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…
131. Robust Excitonic-Insulating States in Cu-Substituted Ta2NiSe5
Author
Junseong Song, Eilho Jung, Byeong Wook Cho, Bumsub Song, Jae Woo Kim, Hyeonbeom Kim, Ki Kang Kim, Byoungchul Son, Jouhahn Lee, Jungseek Hwang*, Young Hee Lee*
Journal
Advanced Materials Interfaces
Publication Date
2023.03.27
Project Number
IBS-R011-D1
Abstract
Excitonic insulators exhibit intriguing quantum phases that further attract numerous interests in engineering the electrical and optical properties of Ta2NiSe5. However, tuning the electronic properties such as spin-orbit coupling strength and orbital repulsion via pressure in Ta2NiSe5 are always accompanied with electron-hole pair breaking, which is a bottleneck for further applications. Here, the robust excitonic-insulating states invariant with electron-doping concentrations in Ta2NiSe5 are demonstrated. The electron doping is conducted by substituting Cu into Ni site (Ta2Ni1-xCuxSe5). The majority carrier of pristine sample is a hole-type and is converted to electron-type with a doping concentration over x = 0.01, whose carrier density can be controlled by varying the Cu concentration. The excitonic transition temperature (Tc) does not significantly alter with electron-doping concentrations, which is stark contrast with the declining Tc as the hole-type dopant of Fe or Co increases. The optical conductivity data also demonstrate the invariant excitonic-insulating states in Cu-doped Ta2NiSe5. The findings of invariant excitonic-insulating states in n-type Cu-substituted Ta2NiSe5 can be utilized for further electronic device applications by using excitons.