About

Jong Eun Ryu is an Associate Professor in the Department of Mechanical and Aerospace Engineering at NC State University, having joined the institution in 2018. He holds a Ph.D. in Mechanical Engineering from the University of California, Los Angeles, obtained in 2009, and both BS and MS degrees from KAIST in Korea, earned in 2004 and 2006 respectively. Prior to his appointment at NC State, Dr. Ryu was an assistant professor at Indiana University-Purdue University Indianapolis from 2013 to 2018, and he completed a two-year postdoctoral training at UCLA focusing on plasmonic sensors. His professional background also includes experience as a senior R&D engineer at Intel Corporation, working on advanced semiconductor lithography technology. Dr. Ryu's primary research interests involve leveraging artificial intelligence to revolutionize the design and optimization of multiphysics and multiscale systems. His work emphasizes the integration of digital simulations and models to develop robust solutions for real-world problems, including the implementation of digital twins for multiphysics systems to enable accurate predictions and informed decision-making. His research group explores multifunctional composites with applications in photoacoustics, optics, anti-biofouling, superhydrophobic surfaces, electromagnetic interference mitigation, flexible electronics, daytime radiative cooling, and photovoltaic panels. Additionally, his research extends to the 3D heterogeneous integration of electronics for high performance and reliability, the development of next-generation smart materials for ultrasound and piezoelectric applications, and in-situ resource utilization supporting space exploration efforts such as lunar and Mars manufacturing.

Research topics

• Materials science
• Composite material
• Nanotechnology
• Physics
• Chemical engineering
• Optoelectronics
• Optics
• Engineering
• Computer Science
• Physical chemistry
• Structural engineering
• Telecommunications
• Organic chemistry
• Electrical engineering
• Mechanical engineering
• Process engineering
• Chemistry
• Engineering physics

Selected publications

• A statistical approach to analyzing domain dynamics in ferroelectric crystals using X-ray photon correlation spectroscopy

  Acta Materialia · 2026-04-27

  articleOpen accessSenior authorCorresponding

  Ferroelectric materials exhibit strong electromechanical coupling, largely influenced by their domain structures. Numerous microstructural studies indicate that smaller domains with higher domain wall density generally enhance domain wall motion, although some inconsistencies have been reported. In this work, we use X-ray photon correlation spectroscopy (XPCS) to probe dynamic response in Pb(Mg 1/3 Nb 2/3 )O 3 -29PbTiO 3 (PMN-29PT) single crystals under applied electric fields. We introduce a two-field correlation approach, adapted from conventional two-time correlation to quantify dynamics. Statistical analysis reveals that both [001]-oriented direct current (DC) and alternating current (AC) poled samples show Poisson-like behavior within specific electric field regions. The DC-poled samples exhibit more frequent domain wall jump events but with smaller amount of decorrelation per jump event, whereas the AC-poled samples show fewer jump events with larger decorrelation per jump event. This observation aligns with the prevalence of 109° domain walls in the AC-poled samples, which contribute to more domain wall motion. These findings provide experimental evidence of collective domain wall motion and establish a direct connection between mesoscale dynamics and electromechanical response.

  PublisherDOI

• Flexoelectricity enables piezoelectric single crystals to be self-poled

  npj Flexible Electronics · 2026-04-09

  articleOpen access

  Piezoelectric materials used in transducer applications suffer from thermal depolarization, resulting in performance degradation or complete loss of their piezoelectricity. Self-poling is a promising phenomenon, as it enables ferroelectric materials to spontaneously develop net polarization and exhibit piezoelectric response without a conventional poling process. However, the mechanism of self-poling in bulk ferroelectric materials remains controversial and unclear. Here, we demonstrate that inhomogeneous physical properties in the bulk ferroelectric single crystals can induce flexoelectricity-driven unidirectional self-poling. We confirmed the presence of inhomogeneous lattice parameters, thermal expansion coefficients, and phase transition temperatures along the [001] direction in the Mn-doped 0.71Pb(Mg1/3Nb2/3)O3−0.29PbTiO3 single crystal through in-situ high-energy synchrotron radiation X-ray diffraction analysis. These inhomogeneities allow the single crystal to preserve its non-centrosymmetric state along the [001] direction well above TC and enable thermal activation of the self-poling even below TC. These self-poling ferroelectrics are expected to resolve critical reliability issues in future electronic applications.

  PublisherOA PDFDOI

• Thermal and Reliability-Oriented Structural Optimization of IMS Substrates for Power Module Applications

  2025-10-21

  article

  To address thermo-mechanical challenges in power module substrates, this study investigates three Insulated Metal Substrate (IMS) designs with varied copper layer thicknesses. Finite element analysis (FEA) was employed to predict thermal resistance and mechanical warpage, followed by experimental validation through warpage measurements and dielectric insulation tests. The objective is to identify an optimal IMS configuration that balances thermal performance with mechanical reliability, thereby providing a robust substrate solution for next-generation power electronics.

  PublisherDOI

• Experimental and numerical analysis of thermal performance and deformation in a lightweight composite bicycle brake disc

  Smart Science · 2025-11-21

  articleSenior author
  PublisherDOI

• Enhanced domain dynamics in alternating current poled rhombohedral Pb(Mg _1/3 Nb _2/3 )O ₃ –PbTiO ₃ single crystals

  Journal of the American Ceramic Society · 2025-04-30 · 5 citations

  articleOpen accessSenior authorCorresponding

  Abstract The understanding of domain dynamics in ferroelectric materials is crucial for optimizing their performance in piezoelectric and electro‐optic applications. Although previous studies have focused on static domain structures and macroscopic characteristics, the time‐resolved approach of domains remains largely unexplored. In this study, we compare the dynamic responses of direct current (DC) and alternating current (AC) poled [001]‐oriented rhombohedral Pb(Mg 1/3 Nb 2/3 )O 3 –PbTiO 3 (PMN–PT) single crystals using X‐ray photon correlation spectroscopy (XPCS) during the application of external electric fields. Our results demonstrate that the AC‐poled sample exhibit enhanced reconfiguration of domain variants in response to driving fields compared to the DC‐poled counterpart, as evidenced by accelerated correlation decay and faster relaxation time. This phenomenon is attributed to enhanced reversible domain wall motion achieved through AC poling, which facilitates field‐induced domain realignment. These findings provide insight into the relationship between dynamics and macroscopic properties in relaxor‐PT single crystals for high‐performance applications.

  PublisherOA PDFDOI

• Co-Design and ML-Based Optimization of Through-Via in Silicon and Glass Interposers for Electronic Packaging Applications

  IEEE Transactions on Components Packaging and Manufacturing Technology · 2025-01-08 · 16 citations

  articleSenior author

  Copper-filled via is a critical component of advanced electronic packaging technologies. Embedded in interposer substrate, vias provide enhanced electrical performance in 2.5D and 3D electronic packaging by allowing a smaller form factor. In addition to the electrical characteristics of an electronic package, its thermal and mechanical performance also depends on via geometry and the interposer material. This necessitates a co-design approach integrating thermal, mechanical, and electrical considerations. This paper focuses on a numerical parametric study and multi-objective machine learning-based optimization of through-silicon via (TSV) and through-glass via (TGV). This study investigates the multidisciplinary effects of aspect ratio (AR) and pitch in the square and hexagonal array vias. Copper protrusion, thermal resistance, and electrical parasitics were used as the optimization performance indicators. An online artificial neural network (ANN) algorithm, as well as the conventional genetic algorithm (GA), were adopted to optimize the through-via designs. The parametric study demonstrated that glass substrates are more effective in reducing copper protrusion and mutual capacitance up to 47.5% and 67.6% compared to silicon. However, TSVs showed superior thermal performance. A higher aspect ratio (AR) helps minimize the copper protrusion for mechanical performance. Moreover, the thermal performance was enhanced by reducing the pitch and using hexagonal array vias. Regarding electrical performance, a high pitch and low AR are preferable to minimize electrical parasitics. Finally, a 61.3% decrease in the computation time was achieved by using an online ANN-based optimization scheme compared to GA, highlighting its potential in the optimization of high-fidelity complex electronic designs.

  PublisherDOI

• Recent development in piezoelectric materials and devices for cryogenic environments

  Sensors and Actuators A Physical · 2025-02-14 · 12 citations

  article
  PublisherDOI

• Design, Fabrication, and Operation Challenges of Advanced Power Packaging Technology for EV Power Modules

  2025-04-08 · 2 citations

  article

  Double-sided cooled (DSC) power modules enable high power density for medium-voltage converter applications. Incorporating Wide Bandgap (WBG) devices, these modules reduce switching losses by effectively handling rapid switching transients. This work discusses the design, fabrication and operation challenges of a 400 V / 61 A Gallium Nitride High Electron Mobility Transistors (GaN HEMT) DSC epoxy resin Insulated Metal Substrate (eIMS) based power module, which integrates GaN devices, gate drivers, power decoupling, and gate bypass capacitors into a power-dense package. The discussion includes the electro-thermo-mechanical design steps, emphasizing achieving low parasitic inductances of 0.15 nH for the gate and 1.18 nH for the power loop and a high transient edge capability of 8.3 ns. The study also addresses the thermo-mechanical stress distribution reliability of the package, with different substrate dielectric materials, and verifies power cycling performance.

  PublisherDOI

• AI-Based Optimization of Co-Designed Stacked Metallized Substrate Module Structures

  2025-07-08 · 1 citations

  articleSenior author

  Silicon Carbide (SiC) power modules offer superior switching performance in medium and high voltage (MV and HV) applications but are prone to partial discharge (PD) due to high electric field concentrations. This paper focuses on techniques to mitigate electric field intensity, including stacked substrates, segregated copper pads, filled cavities, and protruded dielectrics, to enhance the PD performance of SiC power modules. A simulation-based co-design framework is introduced to incorporate both electric field and thermomechanical effects. Additionally, a non-dominated sorting genetic algorithm (NSGA) is employed to explore the trade-offs between PD mitigation and the die-attach solder fatigue life under power cycling. The optimization results indicate a 67.5% reduction in electric field intensity compared to conventional 10 kV designs, highlighting the effectiveness of the method in improving PD performance. Furthermore, a comparison of different substrate materials reveals that increasing the number of stacked layers significantly impacts the thermomechanical reliability of modules using epoxy resin composite dielectric (ERCD) and Al<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> substrates, whereas AlN-based modules are less affected.

  PublisherDOI

• Domain Switching Dynamics in [001]- and [111]-Poled Rhombohedral PMN-PT Single Crystals Through X-Ray Photon Correlation Spectroscopy

  2025-07-13

  articleSenior author

  Relaxor-<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{PbTiO}_{3}$</tex> single crystals are distinguished by remarkable electromechanical properties, making them valuable for applications in ultrasound transducers. Although many studies have explained the high performance of these materials, real-time observation of dynamics remains challenging. In this study, we investigate correlation dynamics in <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Pb}\left(\text{Mg}_{1 / 3} \text{Nb}_{2 / 3}\right) \mathrm{O}_{3}-\text{PbTiO}_{3}(\text{PMN}-\text{PT})$</tex> rhombohedral single crystals using X-ray photon correlation spectroscopy (XPCS). Two crystal orientations, [111] and [001], are examined under bipolar electric field to understand their polarization switching behavior. The correlation decay patterns are analyzed using the Kohlrausch-Williams-Watts (KWW) model, providing quantitative insights into the rate of nucleation and growth. XPCS measurements reveal significantly shorter relaxation times in the [001]-poled sample compared to the [111]-poled counterpart. This enhanced dynamics in the [001]-poled specimen correlates with superior permittivity and piezoelectric coefficient (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$d_{33}$</tex>), which indicates enhanced domain wall motion as interpreted through classical nucleation and growth mechanisms.

  PublisherDOI

Recent grants

• Investigation of the ferroelectric domain dynamics and its effects on macroscopic behaviors using a synchrotron X-ray photon correlation spectroscopy

  NSF · $180k · 2023–2025

• Collaborative Research: Template-Free Manufacturing of Regular Microstructures by Ribbing-Enhanced Roll Coating

  NSF · $675k · 2020–2024

Frequent coauthors

• Zhanhu Guo

  University of Adelaide

  106 shared

• Evan K. Wujcik

  University of Maine

  52 shared

• Jiahua Zhu

  Nanjing Tech University

  41 shared

• Suying Wei

  Lamar University

  40 shared

• David P. Young

  Louisiana State University

  38 shared

• Vignesh Murugadoss

  Central Glass and Ceramic Research Institute

  37 shared

• Bin Wang

  36 shared

• Subramania Angaiah

  Pondicherry University

  36 shared