Scanning tunneling microscopy investigation at high temperatures of islands and holes on Si(1 1 1)7×7 in real time: evidence for diffusion-limited decay

The annealing behavior of hole- and island-like nanostructures fabricated in situ in the scanning tunneling microscope on Si(1 1 1)7×7 has been investigated in the range from 720 to 830 K. In contrast to previous work, the analysis reveals diffusion-controlled decay kinetics to be described by a (t0−t)2/3 law. From the temperature dependence of the diffusion coefficient, we obtain an activation energy of (1.49±0.12) eV which is discussed in terms of a diffusion barrier for the moving adatoms. The comparison of the decay between hole and island structures suggest a missing Ehrlich–Schwoebel barrier for hole filling.