Novel Nano material Research group

Publication

Journals

  • Single-crystal growth
  • Wafer-scale single-crystal hexagonal boron nitride film via self-collimated grain formation
  • Joo Song Lee, Soo Ho Choi, Seok Joon Yun, Yong In Kim, Stephen Boandoh, Ji-Hoon Park, Bong Gyu Shin, Hayoung Ko, Seung Hee Lee, Young-Min Kim, Young Hee Lee, Ki Kang Kim, and Soo Min Kim. Science 362, 817-821 2018
  • We discover a method of synthesizing wafer-scale single-crystal (SC) hexagonal boron nitride (hBN) monolayer film. In contrary to traditional epitaxial growth, liquid gold substrate allows the self-collimation of circular hBN grains, eventually forming an SC hBN film on a wafer scale. SC hBN serves the growth template for SC-Graphene/hBN heterostructure and SC tungsten disulfide. This is the first…
  • 2D alloy
  • Tailoring Domain Morphology in Monolayer NbSe2 and WxNb1-xSe2 Heterostructure
  • ACS Nano 14, 8784-8792 2020
  • 2D material properties, including electronic and optical properties, can be adjusted through alloying. In this work, we dope NbSe2 with W to make a lateral heterostructure with semiconducting WSe2 on the inside and metallic NbSe2 on the outside. The each point of doping level is characterized by STEM (Scanning Transmission Electron Microscopy) and well correlated with optical (Raman, Photoluminesc…
  • Catalyst
  • Substitutional VSn Nanodispersed in MoS2 Film for Pt-scalable Catalyst
  • Frederick Osei-Tutu Agyapong-Fordjour, Seok Joon Yun, Hyung-Jin Kim, Wooseon Choi, Soo Ho Choi, Laud Anim Adofo, Stephen Boandoh, Yong In Kim, Soo Min Kim, Young-Min Kim, Young Hee Lee, Young-Kyu Han, and Ki Kang Kim. arXiv:2010.10908 2020
  • This work demonstrate the basal plane activation of 2D MoS2 via substituted V atoms as VSn unit in 2H-MoS2 lattice. The VSn units acts as acive sites and also charge transfer pathways for efficient hydrogen evolution.
  • Device application
  • Synthesis of hexagonal boron nitride heterostructures for 2D van der Waals electronics
  • Ki Kang Kim, Hyun Seok Lee, and Young Hee Lee. Chem. Soc. Rev. 47, 6342-6369 2018
  • This work reviews the recent progress of the large-area synthesis of hBN and other related vdW heterostructures via CVD, and artificial construction of vdW heterostructures and 2D vdW electronics based on hBN, in terms of charge fluctuations, passivation, gate dielectrics, tunneling, Coulombic interactions, and contact resistantces. The challenges and future perspectives for practical applications…
Switching polariton screening in MoS2 microcavity toward polaritonics
Author
Ashok Mondal, Chanda Biswas, Pramod Ghising, Byoung Hee Moon, Ki Kang Kim, Young Hee Lee
Journal
Science Advances
Despite the known behaviors of exciton-polariton in van der Waals transition metal dichalcogenides (TMDs),
achieving electrical control over these polaritons remains a challenge, particularly for manipulating multiple polariton states and further tuning polariton screening in polaritonics. Here, we identify various polariton states via
electrical bias within a monolayer of n-type MoS2. The MoS2 channel was squeezed within a distributed Bragg reflector microcavity which was combined with a transparent graphene gate-electrode and a hexagonal boron nitride insulator. We observe trion polaritons with distinct lower polariton branch (LPB) and upper polariton branch
(UPB). This allows us to modulate the intensity and energy switchings via gate bias: At gate bias below threshold
voltage, both polaritons are decoupled, and above threshold voltage, they are coupled to form LPB-UPB pair, and
at high bias, complex polaritons (CPB) emerge due to polariton screening, a phenomenon consistent with Rabi
splitting. Further, we observe a peculiar nonlinearity at intermediate power regime.