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.
Papers
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Journal ArticleDOI
Defects activated photoluminescence in two-dimensional semiconductors: interplay between bound, charged, and free excitons
Sefaattin Tongay,Joonki Suh,Joonki Suh,Can Ataca,Wen Fan,A. V. Luce,A. V. Luce,Jeong Seuk Kang,Jonathan Liu,Changhyun Ko,Rajamani Raghunathanan,Jian Zhou,Frank Ogletree,Jingbo Li,Jeffrey C. Grossman,Junqiao Wu,Junqiao Wu,Junqiao Wu +17 more
TL;DR: This work investigates effects of anion vacancies in monolayer transition metal dichalcogenides as two-dimensional (2D) semiconductors where the vacancies density is controlled by α-particle irradiation or thermal-annealing and finds a new, sub-bandgap emission peak as well as increase in overall photoluminescence intensity as a result of the vacancy generation.
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Monolayer behaviour in bulk ReS2 due to electronic and vibrational decoupling
Sefaattin Tongay,Sefaattin Tongay,Hasan Sahin,Changhyun Ko,A. V. Luce,Wen Fan,Wen Fan,Kai Liu,Jian Zhou,Jian Zhou,Ying-Sheng Huang,Ching-Hwa Ho,Jinyuan Yan,D. Frank Ogletree,Shaul Aloni,Jie Ji,Shu-Shen Li,Jingbo Li,François M. Peeters,Junqiao Wu,Junqiao Wu,Junqiao Wu +21 more
TL;DR: A new member of the family ofemiconducting transition metal dichalcogenides, rhenium disulphide (ReS2), where such variation is absent and bulk behaves as electronically and vibrationally decoupled monolayers stacked together.
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Oxide Electronics Utilizing Ultrafast Metal-Insulator Transitions
TL;DR: In this paper, the authors discuss the role of materials synthesis in influencing functional properties and discuss future research directions that may be worth consideration, concluding with a brief discussion on future directions that are worth consideration.
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Doping against the native propensity of MoS2: degenerate hole doping by cation substitution.
Joonki Suh,Tae Eon Park,Der Yuh Lin,Deyi Fu,Joonsuk Park,Hee Joon Jung,Yabin Chen,Changhyun Ko,Chaun Jang,Yinghui Sun,Robert Sinclair,Joonyeon Chang,Sefaattin Tongay,Junqiao Wu,Junqiao Wu +14 more
TL;DR: Stable p-type conduction in MoS2 is demonstrated by substitutional niobium (Nb) doping, leading to a degenerate hole density of ∼ 3 × 10(19) cm(-3), and it is expected that the synthesis technique demonstrated here can be generally extended to other TMDs for doping against their native unipolar propensity.
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Anisotropic in-plane thermal conductivity of black phosphorus nanoribbons at temperatures higher than 100 K
Sangwook Lee,Fan Yang,Joonki Suh,Sijie Yang,Yeonbae Lee,Guo Li,Hwan Sung Choe,Aslihan Suslu,Yabin Chen,Changhyun Ko,Joonsuk Park,Kai Liu,Kai Liu,Jingbo Li,Kedar Hippalgaonkar,Jeffrey J. Urban,Sefaattin Tongay,Junqiao Wu,Junqiao Wu +18 more
TL;DR: Large anisotropy in in-plane thermal conductivity of single-crystal black phosphorus nanoribbons along the zigzag and armchair lattice directions at variable temperatures is reported.