Laser-induced electronic bond breaking and desorption on Si(0 0 1)-(2×1)

Laser-induced structural changes and desorption have been studied for Si(0 0 1)-(2×1) at laser fluence below melt threshold. The excitation removes the Si dimer on this surface and induces monatomic-Si desorption, with the rate depending on the excitation intensity superlinearly. The excitation spectroscopy shows the enhancement of the rate at photon energies where optical transition injects holes into the surface occupied dimer back-bond band. The mechanism of the electronic desorption is discussed based on these results.