (10-13 – 10-10
cm2 s-1) was found for the BM sample delithiation, which is attributed to the conversion of c-Li15(Si0.5Ge0.5)4 phase into amorphous Lix(Si0.5Ge0.5) (x<3.75). Asymmetric C-rate tests evidenced lithiation as the limiting mechanism for the Si1-xGex negative electrodes.

Figure 1
(Invited) Organosilicon Coatings Made By a Cold Plasma Processes at Atmospheric Pressure for Electrochemical Applications
Authors: Profili Jacopo
Published: August 2024

Cell manufacturing is estimated to account for up to 40% of battery-industry and the related market will grow 14.1% in the next five years (108.4 B$ in 2019). In this context, high-power and stationary large-scale energy storage systems, such as lithium-ion batteries (LiBs), will be essential to make electricity quickly accessible to the power grid. This is particularly true when it comes to power plants located in remote areas or the use of renewable energy sources. Despite their advantages, commercial LiBs are today limited by their environmental and safety hazards. These limitations lead researchers around the world to discover and employ new technologies for safe recycling operations and a better control of the cycling processes. Currently, works are focused on the development of new advanced materials, composite design as well as advanced interfacial layers. In this context, surface modification by cold plasma is one of the most promising solutions to control and modify charge transport mechanisms at the interfaces. Although, the synthesis of nano-layers made by plasma at atmospheric pressure has already received a lot of interest, their use to modify electrochemical devices, such as electrochemical cells remain limited. In this work, the synthesis of organosilicon coatings on composite conductive layers by atmospheric pressure DBD is studied in detail. The influence of different organosilicon molecules has been analysed to highlight the effect of the growth mode as well as chemical functionalities on the operation of the final electrochemical device. The physical and chemical modifications of plasma on the conductive layer as well as the water stability of the coatings were investigated by ATR-FTIR, XRD, SEM and contact angle.

Figure 1
Why Do Lithium-Ion Batteries Fail – a Case Study
Authors: Ha Yeyoung , Grocke Garrett L , Luu Norman S , Loewen Natalia D , Hirsh Hayley S , Bogart Timothy D , Beers Keith M
Published: August 2024

Lithium-ion batteries are everywhere – phones, laptops, cars, and many more. With their increased usage, battery failure incidents have also become more common. In this talk, I will discuss a failure mode that frequently occurs in consumer electronics containing pouch cells, referred to as “pouch grounding”. As the name suggests, this failure occurs when the aluminum layer of the pouch contacts a component surrounding that is connected to the negative electrode of the battery, which serves as the grounding source. Effects of temperature and humidity on the pouch grounding failure will be discussed along with cell teardown analysis to reveal the mechanism. This talk will be focused on introducing industry level understanding of lithium-ion battery failures and how industry and academia can collaborate to enhance the technology further.
Long-Term Calendar Aging across Commercial Lithium-Ion Cell Chemistries- Part I – Exploratory Data Analysis
Authors: Lam Vivek , Cui Xiaofan , Stroebl Florian , Uppaluri Maitri , Onori Simona , Chueh William C.
Published: August 2024

In this study, calendar aging is investigated across different cell chemistries, temperatures, and state of charges in a dataset spanning over 10 years. By tracking the capacity and resistance over the course of degradation, we analyze the similarities and difference in calendar aging seen across chemistries and testing conditions. We parameterize degradation curves using standard semi-empirical models to assess Arrhenius dependence, t^x fitting, and time dependent non-linearity of calendar aging across different chemistries, testing conditions, and cell to cell variability. Through this process we demonstrate the complexity of calendar aging and the difficulty of its modeling, calling for the need for more robust prediction models.
Using Three-Dimensional Carbon and Boron Nitride to Improve the Properties of Polyethylene Oxide-Based Solid-State Electrolytes for Li Ion Batteries
Authors: Wong Andrew Barnabas
Published: August 2024

Polyethylene oxide (PEO)-based solid-state electrolyte (SSE) is attractive due to its excellent adhesion with electrodes and good processability. However, lithium dendrites easily penetrate PEO because of their soft nature, which results in inferior battery performance and safety issues. In this talk, we will discuss the development of 3D (insulating) amorphous carbon and 3D amorphous BN to improve the properties of polyethylene oxide (PEO)-based solid-state electrolytes for Li ion batteries.

For the 3D amorphous carbon, we developed a novel self-healing PEO-based SSE is prepared by incorporating 2 wt% amorphous three-dimensional carbon (3DC). This SSE possesses suitably low electronic conductivity for battery applications (on the order of 10^−9 S/cm), which is five orders of magnitude lower than its ionic conductivity (10−4 S/cm) at 60 °C. In addition, the improved fluidity and strong adhesion between the 3DC and the PEO matrix contribute to the self-healing ability of SSE, which will repair the cracks of SSE formed during battery cycling. Moreover, this SSE shows enhanced ionic and thermal conductivities and mechanical strength, suppressing the formation and growth of lithium dendrites. As a result, this SSE exhibits excellent electrochemical stability, achieving 5000 h of stable cycles in lithium symmetric cell (0.1 mA cm−2, 0.1 mAh cm−2) and 850 long-term stable cycles for the LFP//Li full cell at 1 C (0.31 mA cm−2).

For the 3D amorphous BN, we have developed the first synthesis of powdery hexagonal boron nitride (h-BN). This synthesis introduces a novel NaCl-glucose assisted strategy to synthesize micron-sized 3D h-BN with a honeycomb-like structure. When incorporated into polyethylene oxide-based electrolytes for Li-ion batteries, 5 wt% of 3D h-BN significantly enhances ionic conductivity and mechanical strength. Consequently, this composite electrolyte demonstrates superior electrochemical stability; it delivers 300 h of stable cycles in the lithium symmetric cell at 0.1 mA cm-2 and retains 89 % of discharge capacity (138.9 mAh/g) after 100 cycles at 1 C in the LFP//Li full cell.

These two approaches reveal that 3DC and 3D h-BN can be used to improve the properties of PEO-based electrolytes of Li-ion batteries.
(Keynote) Science and Art of Additives for Electrodeposition of Soft High Magnetic Moment Alloys
Authors: Brankovic Stanko
Published: August 2024

Current trends demonstrate that electrodeposited soft high magnetic moment (SHMM) alloys will be the material of choice for fabrication of future magnetic nanostructures in magnetic recording, microelectronics, and MEMS technologies. The research in these areas is driven by the need for ultimately soft magnetic alloys with high magnetic moment, high electrical resistivity, good corrosion resistance and low stress levels. A common approach to achieve these properties is use and formulation of different additives. Our understanding of their effects/action is essential and has to be improved and quantified1,2.

In this talk, a review of the current state of the art in understanding of the additive action will be presented. This includes additive incorporation mechanisms3,4 and their relation to observed properties of SHMM alloys (CoFe, CoNiFe, and NiFe). Additive adsorption phenomenon is critically reviewed in correlation to stress in SHMM alloys, grain size, and surface morphology. Results and analytical models describing the effect of additives as a function of their formulation in the plating baths are discussed.

References:

1) E. I. Cooper, C. Bonhote, J. Heidmann, Y. Hsu, P. Kern, J. W. Lam, M. Ramasubramanian, N. Robertson, L. T. Romankiw and H. Xu, IBM J. Res. & Dev., 49, 103 (2005)

2) S. Riemer, J. Gong, M. Sun, I. Tabakovic. J. Electrochem. Soc., 156, D439, (2009).

3) S. R. Brankovic , R. Haislmaier, and N. Vasiljevic, Electrochemical and Solid State Lett. 10(6), D67 (2007).

4) J. George, S.-E. Bae, D. Litvinov, J. Rancheler, and S. R. Brankovic, Journal of the Electrochemical Society, 155 (9) D589 (2008).
Embedded Micro-Interdigitated Flow Fields for Efficient Intercalation-Based Desalination at Seawater Scale
Authors: Do Vu Q. , Reale Erik R. , Loud Irwin C. , Rozzi Paul G. , Tan Haosen , Willis David A. , Smith Kyle Christopher
Published: August 2024

During the past decade, intensifying water crises around the globe have motivated research in electrochemical desalination. Among such technologies, Faradaic deionization (FDI) has shown great promise for seawater desalination with the use of intercalation electrode materials that possess at least ten-fold higher charge storage concentration (~5 M) than seawater salinity (~0.5 M). Despite many efforts focused either on developing electrode materials or modifying flow-cell architectures, the promise of intercalative FDI was not previously realized experimentally. This work demonstrates for the first time salt removal approaching seawater-level salinity by using a flow cell containing symmetric cation intercalation electrodes separated by an anion-exchange membrane [Do et al., Energy Environ. Sci., 16, 3025–3039 (2023)]. We show removal of 96% of salt from ~500 mM NaCl feeds with ~50% water recovery at a thermodynamic energy efficiency (TEE) of 7%. In addition, the flow cell readily produces fresh water (< 0.017 M NaCl) from brackish water with 40% TEE and substantially lowered hypersaline brine concentration from 0.78 M down to 0.23 M at 11.7% TEE. We note that (1) scaling up the charge capacity of intercalation electrodes is crucial to improve salt removal in FDI and (2) rational design of flow-through electrodes is equally important to make FDI more energy-efficient by mitigating pumping energy consumption. Upscaling was achieved by using large-area electrodes with high areal loading of nickel hexacyanoferrate (NiHCF), up to 21 mg cm-2. Pumping energy was drastically reduced by embedding an interdigitated array of 70 µm wide channels into the NiHCF electrodes using laser micromaching to form novel embedded, micro-interdigitated flow fields (eµ-IDFFs). The dimensions of the eµ-IDFFs were tailored for our low-permeability electrodes based on analytical and numerical modeling, resulting in two orders of magnitude improvement in the apparent hydraulic permeability of these electrodes while minimizing active-material loss. Evidence of water transport between diluted and concentrated streams, as well as feed-concentration-dependent charge efficiency were reported, which potentially contributed to energy efficiency and water recovery losses, motivating their investigation to further improve FDI performance. In addition to their application toward desalination, the present eµ-IDFFs show promise for use in electrochemical energy storage and conversion processes that employ nanomaterials
(Invited) Electrifying Sulfate Waste for Gigaton-Scale Carbon Capture and Valuable Product Synthesis
Authors: Delima Roxanna , Lammers Laura
Published: August 2024

Travertine has developed an innovative process for gigaton-scale carbon capture and sequestration that leverages sulfate waste from the mining and fertilizer industries. alt-splitting electrolysis powered by renewable energy is used to convert sulfate waste and carbon dioxide into carbonate minerals and hydrogen gas at the cathode, and sulfuric acid at the anode. The resulting carbonate minerals serve as a sustainable precursor for green cement, while the sulfuric acid is employed to extract critical elements. An increased demand for critical elements over the next several decades (particularly for energy storage and fertilizer applications) will supply sufficient waste to permanently sequester CO2 at the gigaton per year scale. Notably, for every ton of sulfuric acid produced, 0.45 tons of CO2 are permanently sequestered as carbonate minerals. Travertine is currently designing a pilot system to capture 1 ton of CO2 per day, and the technology represents a transformative and economically viable solution to both climate change and resource sustainability.
(Invited) Electrochemical Marine Carbon Dioxide Removal (mCDR)
Authors: Loretz Jeremy
Published: August 2024

Ebb Carbon is developing an electrochemical system to safely remove carbon dioxide from the atmosphere and store it in the ocean as dissolved inorganic carbon. The core process uses bipolar electrodialysis (BPED) to process incoming seawater into aqueous acid and alkaline seawater. The acid is kept on land and used for beneficial purposes that result in its neutralization. The alkaline seawater is returned to the ocean, shifting the carbonate buffer system toward carbonate, resulting in the removal of CO2 from the air into oceanic bicarbonate as air-sea equilibration is restored.

For the mCDR system to be impactful on a global level, it must reach gigaton scale while being energy efficient and cost effective.The BPED stack dominates the energy demand of the system and is a prime design task for Ebb Carbon. The stack and system are undergoing development and testing in Ebb Carbon’s labs as well as at the labs of institutional partners. Combining all of these system elements requires a multitude of scientific and engineering disciplines to work together. In this talk, I will discuss the potential for improving the energy and Faradaic efficiencies of these systems, including the opportunity for collaboration with the electrochemical research community.
Reversible Carrier Concentration Control on Ultra-Thin in2O3 By Viologen Molecules Charge Transfer Method
Authors: Wang Sung-Tsun , Chen Jiun-Tai , Lien Der-Hsien
Published: August 2024

Ultra-thin Oxide semiconductor fabricated by atomic layer deposition (ALD) is one of the promising candidates, due to their ultra-thin thickness and being highly compatible with the silicon process.[1] However, further tuning the oxide semiconductor's carrier concentration is still an interesting issue. Although annealing is a widely used way, the increase in thermal budget is unwilling to be met. To adjust the carrier concentration without increasing the thermal budget, viologen molecule, a strongly n-type dopant which have been successfully applied to different material systems including 2D,[2] CNT,[3] ultra-thin Ⅲ-Ⅴ,[4] has been used in the In2O3 transistor(as shown in Figure 1a). After viologen treatment, the viologen dopants increased the carrier concentration and caused a difference of n
2D, which is 2 × 1012 cm-2 of 2 nm thickness in In2O3, without degrading the mobility under the same overdrive voltage. The In2O3 transistor achieves an electron sheet density of 6.8 × 1012 cm−2. To further expand the function, viologen dopants are modified by hydroxy group. With hydroxy group modifying, the viologen dopants can be removed by acetone and be re-treated back on the In2O3 again. The reversible cycle of viologen treatment can be repeated multiple times without harming the In2O3 device (as shown in Figure 1b). Precise control of the threshold voltage allows for fine-tuning of the transistor between depletion mode and enhancement mode. Based on this, a depletion load inverter has been demonstrated. This result shows that the viologen dopants and In2O3 have the potential to be further integrated with other low dimensional materials in BEOL without raising the thermal budget while tuning the carrier concentrations.

Figure 1. a) Schematic representation of the structure of a In2O3 bottom-gate transistor and the viologen charge transfer process. b) The transfer characteristics of In2O3 transistors repeatedly treated and removed of OHV for four cycles.

References

(1) Si, M.; Lin, Z.; Chen, Z.; Sun, X.; Wang, H.; Ye, P. D. Scaled Indium Oxide Transistors Fabricated Using Atomic Layer Deposition. Nat. Electron.
2022, 5 (3), 164-170. DOI: 10.1038/s41928-022-00718-w.

(2) Kiriya, D.; Tosun, M.; Zhao, P.; Kang, J. S.; Javey, A. Air-Stable Surface Charge Transfer Doping of MoS2 by Benzyl Viologen. J. Am. Chem. Soc.
2014, 136 (22), 7853-7856. DOI: 10.1021/ja5033327.

(3)Kim, S. M.; Jang, J. H.; Kim, K. K.; Park, H. K.; Bae, J. J.; Yu, W. J.; Lee, I. H.; Kim, G.; Loc, D. D.; Kim, U. J.; Lee, E.-H.; Shin, H.-J.; Choi, J.-Y.; Lee, Y. H. Reduction-Controlled Viologen in Bisolvent as an Environmentally Stable n-Type Dopant for Carbon Nanotubes. J. Am. Chem. Soc.
2009, 131 (1), 327-331. DOI: 10.1021/ja807480g.

(4) Takei, K.; Kapadia, R.; Li, Y.; Plis, E.; Krishna, S.; Javey, A. Surface Charge Transfer Doping of III–V Nanostructures. J. Phys. Chem. C
2013, 117 (34), 17845-17849.

Figure 1
Electromagnetically Enhanced Atomic Layer Deposition for Modification of Thin Film Properties through in Situ Substrate Biasing
Authors: Jones Jessica Catharine , Li Shi , Lagunas Vargas Francisco , Hood Zachary D.
Published: August 2024

Atomic layer deposition (ALD) is broadly used for thin, conformal film growth in microelectronics, photovoltaics, and other industries. Enhanced film properties are required for advancement of device performance. Use of electrical current in situ during deposition to drive material properties of films produced by ALD toward a desired state (such as higher conductivity) will increase the utility of thin film materials for device applications. In an ALD reactor bias is applied directly to substrates during ALD precursor pulses. Higher conductivity and growth rates were observed for samples grown with ALD enhanced by in situ substrate biasing. Thicknesses were determined via spectroscopic ellipsometry, uniformity was investigated by atomic force microscopy, and crystallinity by x-ray diffraction. These systems are computationally investigated to probe the mechanism by which the ALD processes are enhanced.
In Situ Transmission Electron Microscope Observation of Ruthenium Silicadation and Diffusion Behavior at Atomic Scale
Authors: Tsai Ming-Hao , Hou An-Yuan , Sung Hsin-Ya , Wu Wen-Wei
Published: August 2024

Ruthenium (Ru) has the excellent characteristics of oxidation resistance and good chemical stability; therefore, it has been widely used in semiconductor manufacturing, specifically in application as capping layers of extreme ultraviolet lithography (EUV) masks. The main purpose of capping layers is to protect Mo/Si multilayers from EUV radiation, preventing oxidation, damages, and contamination of the multilayers. However, with prolonged use, the EUV mask accumulates heat, resulting in diffusion between Ru and Si. When diffusion reactions occurred, leading to a reduction in the EUV mask's lifetime. In order to study the reaction mechanism, we use in-situ transmission electron microscopy (TEM) to observe the reactions between Ru and Si. In this study, Ru thin film was deposited on silicon substrate by electron gun (E-gun) evaporation. The dynamic formation process of ruthenium silicide has been observed via
in-situ TEM. During the heating process, Si atoms diffused into ruthenium thin film at 300 °C, at the same time, Ru atoms will also diffuse into silicon substrate. At 350 °C, due to the interdiffusion effect, Ru2Si is formed in the Ru thin film, and it is observed that Ru2Si3 is embedded in the Si substrate. As the temperature rises to 450 °C, Ru2Si was transformed into RuSi. Finally, at 600 °C, the Ru thin film completely transformed into Ru2Si3. We provide direct evidence of diffusion behaviors and formation mechanism of Ru-Si system for better investigation of EUV masks degradation processes in semiconductor manufacturing and design.

Keywords: Ruthenium silicide, in situ TEM, diffusion mechanism, atomic-scale, EUV mask

Figure 1. Structural identification of Ru thin film and in-situ heating process of ruthenium silicide formation. (a) Initial EDS mapping of as-deposited Ru thin film on silicon substrate, showing homogenous distribution of each elements. (b) HRTEM image of in-situ heating process during 350oC. (c) Magnified HRTEM image of Ru2Si indicated in blue frame in (b). (d) Corresponding fast Fourier transform (FFT) along [110] zone axis. (e) HRTEM image of in-situ heating process during 600oC. (f) Magnified HRTEM image of Ru2Si3 indicated in yellow frame in (e). (g) Corresponding FFT along [010] zone axis.

Figure 1
Selective Isotropic Dry Etching of SiO2 Using F/H-Based Pulsed Remote Plasma and a Vapor Phase Solvent
Authors: Lee Ji Yeon , Kim Dae Whan , Gil Hong Seong , Kim Doo San , Jang Yun Jong , Kim Dong Woo , Lee Jiyeon
Published: August 2024

Isotropic etching generally employs liquid-based wet etching techniques. However, due to the high integration of devices, conformal etching is challenging in patterns with a high aspect ratio because liquid chemicals struggle to penetrate inside the pattern. Additionally, during the drying process after chemical treatment, pattern collapse is observed due to surface tension. Therefore, there is a need for dry isotropic etching techniques to replace wet etching techniques in next-generation device manufacturing processes.

Typically, when high selectivity SiO2 isotropic dry etching is required, F-base/H-based gas mixtures are utilized to form HF, which serves as an etchant for SiO2. SiO2 can be dry etched through two different mechanisms. First, HF reacts directly with H2O or alcohol, etching SiO2. The other way is to produce (NH4)2SiF6 salt from the reaction of NH3, which can be formed in a plasma containing NH3 and NF3. This (NH4)2SiF6 salt is sublimated and removed by a following heating process at a temperature over 100ºC.

The process above has some disadvantages, such as lowering the etch selectivity of SiO2 over Si and Si3N4 because Si and Si3N4 can be etched by F radicals remaining in the plasma. This study aimed to overcome these disadvantages by controlling the F radical through pulsing the remote plasma during the discharging of F-based/H-based gas mixtures for the formation of HF. By pulsing the remote plasma, SiO2 could be selectively etched at a higher etch rate relative to those of Si and Si3N4. Additionally, various types of H/F-based gas mixtures that do not contain nitrogen while producing HF were investigated to prevent the formation of ammonium powders, which can be a source of contamination in the chamber. Futhermore, the etching mechanisms were identified through gas phase anlysis and surface analysis. Also, any possible surface damage during the etching process was investigated.
(Invited) Boosting Charge Transport of Polymer Semiconductors and Conductors through Nano Confinement Effects in Skin-Inspired Stretchable Electronics
Authors: Bao Zhenan
Published: August 2024

In this talk, I will discuss the roles of nano confinement effect on charge transport for polymer semiconductors and conductors induced by adding an insulating material in solution. This important phenomenon enabled development of polymer semiconductors and conductors with enhanced charge transport while adding stretchability or self-healing or biodegradable functionalities. This general method is not only important for skin-inspired electronics, but also for polymer electronics in general.
Investigating Ion-Coupled Electron Transfer of Conducting Polymers
Authors: Altuğ Fatma , Ülgüt Burak
Published: August 2024

After years of basic and applied studies of electron transfer in redox active films, the fundamentals of ion transfer during the exchange remain to be understood. Empirically, the processes are ion-transport limited. Using a conducting polymer as a model system, we aim to study the relationship between electron and ion transfer during redox switching.

We work on electrochromic conducting polymers because of their observable and detectable color changes in addition to the current during the redox switching. Tracing optical signals can enhance the understanding of electrical signals from redox reactions. When a potential is applied to the electroactive polymer, its color will change from lighter to darker or vice versa. Keeping in mind that absorbances are additive, the ratio of the contents that make up the overall color of the polymer changes. This ratio change is directly proportional to the amount of matter under inter-conversion during the redox reaction.

This study aims to explore the ion-electron mechanism in conductive polymers using the simultaneous Spectro-CV method. To achieve this, we conducted cyclic voltammetry at exceptionally high scanning rates, leveraging the conductive polymer's color-changing property. At these high rates, ion movement was restricted due to limited time for forward and backward motion, potentially reaching a point of stagnation. The investigation focused on whether the polymer would continue changing color, providing insights into ion-electron transfer. In addition, we are conducting EIS measurements alongside simultaneous Spectro-CV measurements and attempting to fit the impedance response of the polymer with an appropriate model. We aim to track the time constants provided by the polymer at different voltage values and understand the corresponding physical processes associated with these time constants. Additionally, we aim to use our EIS model to validate the desired redox current information obtained from optical data. We mathematically reach the faradaic portion of the total current with EIS and compare the results obtained from optical data.

References

[1] Nicholson, R. S., Shain, I. (1964). Theory of stationary electrode polarography. single scan and cyclic methods applied to reversible, irreversible, and kinetic systems. Analytical Chemistry, 36(4), 706–723.

2 Laviron, E. (1979). General expression of the linear potential sweep voltammogram in the case of diffusionless Electrochemical Systems. Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 101(1), 19–28.

3 Lyons, M. E. G. (1994). Electroactive Polymer Electrochemistry

Figure 1
(Invited) Ga2O3 Semiconductor Devices for High-Temperature Operation
Authors: Zakutayev Andriy
Published: August 2024

Beta phase of gallium oxide (Ga2O3) has attracted a lot of attention as an ultra-wide band gap semiconductor for applications in high-power electronic devices. High power operation often comes with increased temperatures of the devices due to joule heating, especially in semiconductors like Ga2O3with low thermal conductivity. However, electrical performance and reliability of the Ga2O3based diodes and transistors at very high temperature, above 400C, is not well established.

In this talk, I will present our recent experimental results on fabrication of Ga2O3semiconductor devices for applications as high-temperature diodes and hydrogen gas sensors. The fabricated Ga2O3/NiO p-n heterojunctions allow for device operation with >100-1000 rectification ratio up to 400-600C [1]. Despite the stable ultrathin Ohmic contact [2], the device performance degrades over tens of temperature cycles and hundreds of hours at these elevated temperatures, likely due to instability of the rectifying contact. We propose and implement alternative interfacial rectifying contact layers, that enable both high performance and long reliability of these high temperature Ga2O3 semiconductor devices.

[1] Sohel, Zakutayev et al Physica Status Solidi (a) 220 2300535 (2023)

[2] Callahan, Zakutayev et al J. Vac. Sci. Technol. A 41, 043211 (2023)
(Invited) Wbg and Uwbg Photoconductors and Applications
Authors: Voss Lars
Published: August 2024

Wide band gap and ultra wide band gap photoconductive semiconductors are of increasing interest for a number of applications including high power switching, high speed electronics, electromagnetic isolation, power electronics, and optical beam control. We will present work characterizing a number of semi-insulating semiconductors including GaN, SiC, Diamond, AlN, Ga2O3, their relative performance metrics, and examples of realized and proposed devices and applications. We will further discuss selection criteria based on first principles analysis for promising new photoconductors.
Gallium Nitride Electrodeposition at Indium Tin Oxide and Fluorine Tin Oxide Electrodes in Ammonium Nitrate and Gallium Nitrate Aqueous Solution
Authors: Leyva Aranzabal Mauricio A. , Cabrera Carlos R.
Published: August 2024

The potential of gallium nitride thin films in semiconductor technology and devices has garnered interest. This study aims to develop an effective GaN electrodeposition technique that will function on both Earth and microgravity situations and may be applied to any kind of needed application, such as in photovoltaic devices. To determine the optimal electrodeposition conditions, e.g. applied potential, cyclic voltammetry (CV) was done on a boron-doped diamond electrode at 0.01 mV/s potential scan rate and at 0.8 V vs. Ag/AgCl (Saturated KCl) constant applied potential. In the CV study, a well-defined peak formed at -1.75 V vs. Ag/AgCl (Saturated KCl). To start examining all the features of the electrodeposition of a thin film on Indium Tin Oxide (ITO) and Fluorine Tin Oxide (FTO) Electrodes, chronoamperometry (CA) measurements were done at different time scales, ranging from 3600s to 14400s and at a constant applied potential of -1.7 V vs. Ag/AgCl (Saturated KCl). The characterization methods used to examine the materials' topography, elemental contrast, crystal structure, and electrodeposition weight percentages included scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS). Longer electrodeposition times produced the best grain formation, promoting dendritic structure at the electrode surface. Furthermore, the optimal weight electrodeposition percentage of Ga and N was 10% and 35 % at 3600s, respectively, although the electrodeposited electrode surface was heterogeneous. The surface topographies at 3600s showed less grains definition and dendritic structures. At higher electrodeposition times, e.g. 14400s, more grain definitions and dendritic structures were found. For the 3600s electrodeposition time, XRD peaks were found at 33o, 37o and 46o, which are characteristics of GaN wurtzite structure according to literature.
(Invited) Scalable Manufacturing and Application of Piezoelectric Biomaterials
Authors: Wang Xudong
Published: August 2024

Piezoelectric materials are a group of important functional building blocks that interfacing the human body by coupling biomechanical energy and electricity. So far, many technology innovations have advanced piezoelectric materials and composites toward a broad range of biomedical applications, which possess unique biocompatibility and flexibility. Fundamentally, materials design and engineering draw the boundary where this technology may advance. In this talk, I introduce our most recent development of piezoelectric materials and composites that are particularly designed for implantable nanogenerator applications. First, I present our wafer-scale approach to creating piezoelectric biomaterial thin films based on amino acids. The self-assembled sandwich film and truss-like structures enabled both strong piezoelectricity and largely improved flexibility. Then, new ferroelectric composites are presented as a new material used in 3D printing for directly manufacturing of piezoelectric architectures with tunable piezoelectric and mechanical properties. Toward the end, novel applications of implantable piezoelectric materials are introduced, which enable the closed-loop electrostimulations for many biomedical therapeutics.

References:

J Li, C Carlos, H Zhou, J Sui, Y Wang, Z Silva-Pedraza, F Yang, Y Dong, Ziyi Zhang, T.A. Hacker, B. Liu, Y. Mao, X. Wang, Nature Communications 14, 6562 (2023).

J. Li, Y. Long, Z. Zhang, L. Wang, J. Sui, Y. Dong, Y. Wang, R. Taylor, D. Ni, W. Cai, P. Wang, T. Hacker, X. Wang, Science, 373, 337–342 (2021).
(Invited) Triboelectricity Based Self-Powered Sensing Towards Ecological Protection and Health Monitoring
Authors: Lai Chao Sung , Chakraborty Ishita
Published: August 2024

In recent years, the necessity for the evolution of effective research approaches to develop self-powered sensing networks has gained significant attention in view of their importance as the element of Internet of Things (IoTs) in the present scenario of global energy crisis and ecological dilemma. In these circumstances, triboelectric nanogenerators (TENGs) manifest remarkable potentiality and versatility in the eco-friendly approaches of self-powered sensing, considering their appreciable sensitivity to the environmental and applied conditions. By harvesting wasted energy, the triboelectricity based self-powered sensing networks exhibit promising prospect to be applicable in ecological protection and smart health monitoring by rapid detection of chronic diseases, as an effective step towards the wellbeing of human health and environment synchronically. In this talk, I will represent novel mechanisms for implementing the TENGs based on nano/micro-structured tribo-materials comprising polymer/semiconducting metal oxide composites and problematic waste materials into self-powered ultra-broadband photodetection, toxic gas sensing and early detection of chronic disease for the human health and environmental safety. This novel method for the instantaneous response of the triboelectric signals to the biomarker for specific disease provides a prospective framework for painless, rapid, very cost-efficient, and eco-friendly disease detection, which is anticipated to be widely preferred as more advantageous than some traditional methods owing to the convenience of both the patients and medical professionals. Additionally, the approach of reusing the problematic waste materials in these TENG devices presents an effective step towards the circular economy, in light of the environmental pillar of ESG (Environmental, Social & Governance).