Doctoral Students
Hyeongjun (Jun) Koh
Email: hjkoh@seas.upenn.edu
Biography:
Jun received a Bachelor’s degree in 2016 and a Masters degree in 2018 in Chemical and Biomolecular Engineering from the Korean Advanced Institute of Science and Technology (KAIST). He is a Ph.D. candidate, having joined Penn in 2019. He was awarded the MSE Intel Graduate Award in 2023.
Research Interest:
Before coming to Penn, his research was focused on understanding the electrical behavior of Ti3C2Tx MXene films upon gas exposure, utilizing in-situ XRD. Presently, he is utilizing cryogenic TEM methods to characterize battery materials.
Cheng-Yu Chen
Email: cychen97@seas.upenn.edu
Biography:
Cheng-Yu received a Bachelor’s degree in in 2019 and a Master’s Degree in 2021 in Materials Science and Engineering at from the National Taiwan University. He joined the group at Penn in the Fall of 2022.
Research Interest:
During his Master’s studies, his research focused on reconstructing 3D microstructures by electron tomography using HAADF-STEM images. He will be researching the degradation processes of supported nanocatalyst systems through in-situ TEM imaging, combined with automated image analysis through machine learning methods.
Yihui Zhang
Email: yihuizh@seas.upenn.edu
Biography:
Yihui received a Bachelor’s degree in 2017 from Beijing Jiaotong University and a Master’s degree in 2019 in Materials Science and Engineering from University of California, San Diego. She joined the group at Penn in the Spring of 2023.
Research Interest:
Before moving to Stach’s group, her research was focused on understanding the SEI and morphology evolution of Li metal anode upon XPS and cryo-FIB during her Master. In Stach’s group, she is currently studying the interfaces of solid-state Li-metal batteries and other beam sensitive materials using Cryo-FIB/TOF-SIMS and Cryo-TEM.
Yinuo (Nelly) Zhang
Email: zhyinuo@seas.upenn.edu
Biography:
Yinuo received a Bachelor’s degree in 2021 from the Qingdao University of Science and Technology and received a Master’s degree in 2023 from the University of Pennsylvania. She joined the Stach’s group at Penn in the Summer of 2023 and is co-advised by Dr. Troy Olsson in ESE department.
Research Interest:
During her Master’s studies, her research focused on improving the ferroelectric switching performance of AlScN thin films by manipulating deposition gas flow. She will be researching the strategies to lower the coercive field and improve the endurance of AlScN memory devices as well as understanding the failure mechanism of thin film memory devices through electron microscopes.
Erika Ortega Ortiz
Email: eoo@seas.upenn.edu
Biography:
Erika joined the group in Fall of 2022, after receiving her Bachelors at Harvard University in the Spring of 2022.
Research Interest:
Prior to Penn, Erika focused on optimizing the growth of transparent conductive oxides through molecular beam epitaxy and sputtering, or a combination of both techniques, guided by analysis using XRD and AFM. At Penn, her current focus is on exploring the surface attachment of molecular catalysts using STEM.
Swarnendu Das
Email: sdas2001@seas.upenn.edu
Biography:
Swarnendu completed his Bachelors in Metallurgical Engineering from Indian Institute of Technology (BHU) Varanasi, India in 2023. He joined the Stach group at Penn in the Fall of 2023.
Research Interest:
Before joining Penn, Swarnendu focused on studying microstructural evolution and phase transformation in Inconel 625 produced by Laser Directed-Energy Deposition, by analysing XRD, SEM and TEM data.
George Hollyer
Email: ghollyer@seas.upenn.edu
Biography:
George received a bachelor’s degree in 2022 in Materials Science and Engineering from the University of Pennsylvania. Before joining the Stach group in the fall of 2023, he worked as a Research Engineer for Nelumbo Inc.
Research Interest:
During his bachelor’s degree, his research was in synthesis and STEM characterization of metallic core-shell nanoparticles for heterogenous catalysis. His current focus is on high-pressure in-situ TEM and machine learning for beam-sensitive materials as a Soft AE fellow.
