Figure 6
STM images of a Ge QD dense array at different phases of its evolution from patched WL to 2D nanocrystalline layer: T gr = 360°C, h Ge = a 4.4 Å, before nucleation (see also Figure 3 for details of array nucleation at h Ge = 5.1 Å); b 6 Å, growing small huts, nucleation goes on; c 8 Å, maximum density (~6 × 1011 cm-2); d 10 Å, maximum uniformity, large huts start to coalesce; e, f 14 Å, huts go on coalescing; g 15 Å, 2D layer starts to form; h, i, j, k 18 Å, 2D nanocrystallyne film grows, chaos of faceted hillocks and pits (i) is observed; however, Ge WL (M × N)-patched structure is clearly resolved on bottom of pits (j, k).