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Volume 5, Issue 3 (Suppl) Mod Chem Appl, an open access journal
ISSN: 2329-6798 Global Chemistry 2017
September 04-06, 2017
September 04-06, 2017 | London, UK
5th Global Chemistry Congress
Electronic and magnetic behaviors of 2D atom-thin layers: Graphene, black phosphorus, hexagonal boron-
nitride and MoS2
Junji Haruyama1, 2
1Aoyama Gakuin University, Japan
2University of Tokyo, Japan
Two-dimensional (2D) atom-thin layers have attracted significant attention after the discovery of primitive fabrication method
of graphene (i.e., mechanical exfoliation of graphite using scotch tapes). As a van-deer Waals engineering, various atom-thin
layers and those hybridization are recently studied. In the talk, first, I present magnetism and spintronics arising from edges of
2D atom-thin layers (e.g., graphene, few-layer black phosphorus (BP), hexagonal boron-nitride (hBN), and molybdenum disulfide
(MoS2)). I create nanomesh (NM) structures, consisting of honeycomb like array of hexagonal nano-pores, with specified pore-
edge atomic structure (i.e., zigzag type) on individual layers. Interestingly, hydrogen-terminated graphene NM (H-GNM) shows
flat-band ferromagnetism, while it disappears in oxygen-terminated GNM (O-GNM). On the other hand, O-BPNM exhibits large
ferromagnetism (100 times) due to ferromagnetic spin coupling of edge O-P bonds, whereas it is eliminated in H-BPNM. O-hBNNM
also shows large ferromagnetism due to edge O-B and O-N bonds, while it disappears in H-hBNNM. These are also highly sensitive
to annealing temperatures to form zigzag pore edge. These open a considerable avenue for realizing 2D atom-thin flexible magnetic
and spintronic devices, fabricated without using rare-earth magnetic atoms. Second, I show creation of the world-thinnest Schottky
junction on few-layer MoS2, one of the transition metal dichalcogenides. The 2H-phase of MoS2 has direct band gaps of 1.5−1.8 eV.
It is demonstrated that electron-beam (EB) irradiation to the 2H-phase causes semiconductor-metal transition to 1T-phase and
atomically-thin Schottky junction with barrier height of 0.13−0.18 eV is created at the interface of 2H/1T regions. These findings also
indicate a possibility that the effective barrier height is highly sensitive to electrostatic charge doping and almost free from Fermi-level
pinning when assuming predominance of the thermionic current contribution. This EB top-down patterning opens the possibility to
fabricate in-plane lateral heterostructure FETs, which have shown promising scaling prospects in the nanometer range, and/or local
interconnects directly with metallic phase (1T) between (2H)MoS2 transistors, resulting in ultimate flexible and wearable in-plane
integration circuits without using 3D metal wirings. Finally, I will also briefly talk about introduction of spin-orbit interaction into
graphene by nano-particle decoration.
Biography
Junji Haruyama graduated from Waseda University, Tokyo, Japan, in 1985. He joined Quantum Device Laboratory, NEC Corporation, Japan and worked until 1994.
He received PhD in Physics from Waseda University in 1996. During 1995–1997, he worked with the University of Toronto, Canada and also Ontario Laser and
Lightwave Research Center (Canada) as a Visiting Scientist. Since 1997, he has been working at Aoyama Gakuin University as a Professor. He was also a Visiting
Professor at NTT Basic Research Laboratories, Institute for Solid State Physics, University of Tokyo, and Zero-emission Energy Center, Kyoto University, Japan.
He has been also a Principal Researcher at Air-Force Office of Scientific Research (AFOSR), USA, since 2010. He has peer review publications over 100 and four
patents, and also invited talks over 150.
Junji Haruyama, Mod Chem Appl 2017, 5:3(Suppl)
DOI: 10.4172/2329-6798-C1-005