Scanning tunnelling microscopy revealed significant structural modifications that involved atom desorption and displacement following light irradiation with 0.09 to 2keV electrons. In the case of (111)-(7 x 7), the adatom-layer vacancies increased monotonically in number with incident energy. In the case of (100)-(2 x 1), the irradiation produced dimer vacancies and ad-dimers as Si atoms transferred to the terrace. The modification processes were linked to the energy distribution of electron-hole and electron attachment states that resulted from inelastic cascade scattering. Beams which were previously believed to be benign therefore introduced structural surface modifications.

Electron-stimulated modification of Si Surfaces K.Nakayama, J.H.Weaver: Physical Review Letters, 1999, 82[5], 980-3