Centers & Labs

RIKEN Center for Emergent Matter Science

Quantum Effect Device Research Team

Team Leader: Koji Ishibashi (D.Eng.)
Koji  Ishibashi(D.Eng.)

To explore future nanoelectronics, we develop fabrication processes of sub-10 nm structures, and study their electroical and optical properties to apply them to functional nanodevices. We use carbon nanotubes, semiconductor (Ge/Si, InAs, InSb et al.) nanowires, graphene and functional molecules as building blocks of those nanostructures. Besides, we are interested in organic optical devices combined with plasmonic structures . With a combination of the top-down and bottom-up technologies, we fabricate quantum dots, CNT/molecule heterostructures and semiconductor/superconductor hybrid nanostructures for use in single electron devices and quantum computing devices.

Main Research Field

Complex systems

Related Research Fields

Mathematical and physical sciences / Engineering


  • Quantum devices
  • Nanostructures
  • Nanofabrication

Selected Publications

  1. Russell S. Deacon, Jonas Wiedenmann, Erwann Bocquillon, Teun M. Klapwijk, Philipp Leubner, Christoph Brüne, Seigo Tarucha, Koji Ishibashi, Hartmut Buhmann, Laurens W. Molenkamp,
    "Josephson radiation from gapless Andreev bound states in HgTe-based topological junctions",
    Phys. Rev. X 7, 021011 (2017)
  2. Hiroshi Tomizawa, Katsuya Suzuki, Tomohiro Yamaguchi, Seiji Akita and Koji Ishibashi,
    "Control of tunnel barriers in multi-wall carbon nanotubes using focused ion beam irradiation",
    Nanotechnology, 28, 165302 (2017)
  3. Erwann Bocquillon, Russell S. Deacon, Jonas Wiedenmann, Philipp Leubner, Teun M. Klapwijk, Christoph Brüne, Koji Ishibashi, H. Buhmann, Laurens W. Molenkamp,
    "Gapless Andreev bound states in the quantum spin Hall insulator HgTe",
    Nature Nanotechnology, 12, 137 (2017)
  4. Akira Hida, Takayuki Suzuki, and Koji Ishibashi,
    "Detecting the formation of single-walled carbon nanotube rings by photoabsorption spectroscopy",
    Appl. Phys. Express 9, 085102 (2016)
  5. Rui Wang, Russell S. Deacon, Diana Car, Erik P. A. M. Bakkers, and Koji Ishibashi
    "InSb nanowire double quantum dots coupled to a superconducting microwave cavity",
    Appl. Phys. Lett. 108, 203502 (2016)
  6. Akira Hida and Koji Ishibashi.:
    "Molecule-induced quantum confinement in single-walled carbon nanotube"
    Appl. Phys. Express 8, 045101 (2015)
  7. Xin Zhou and Koji Ishibashi.:
    "Single charge detection in capacitively coupled integrated single electron transistors based on single-walled carbon nanotubes"
    Appl. Phys. Lett. 101, 123506 (2012)
  8. T. Nishio, T. Kozakai, S. Amaha, M. Larsson, H. Nilsson, H. Q. Xu, G. Q. Zhang, K. Tateno, H. Takayanagi and K. Ishibashi.:
    "Supercurrent through InAs nanowires with highly transparent superconducting contacts"
    Nanotechnology, 22, 445701 (2011)

Lab Members

Principal Investigator

Koji Ishibashi
Team Leader

Core Members

Keiji Ono
Senior Research Scientist
Russell Stewart Deacon
Senior Research Scientist
Hui Wang
Postdoctoral Researcher