Characterization of liquid targets in Vacuum condition

Yamamoto, Kazami; Ogiwara, Norio*; Kuramochi, Masaya*

e-Journal of Surface Science and Nanotechnology (Internet), 21(4), p.359 - 364, 2023/07

https://doi.org/10.1380/ejssnt.2023-053

In recent years, durable target is required according to increase of the beam power. To solve this problem, a liquid film was formed in vacuum and tested it as a target. An ethanol and a mercury were selected as liquid target materials, and we investigated whether the liquid sheet could be formed stably in a vacuum and how about the vacuum pressure. As a result, it was confirmed that the liquid films were stably formed in both case and the pressures with the films were about the vapor pressure of the materials.

Band hybridization between graphene and Hex-Au(001) reconstructed surface

Terasawa, Tomoo; Matsunaga, Kazuya*; Hayashi, Naoki*; Ito, Takahiro*; Tanaka, Shinichiro*; Yasuda, Satoshi; Asaoka, Hidehito

no journal, , 

As a Hex-Au(001) surface shows one-dimensional corrugation and is chemically inert, it has been employed to study the effect of one-dimensional potential on graphene. Such potential has been expected to make the band structure of graphene anisotropic, which shows the mini-gap at the zone boundary across the potential and the high group velocity along the potential. However, the bandgap in the graphene on Hex-Au(001) was only indirectly suggested by scanning tunneling spectroscopy. Here, we report the band structure of graphene on Hex-Au(001) substrates using angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT) calculation. The ARPES image shows the bandgap in the graphene band close to the Au 6sp band. The DFT calculated band structure shows the bandgap not at the crossing point of the graphene bands but that of graphene and Au 6sp bands. We thus conclude that the bandgap originates from the hybridization between graphene and Au. This hybridization is similar to that observed in the graphene and Au interface on the SiC substrate. We expect that the hybridization between graphene and Au is essential as the Rashba splitting of 100 meV was observed around the gap.

Graphene nanoribbon synthesis from well-ordered DBBA monolayer

Yano, Masahiro; Yasuda, Satoshi; Asaoka, Hidehito

no journal, , 

Rotational-energy transfer of hydrogen molecule on solid surface

Ueta, Hirokazu; Fukutani, Katsuyuki

no journal, , 

Atomic arrangements of graphene quasicrystal

Fukaya, Yuki; Zhao, Y.*; Kim, H.-W.*; Ahn, J.-R.*; Fukidome, Hirokazu*; Matsuda, Iwao*

no journal, , 

no abstracts in English

Hydrogen isotope separation by tunneling effect used graphene-based heterogeneous electrocatalysts in electrochemical hydrogen pumping

Yasuda, Satoshi; Matsushima, Hisayoshi*; Terasawa, Tomoo; Yano, Masahiro; Asaoka, Hidehito; Gueriba, J.*; Dio, W.*; Fukutani, Katsuyuki

no journal, , 

We fabricated heterogeneous electrode with layered structures consisting of palladium and graphene layers and reported D2 enrichment from hydrogen and deuterium mixture gas using polymer electrolyte membrane electrochemical hydrogen pumping used the fabricated electrode. Mass spectroscopic analysis demonstrated significant bias voltage dependence of hydrogen/deuterium (H/D) separation ability and the H/D value decreases as the bias voltage increases. Theoretical analysis showed that the observed high H/D at low bias voltage stems from hydrogen isotopes tunneling through atomically-thick graphene during the electrochemical reaction, and the bias dependent H/D results in a transition from the quantum tunneling regime to classical over- barrier regime for hydrogen isotopes transfer via the graphene. These findings provide new insight for a novel economical methodology of efficient hydrogen isotope enrichment.

Role of molecularly-adsorbed O on oxidation at SiO/Si(001) interface

Tsuda, Yasutaka; Yoshigoe, Akitaka; Ogawa, Shuichi*; Sakamoto, Tetsuya*; Takakuwa, Yuji

no journal, ,