C
Changhyun Ko
Researcher at Sookmyung Women's University
Publications - 86
Citations - 8116
Changhyun Ko is an academic researcher from Sookmyung Women's University. The author has contributed to research in topics: Thin film & Phase transition. The author has an hindex of 33, co-authored 78 publications receiving 6698 citations. Previous affiliations of Changhyun Ko include Harvard University & University of California, Berkeley.
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Terahertz spectroscopy studies on epitaxial vanadium dioxide thin films across the metal-insulator transition
TL;DR: Results on terahertz (THz) spectroscopy on epitaxial vanadium dioxide (VO(2)) films grown on sapphire across the metal-insulator transition demonstrate an 85% reduction in transmission as the thin film completes its phase transition to the conducting phase, which is much greater than the previous observation.
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Pressure-induced phase transitions and metallization in VO 2
Ligang Bai,Quan Li,Serena A. Corr,Yue Meng,Changyong Park,Stanislav V. Sinogeikin,Changhyun Ko,Junqiao Wu,Guoyin Shen +8 more
TL;DR: In this paper, the results of pressure-induced phase transitions and metallization were reported based on synchrotron x-ray diffraction, electrical resistivity, and Raman spectroscopy.
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Ultrasensitive photodetectors exploiting electrostatic trapping and percolation transport.
Yingjie Zhang,Yingjie Zhang,Daniel J. Hellebusch,Daniel J. Hellebusch,Noah D. Bronstein,Noah D. Bronstein,Changhyun Ko,D. Frank Ogletree,Miquel Salmeron,Miquel Salmeron,A. Paul Alivisatos +10 more
TL;DR: A new photoactive material that reduces recombination by physically separating hole and electron charge carriers is developed, which enables an unprecedented photoconductive gain of 1010 e− per photon, and allows for effective control of the device response speed by active carrier quenching.
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Pressure-Temperature Phase Diagram of Vanadium Dioxide.
Yabin Chen,Shuai Zhang,Feng Ke,Changhyun Ko,Sangwook Lee,Kai Liu,Bin Chen,Joel W. Ager,Raymond Jeanloz,Volker Eyert,Junqiao Wu +10 more
TL;DR: This work maps out the hydrostatic pressure-temperature phase diagram of vanadium dioxide nanobeams by independently varying pressure and temperature with a diamond anvil cell to delineate their phase boundaries as well as reveal some basic features of the transitions.
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Studies on electric triggering of the metal-insulator transition in VO 2 thin films between 77 K and 300 K
TL;DR: In this paper, the authors investigate the electrically triggered metal-insulator transition (E-MIT) in VO2 thin films at temperatures far below the structural phase transition temperature (∼340 K).