$\mathrm{Ag}/6H-\mathrm{SiC}\mathrm{}\left(0001\right)\mathrm{}$ surface phase and its structural transformation upon exposure to atomic hydrogen

The surface phase of $\mathrm{Ag}/6H-\mathrm{SiC}\mathrm{}\left(0001\right)\mathrm{}$ and its structural transformation upon exposure to atomic hydrogen were investigated using scanning tunneling microscopy (STM). Ag deposition onto the $6H-\mathrm{SiC}\mathrm{}\left(0001\right)\mathrm{}\sqrt{3}\times \sqrt{3}$ surface at $500°\mathrm{C}$ resulted in the formation of a $3\times 3-\mathrm{Ag}$ structure that coexisted with a homogeneous two-dimensional (2D) Ag layer without showing any periodicities. The scanning tunneling spectroscopy spectrum of a 2D Ag layer exhibited metallic behavior. After atomic hydrogen exposure at $300°\mathrm{C},$ the 2D Ag layer changed into 3D Ag clusters, while the $3\times 3-\mathrm{Ag}$ area became disordered, exhibiting only a few Ag clusters. The $3\times 3-\mathrm{Ag}$ area and the 2D Ag layer were reproduced by annealing at $500°\mathrm{C}.$ This result is similar to atomic-hydrogen-induced self-organization processes on Si substrates covered with a monatomic metal layer.