#1 - Adaptive Scalpel Scanning Probe Microscopy for Enhanced Volumetric Sensing in Tomographic Analysis
Md Ashiqur Rahman Laskar
Controlling nanoscale tip-induced material removal is crucial for achieving atomic-level precision in tomographic sensing with atomic force microscopy (AFM). While advances have enabled volumetric probing of conductive features with nanometer accuracy in solid-state devices, materials, and photovoltaics, limitations in spatial resolution and volumetric sensitivity persist. This work identifies and addresses in-plane and vertical tip-sample junction leakage as sources of parasitic contrast in tomographic AFM, hindering real-space 3D reconstructions. Novel strategies are proposed to overcome these limitations. First, the contrast mechanisms analyzing nanosized conductive features are explored when confining current collection purely to in-plane transport, thus allowing reconstruction with a reduction in the overestimation of the lateral dimensions. Furthermore, an adaptive tip-sample biasing scheme is demonstrated for the mitigation of a class of artefacts induced by the high electric field inside the thin oxide when volumetrically reduced. This significantly enhances vertical sensitivity by approaching the intrinsic limits set by quantum tunneling processes, allowing detailed depth analysis in thin dielectrics. The effectiveness of these methods is showcased in tomographic reconstructions of conductive filaments in valence change memory, highlighting the potential for application in nanoelectronics devices and bulk materials and unlocking new limits for tomographic AFM.
#2 - Demonstration of Co/Ni Exchange in LiCoO2 Nanosheets: A New Approach for Upcycling Spent Li-ion Battery Cathodes
Hsin Juei Wang
In response to growing concerns over the limited availability of cobalt sources for lithium-ion battery cathodes, this study explores a novel method for upcycling LiCoO2 (LCO) materials. Traditional approaches for LCO recycling, such as pyrometallurgy and hydrometallurgy, are known for their energy-intensive processes. Here, we propose a new direct upcycling approach that leverages the high surface area of LCO nanosheets to facilitate cobalt extraction and cation exchange. The method involves exfoliation of the LCO into nanosheets, where are then mixed with aqueous solutions to promote cation exchange. The effectiveness of cobalt extraction and its replacement by nickel is investigated using various characterization techniques, including Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction and soft X-ray absorption spectroscopy. In addition, the reassembly of the nanosheets into functional cathode materials is also accomplished using heat treatment. The results show the successful synthesis of Ni-doped LCO (LiCo1-xNixO2, x = 0.11) using this approach. Moreover, Mn ion exchange into the exfoliated LCO is also investigated with the same method. This study establishes how nanosheet processing can be leveraged for recycling critical materials used in batteries and establishes a new pathway that can be used for converting LCO or low-Co materials to Ni-rich cathodes.
#3 - Material Quality Assessment of IGZO via Computer Vision-Assisted Conductive Atomic Force Microscopy
Md Jayed Hossain
Indium-Gallium-Zinc Oxide (IGZO) is a promising n-type semiconductor oxide, renowned for its exceptional electrical and mechanical properties, including high mobility, wide bandgap that enables transparency, as well as excellent electrical stability and flexibility. Consequently, it is emerging as a strong candidate for multiple applications including display technology, back-end-of-the-line (BEOL) compatible logic, and memories, thanks to its low thermal budget and compatibility with CMOS architecture. However, being a ternary alloy IGZO has a rich multitude of phases, and a major challenge lies in the costly and complex characterization for the material screening and process control. In this work, we report on the use of conductive atomic force microscopy (C-AFM), a powerful technique for the rapid screening of electrical properties of blanket IGZO films. This is enabled by the application of computer vision algorithms to classic C-AFM data acquisition. The results indicate that major material parameters can be extracted automatically, while maintaining nanometric resolution for the electrical features. Finally, we leveraged the power of computer vision and automation offered by Phyton scripting to analyze the results obtained from the raw C-AFM images, enabling accurate and automated assessment of IGZO samples. This approach allowed us to extract key parameters such as conductive spots, highly conductive areas, coverage percentage, and average current on the sample surface.
#4 - Layer Stacking-induced Light Orientation via Vat Photopolymerization for Optical Steganography
Tengteng Tang
This research investigates vat photopolymerization (VPP) as a technique to fabricate high-performance polarizers that can encode and decode hidden optical information, vital for secure information storage and transmission. The study aims to advance both additive manufacturing and optical steganography by exploring optimal process parameters, material selections, and specific refinements to enhance anisotropic properties in polarizers. A critical aspect involves understanding how layer-based VPP influences the polarization properties of the printed structures, which is key to controlling anisotropy. The methodology focuses on optimizing VPP parameters such as layer thickness and exposure duration to precisely manage the polarization characteristics. This includes fine-tuning material compositions to achieve desired polarization effects. The research also entails a comprehensive evaluation of the mechanical properties of the polarizers to assess their durability and functionality under real-world conditions. By utilizing the advanced optical characterization equipment at the Eyring Materials Center and applying these advanced polarizers in optical steganography, the project evaluates their effectiveness in securely transmitting and storing data. This has significant implications for data protection in cybersecurity, defense, and financial services, enhancing the security of information handling.
#5 - Interpreting the mechanism(s) of granular zircon formation
Leah Shteynman
Impact cratering creates micro- and nano-structures in minerals that make up target rocks. These structures can record information about the cratering event, including about its timing, peak pressures and temperatures, and post-cratering processes. This project explores shock metamorphic textures in the mineral zircon, one of the most important minerals in Earth's crust for geochemical investigations. Specifically, two microstructures related to impact cratering are targeted: (1) the high pressure polymorph reidite and (2) the granular neoblastic texture. We use SEM, TEM, and STEM techniques in order to elucidate their mechanism(s) of formation, which have implications for these microstructures' utility for tracking impact processes.
#6 - Crystallographic tilt in coherently strained InAsSbBi grown on (100) GaSb substrates offcut toward [011]
Marko Milosavljevic
This work examines the presence of epilayer tilt in coherently strained InAsSbBi epilayers grown on GaSb substrates that are (100) on-axis and (100) offcut 1° to [011] and (100) offcut 4° to [011]. The measurements are performed using x-ray diffraction, and consist of angle area maps in the [011] and [0-1-1] directions and coupled scans in the [011], [0-11], [01-1], and [0-1-1] directions. The sample cross-section consists of a 500 nm GaSb buffer, a 10 nm InAs/10 nm AlSb barrier, the InAsSbBi active region, and a terminating 10 nm AlSb/10 nm InAs barrier/cap layer. The lattice planes of strained epilayers grown on offcut substrates tilt relative to the substrate offcut plane to accommodate the in-surface biaxial-strain and the out-of-surface distortion. Under tensile strain the epilayers tilt in the [011] direction and under compressive strain the epilayers tilt in the opposite [0-1-1] direction. Because of the presence of crystallographic tilt, the InAsSbBi layers are examined using symmetric (400) X-ray diffraction scans and angle area maps. The out-of-plane distortion is determined from coupled scans in the [0-11] and [01-1] directions, which are orthogonal to the epilayer tilt. The tilt angle is proportional to tetragonal distortion and the tangent of the offcut angle. The crystallographic tilt and the out-of-plane distortion results in an InAsSbBi unit cell that is triclinic when the offcut is in the high symmetry [011] direction, rather than tetragonal for on-axis growth. In addition to the out-of-plane tilt that is clearly observable, the boundary conditions of coherently strained growth on a stepped surface indicate the presence of roughly the same in-plane tilt. At the step edge, coherent growth is constrained in two directions: 1) out-of-plane along the (011) step edge and 2) in-the-plane on the (100) terrace surface. Since the epilayer is constrained in two dimensions, it distorts both out-of-plane and in-plane with the distortion increasing as the growth progresses away from the corner of the step edge. This results in a triclinic unit cell that is tilted both out-of-plane and in-plane. Expressions are derived and compared with experiment for the InAsSbBi layer tilt angles, lattice constants, and angles of the triclinic unit cell.
#7 - Unsupervised Deep Video Denoiser: A Potential Key to Extracting Information from Monochromated EELS
Yifan Wang
The main factor limiting interpretation of electron energy-loss spectroscopic (EELS) dataset collected by scanning transmission electron microscopes (STEM) is the signal-to-noise ratio (SNR). One of the most effective approaches that can improve dose efficiency is denoising. We developed the unsupervised deep video denoiser (UDVD), which was successfully applied to low dose in situ TEM movies. Here, we appied the UDVD on EELS dataset, revealing information under heavy noise.
#8 - Multiple Dimensions of Stacking Defects in InSeI
Patrick Hays
InSeI is a quasi-1D layered semiconductor that possesses a direct band gap (Eg ≈ in its bulk form, which is retained down to the “single-chain” limit. The material is composed of alternating left- and right-handed chiral InSeI chains held together by vdW forces. InSeI is also stable under ambient conditions, making it an attractive alternative to the many organic chiral materials currently available for optoelectronic applications. However, the defect genome of InSeI has not been thoroughly studied. In this report, we investigate a unique form of stacking defect observed in InSeI using HAADF-STEM, which is deemed a “one-dimensional stacking fault”. Structure models were created and used to perform STEM simulations to better understand the nature of this defect. Furthermore, high-pressure high-temperature synthesis of InSeI was conducted inside a multi-anvil cell in an attempt to modify the global stacking order of InSeI chains. Efforts to understand the structural, optical, and electronic properties of the resulting phase of InSeI are detailed here and compared with those of the ambient pressure InSeI phase.
#9 - Enhancing Bone Repair and Restoration with Sol-Gel Derived Hydroxyapatite Next-Generation Conformal Implant Coatings for Regenerative Orthopaedic Non-Metallic Surgical Implants
Priyanka Jatindra Desai
Rigid metallic surgical hardware, a gold standard in bone fracture treatment for over a century, continues to burden the healthcare system with serious adverse events that include infection, pain, impingement, migration, and mechanical failure which significantly increase healthcare costs. With substantial progress in regenerative engineered biomaterials and tissue engineering methodologies, it may now be possible to develop tunable, non-metallic, internal fixation devices utilizing advanced biomaterial composite designs that can improve patient outcomes. This study reports on the synthesis and processing of a robust sol-gel derived hydroxyapatite (HA) conformal implant coatings for next generation bone fixation surgical hardware applications. Among the various sol-gel coating techniques, dip coating possesses several advantages. This includes its ability to produce highly uniform coatings, its versatility in coating substrates having net shaped complex geometries, ability to produce uniform coatings of single and multiple layers, inherent flexibility, simplicity, and cost-effectiveness. However, the formation of sol-gel derived high-quality HA coatings are influenced by multiple experimental factors, necessitating a multi-factorial design of experiment (DOE) approach. This includes the identification of key control factors and levels crucial for producing high-quality HA coatings. The DOE approach taken herein led to the establishment of optimum dip coating processing conditions to produce mechanically robust HA coatings for next-generation non-metallic orthopaedic implant applications.
#10 - Measuring the Optical Dielectric Function of 2D Janus TMD Monolayers
Blake Povilus
Janus transition metal dichalcogenide monolayers exhibit unique optoelectronic properties, resulting from their broken mirror symmetry and intrinsic out-of-plane dipole moments, which distinguish them from their conventional counterparts. Despite many valuable theoretical studies, experimental characterization of the optical dielectric function of Janus TMDs remains scarce. In this work, normal-incidence reflectance and Kramers-Kronig constrained analysis are used to experimentally determine the complex optical dielectric function of excitonic SeMoS and SeWS monolayers. These results reveal the presence of excitonic resonances, band nesting features, and notable spin-orbit coupling effects. Additionally, we investigate the change in the dielectric function across partially converted Janus samples, demonstrating further tunability in their optoelectronic properties. These findings provide a fundamental platform for understanding the optical response of Janus TMDs.
#11 - Structural and angle-resolved optical and vibrational properties of chiral trivial insulator InSeI
Melike Erdi
Chiral materials possess distinct structural and quantum properties, with InSeI emerging as a promising topologically trivial insulator. This study introduces a scalable Bridgman growth method to produce large, stable InSeI single crystals. It highlights the polarization-dependent optical and vibrational properties of InSeI chiral chains. Structural analysis confirms its chiral nature, while electron energy loss spectroscopy identifies a 2.08 eV bandgap. Angle-resolved Raman spectroscopy reveals five distinct vibrational regions, contributing to a deeper understanding of chiral material systems.
#12 - Open-Air Plasma for Scalable Solid-State Battery Fabrication and Advanced Materials Processing
Mohammed Sahal
Solid-state batteries (SSBs) go beyond the limits of lithium-ion batteries (LiBs), delivering nearly twice the energy density (~500 Wh·kg⁻¹, ~1200 Wh·L⁻¹), five times lower self-discharge (≪2–5% per month) for enhanced storage stability, and a lifespan exceeding 3000 cycles. Additionally, by eliminating toxic, flammable electrolytes and preventing thermal runaway, SSBs provide a safer and more reliable solution for energy storage.
However, unlike LiBs, where liquid electrolytes naturally ensure efficient contact with porous electrodes, SSBs require precise control of the electrode-electrolyte interface and densification for effective contact and ion transport. This introduces complexity in manufacturing, involving high-temperature sintering, pressure-assisted consolidation, moisture management, and thermal stabilization of electrodes and electrolytes.
Current SSB manufacturing techniques are limited in their ability to integrate these additional steps for efficient cost-effective large-scale in-line fabrication. They typically rely on: (i) prolonged vacuum-based hot pressing or sintering of brittle pellets, or (ii) costly, slow, and non-scalable vacuum-based deposition methods. In contrast, integrating slurry-based large-area thin-film deposition techniques, such as spin and blade coating, with open-air plasma processing for in-line high-temperature sintering and advanced moisture management offers a practical, scalable, and cost-effective solution to the challenges faced by existing methods.
In this study, we demonstrate that open-air plasma treatment (i) enhances interface resistance and electrode contact by reducing surface contamination (e.g., Li₂CO₃) in solid electrolyte LLZO, (ii) ultra-fast functionalization of slurry-deposited LLZO thin-film electrolytes, and (iii) high-temperature sintering of the solid electrolyte LiPON. These improvements are validated using advanced materials characterization techniques, including Raman Spectroscopy, X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM/EDS), and Powder X-ray Diffraction (XRD).
#13 - Sulfonated Metal-Organic Polyhedra as a Polysulfide Immobilizer in High-Performance Lithium/Sulfur Cell.
Soyeon Ko
A lithium/sulfur (Li/S) battery is one of the most promising next-generation rechargeable batteries due to its high theoretical specific energy (2600 Wh/kg vs. ~550 Wh/kg for conventional lithium-ion batteries). However, low electrical conductivity of sulfur and the problematic “lithium polysulfide (Li-PS) shuttle effect” occurring in the organic liquid electrolyte result in substantial performance degradation, preventing the commercialization of Li/S batteries. To tackle these challenges, earlier studies have focused on the modification of sulfur cathode by encapsulating elemental sulfur into nano-sized pores of porous carbon material. This approach aims to enhance the electronic conductivity of sulfur cathode and physically restrict the diffusion pathway of Li-PS. Although the performance of sulfur-porous carbon cathodes has been enhanced, there remains a need for further advancements to improve their electrochemical performance, specifically in enhancing the capture of Li-PS. This study aims to develop an innovative active material design which effectively mitigates the Li-PS shuttle effect by employing a multi-functional sulfonated metal-organic polyhedral (SMOP, [Cp3Zr3O(OH)3]4[BDC]6[(C2H5)2NH2]2Cl6]) that functions both as a sulfur confinement agent and a polysulfide immobilizer.[3] Mesoporous hallow carbon sphere (HCS) is chosen as the host material of the sulfur-HCS-MOP (S-HCS-SMOP) composite, which features a distinctive morphology and chemical structure, including elemental sulfur and SMOP nano-confined within HCS. SMOP has modified from the nano-sized discrete cage of Zr-based MOP, which is chemically stable material under electrochemical reaction, and successfully introduced to the S-HCS composite to prepare the S-HCS-SMOP. Consequently, the combination of carbon-host composite and nano-sized polysulfide immobilizer against the Li-PS shuttle is expected to enhance electrochemical performance of sulfur cathodes for Li/S batteries. These characteristics are thoroughly examined using advanced electron microscopy and spectroscopy techniques. The S-HCS-SMOP cathode successfully demonstrated improved capacity retention compared to both conventional S-porous carbon and S-HCS composite cathodes. Our results offer significant insights into the utilization of functionalized metal-organic materials for the development of high-performance lithium/sulfur cells, marking a notable contribution to the field.
#14 - Hydrogen Plasma Iron ore reduction study - A Decarbonization effort for the Steel Industry
Gabriela De Los Reyes Castillo
The iron and steel industry accounts for approximately 7% of global CO2 emissions. The ore reduction is traditionally carried out by a carbothermic multi-step process that generates CO2 as a byproduct, which contributes to global warming caused by greenhouse emissions and raises economic concerns. A more sustainable alternative is the implementation of Hydrogen Plasma to carry out the reduction process. Plasma is a state of matter where gas is ionized, creating a mix of positively and negatively charged electrons. Atomic, ionic, and vibrationally excited hydrogen species are present in this state, which can carry out the reduction efficiently and at low temperatures by creating localized heating, unlike the volumetric heating that is required with hydrogen in the molecular form. There are multiple reasons to use hydrogen plasma, as it offers both thermodynamic advantages and enhanced reaction kinetics, leading to a faster rate of the reduction compared to conventional methods. Additionally, it has environmental benefits, as the process produces H2O instead of CO2, eliminating harmful emissions and reducing the footprint of steel production. H2 Plasma reduction also eliminates the need for metallurgical coke and intermediate processing steps by switching to direct steelmaking, where liquid steel is obtained directly from the iron ore, bringing a reduction of energy consumption.
#15 - Stacking Monolayers of Transition Metal Dichalcogenides
Triston Vo
Artificially stacked layers of transition metal dichalcogenides (TMDs) have gained significant interest in recent years due to their unique correlated properties such as unconventional superconductivity, and topological effects which can be controlled by changing the relative lattice parameters and twist angle. Mechanical exfoliation allows clean, large monolayers that are free from defects to be isolated. There are many challenges when creating a twisted structure due to the difficulty of identifying monolayers, deterministically stacking them, controlling the twist angle, and understanding their structural orientation. In this poster we go through the process of creating twisted homo and hetero-bilayers. We utilize a matlab based GUI that plots the intensity profiles of the flakes and the substrate of an RGB image to identify the number of layers. Using a custom built “transfer” station that has precision controlled x-y-z-r manipulators,we are able to transfer the monolayers from a substrate onto a target substrate or a TEM grid with success. The rotation stage on this transfer station helps us to align the two different layers together. Aligning the samples to smaller twist angles (∼1°) can be achieved by techniques such as the tear and stack method and leveraging the way crystals fracture to our advantage. By utilizing these techniques, we have fabricated twisted homo and hetero-bilayers.
#16 Multiscale Analysis Of Defects For The Electrical Characterization Of AlGaN/GaN Heterostructure
Anacleto Proietti
Gallium Nitride (GaN) has emerged as a revolutionary semiconductor, enabling breakthroughs in high-frequency and high-power electronics. Its wide bandgap, high electron mobility, and strong breakdown field make it a critical material for applications demanding efficiency, speed, and thermal stability. GaN offers significant advantages for power electronics, 5G communication, and automotive systems, compared to silicon (Si) and silicon carbide (SiC). However, structural and electronic defects strongly affect the performance and reliability of AlGaN/GaN heterostructures. In this study, defects in an AlGaN/GaN heterostructure grown on SiC are analyzed using a multiscale characterization approach. Strain variations and defect-induced recombination are revealed by Raman spectroscopy and photoluminescence while Scanning Electron Microscopy identify hexagonal V-pits associated with threading dislocations and EDX confirms their deep penetration into the structure. Furthermore conductive atomic force microscopy (C-AFM) reveals leakage currents along the defect edges, and scalpel C-AFM reveals buried conductive dislocations suggesting a huge impact of these on the general electrical behaviour. Indeed, trapped charges and the 3D morphology of defects are further detected and imaged by scanning microwave impedance microscopy (sMIM). These results underscore the critical impact of defects on device performance and highlight the need for advanced nanoscale characterization to improve GaN-based electronics.
#17 Advance Packaging Defect Identification Through Correlative Microscopy And High-resolution SAM
Srijan Chakrabarti
The reliability and performance of advanced electronic packaging hinge on the precise identification of microscale defects. To have a well-rounded analysis of these defects we have presented a correlative workflow including White Light Interferometry (WLI), X-ray tomography (XRT), Small Angle X-ray Scattering (SAXS), X-ray Photoelectron Spectroscopy (XPS), and Plasma Focused Ion Beam (PFIB) analysis provide a holistic view of material integrity and defect characterization. This workflow complements a non-destructive metrology method called Scanning Acoustic Microscopy (SAM). For a more accurate experimental setup we have used a finite element method called CIVA which numerically solves ultrasonic wave interaction with materials and voids. The work we present here highlights key parameters such as frequency, probe depth, resolution, and working distance which require parametric optimization through CIVA. Preliminary results from A, B, and C scans from simulation reveal critical insights into wave propagation phenomena and the interaction of high-frequency acoustic waves with void defects. These findings not only validate the proposed correlative microscopy workflow but also underscore the potential of high-frequency SAM (ranging from 400 MHz to 1 GHz) as an indispensable tool for the non-destructive evaluation of advanced packaging. Future work will extend these studies with even higher frequency transducers to further refine the detection capabilities and simulation accuracy.
#18 Non-Perturbative Nanoscale Magnetic Sensing with Nitrogen-Vacancy (NV) Centers in Diamond
Sakib Ahmed
One of the interesting failure analysis techniques is to implement magnetic current imaging, requiring high spatial resolution with excellent magnetic field sensitivity. To ensure ultra-high spatial resolution and magnetic field sensitivity with non-perturbative approach, quantum sensing with nitrogen-vacancy (NV) centers in diamond has been proven to be a strong magnetic microscopy technique, known as Scanning Nitrogen-Vacancy Magnetometry (SNVM). Along with an optical confocal microscope and a microwave (MW) antenna, the NV center can be excited through green laser and the optical readout to evaluate external magnetic field. Recently, this configuration has been implemented to demonstrate non-perturbative probing of magnetic inhomogeneities in Ni and CoFeB nanowires with sensitivities down to a few µT.Hz-1/2. With the implementation of efficient laser and MW pulsing sequences it is possible to dramatically improve the sensitivity of magnetic field measurement.