“…It was inferred that the electronic excitations and ionizations play practically no role in the recrystallization process Williams et al, 1985). In other experiments, in which a-Si layers were irradiated by the electron-beam, the recrystallization was observed only for energies above a threshold for atomic displacement of ~ 150 keV while below this threshold no epitaxial regrowth was produced, even after irradiation at very high electron doses (Lulli et al, 1987;Miyao et al, 1986;Washburn et al, 1983). Therefore, the observed epitaxy is associated with elastic collisions that transfer sufficient momentum to displace target atoms from their lattice site.…”