The primary objective of our research group is to advance atomic-scale engineering capabilities in both materials and devices. We achieve this by exploiting operando transmission electron microscopy (TEM), integrating state-of-the-art atomic resolution TEM techniques with modern semiconductor device fabrication and precise electrical measurements. Our research emphasizes a comprehensive understanding and control of material properties and device functionalities at the atomic scale. By leveraging atomic-scale structural and chemical characterization along with precision fabrication techniques, we aim to develop novel materials and devices with unprecedented performance. This research drives innovation at the intersection of materials science and device engineering, leading to technological breakthroughs and a deeper understanding of material behavior at its most fundamental level.
We engineer novel designer interface by assembling various 2-D van der Waals building block crystals. By creating moiré superlattice and engineering the atomic scale reconstruction, we seek to investigate the emergent phenomena that exhibit quantum electronic behavior.
#van der Waals (vdW) materials #atomic scale engineering #moiré superlattice
*K. Ko et al. Nat. Mater. 22, 992 (2023);* *J. Kim et al. Nat. Mater. 21, 890 (2022);* *S. Sung et al. Nat. Commun. 13, 7826 (2022);* *X. Liu et al. Nature 583, 221 (2020); J. Sung et al. Nat. Nanotechnol. 15, 750 (2020); H. Yoo et al. Nat. Mater. 12, 448 (2019); S.S. Sunku et al. Science 362, 1153 (2018);*
Our group employs transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) to investigate the structures of materials from microscale down to the very atomic scale. Understanding the electron optics inside the microscopy and electron diffraction in crystals is key to investigate the structures of condensed matter. We study the atomic structure to understand the underlying materials properties and functionalities.
#transmission electron microscopy (TEM) #scanning transmission electron microscopy (STEM) #electron diffraction #image reconstruction #materials function
*K. Ko et al. Nat. Mater. 22, 992 (2023); H. Yoo et al. Nat. Mater. 12, 448 (2019); H. Yoo et al. Appl. Phys. Lett. 112, 131901 (2018); H. Yoo et al. Appl. Phys. Lett. 102, 051908 (2013); H. Yoo et al. Adv. Mater. 24, 515 (2012)*
Our group develops a new platform that enables the simultaneous operation of electronic devices and transmission electron microscopy (TEM) investigations. By applying modern semiconductor device fabrication techniques onto ultra-thin membrane structures, we create an operando TEM platform. This platform allows us to manipulate the material functions in an electrical device form and monitor structural dynamics with unprecedented temporal resolution.
[Operando TEM method]
