The Process of Dispersing Bismuth Atoms into Iridium via an Intermediate Monolayer of Graphite

Abstract

It is first revealed by thermodesorption spectroscopy that when bismuth atoms diffuse the indium atoms through an intermediate graphite layer, they show certain characteristic features. In the Ir (111)-C system at 1400 K < T < 1600 K, we witness the most strong form of diffusion of bismuth into iridium. It has been found that the fractions of the fluxes of intercalation equal to δ = 0.4 ± 0.05 and diffusion δ Bi = N dif / N = 2.5 × 10 -3 bismuth atoms in the Ir(111)-C system. The amount of intercalated and diffused bismuth depends on the electrical field, i.e., on the positive potential in the Ir(111)-C system. It has been noted that a considerable diffusion of bismuth into iridium started at 180 V and increased up to 3000 V. The activation energies for bismuth diffusion into and from iridium were calculated to be E n 1 = 6.05 ± 0.05 eV and E 1 n = 6.3 ± 0.1 eV, respectively.