Formation of metallic nanoislands in the process of electron irradiation of a thin gold film on glass

It has been demonstrated experimentally that the local irradiation of a thin gold film on glass with electrons with an energy of 5 keV led to an increase in the thickness of the irradiated area. When the film was subjected to local irradiation with electrons with an energy of 25 keV, the irradiated region became thinner and a gold ring was formed along the perimeter of this region. At high densities of the electron current, thickened regions of the film assumed the shape of fractal nanostructures. The observed effects were induced by the formation of a negative charge region on the surface of glass (or in the bulk of it) and the migration of positive gold ions into this region.