세종대학교 물리학과
세종대학교 물리학과
학과소개 학과소개 새소식 학사정보 연구실/사람들 동문마당 게시판/자료실


2016.10.26
[콜로퀴움] Environment-Dependent Electrical Properties of Monolayer MoS2

‧제목  Environment-Dependent Electrical Properties of Monolayer MoS2
‧연사  한국표준과학연구원/과학기술연합대학원대학교(UST) 김용성 교수님
‧일시  2016년 10월 26일 (수요일) 오후 5시
‧장소  영실관 613호

초 록

Two-dimensional (2D) semiconductors are manifested themselves by strong Coulomb interactions therein between charges. Whatever the charges are, the strong Coulomb interactions give remarkable effects on the semiconductor properties; e.g. (i) large exciton binding energy (electron-hole), (ii) large quasi-particle self-energy (electron-electron), (iii) large scattering cross section in carrier transport by charged defects (electron-charged defects), (iv) deep defect transition level (bound electron-charged defects), and (v) strong interactions between charged defects (charged defects-charged defects) [1]. The Coulomb interactions can be effectively screened by dielectric environments surrounding the 2D semiconductors, by which the electrical optical properties of the 2D semiconductors can be strongly affected. We investigate the electronic bandgap and electrical doping properties of monolayer MoS2 with a variety of dielectric environments using density-functional-theory(DFT) and GW calculations. We show that the quasiparticle bandgap changes drastically with the dielectrics [2] and the dopant transition levels show deep-to-shallow level transitions by the environmental dielectric screening effect [3,4].

[1] Ji-Young Noh, Hanchul Kim, and Yong-Sung Kim, Phys. Rev. B 89, 205417 (2014).
[2] Junga Ryou, Yong-Sung Kim, Santosh KC, and Kyeongjae Cho, Scientific Reports 6, 29184 (2016).
[3] Nguyen T. Son, Yong-Sung Kim, and Erik Janzen, Phys. Status Solidi RRL 9, 707 (2015).
[4] Ji-Young Noh, Hanchul Kim, Minkyu Park, and Yong-Sung Kim, Phys. Rev. B 92, 115431 (2015).  





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