Growth of monoatomic layer terraces on a (111) lead crystal face: In situ observations in dark field by UHV-TEM

The growth of (111) lead tabular crystals obtained by vapour deposition onto a cleaved surface of graphite has been observed using an ultra high vacuum transmission electron microscope (UHV-TEM). Monoatomic terraces are observed in dark field where the nucleation site of the terraces seems to be due to dislocations emergent at the surface. The growth of a terrace follows three stages: (i) nucleation and isotropic lateral extension until it reaches one side of the tabular crystal (ii) preferential lateral growth of the terrace along the edge of the crystal, (iii) fill up the hole formed at the end of the previous stage.