Development of low energy H gun for evaluation of H permeability of graphene

Terasawa, Tomoo   ; Fukutani, Katsuyuki; Yasuda, Satoshi   ; Asaoka, Hidehito  

Graphene, a single-layer honeycomb lattice composed of C atoms, is impermeable against gas molecules and ions. On the other hand, the permeation of hydrogen ions (H, including proton, deuteron, and triton) and the isotope effect for this phenomenon have been reported. However, the H permeability of graphene has been evaluated in water and H transport membranes. Thus the elementary process of the H permeation through graphene has not been revealed yet. The H permeability of graphene can be directly evaluated by H irradiation against graphene and ion current measurement after the permeation of graphene in a vacuum. Since the energy barrier of approximately 1 eV was reported for the H permeation, the energy resolution for H irradiation is required to be less than 1 eV. Here we employ the electrostatic hemispherical monochromator to the H ion gun to achieve the energy resolution less than 1 eV. We will discuss the separation of H ions and the energy resolution of the H ion beam at the presentation.