size with typical areas of $A \sim 25 \times 70$ nm$^2$.

In all islands an underlying area of higher contrast is observed, which is bordered by the outer clusters of the islands. Using EDX-detection no elements except for Au and C are found in these islands. The binary alloy phase diagram of Au and C excludes the formation of Au-C alloys under the given conditions[@McLe69] and we conclude that the C signature stems from the substrate. The analysis given in Secs. \[sectionFilmChar\], \[sectionThick\], and \[sectionTemp\] consistently suggest that the islands are formed of 4 to 8 monolayers of Au on top of the substrate. This conclusion is supported by the MC simulations of the formation process of such an Au film in Sec. \[sectionMCfilm\].

HRTEM images of the islands as depicted in Fig. \[expfig1\](c) show regions, in which crystalline patterns occur with lattice spacings determined as 501 pm and 310 pm within an estimated error of $\pm
5$%. The angles between these two spacings differ up to 6$^\circ$ from a rectangular configuration. It cannot be excluded that much larger areas of the Au films are crystallized forming such patterns because a slight corrugation of the substrate may obscure its detection 