Excitation-induced atomic desorption and structural instability of III-V compound semiconductor surfaces

We discuss the laser-induced structural instability of III-V compound semiconductor surfaces. The electronic instability is characterized by local bond rupture of both metallic and nonmetallic atoms at intrinsic surface sites, with the bond-rupture rate super linearly dependent on the excitation density. Spectroscopic studies show that bulk-valence excitation triggers surface bond rupture, and that valence holes are the responsible species. From our results, we propose a mechanistic model based on the two-hole localization induced by a high density of non-equilibrated valence holes, and demonstrate that the model describes all the important features quantitatively and consistently. Additional evidence that further supports the validity of the two-hole mechanism is presented.