The Use of Leed for the Characterization of Surface Damage from Pulsed Laser Irradiation

Abstract

Low Energy Electron Diffraction (LEED)-Spot Profile Analysis and AugerElectron Spectroscopy (AES) have been used to study the response of Mo(100) single crystal surfaces to Q-switched, frequency doubled Nd:YAG laser pulses. The experiments were conducted in a special ultra-high vacuum (UHV) system which allowed the surfaces to be irradiated under controlled conditions. Laser fluences both above and below the melt threshold were employed.For the melted surfaces, good epitaxial regrowth was observed.The spot profile analysis indicates the formation of random islands on the surfaces. Surfaces which had been previously disordered by 3 KeY Ar+ implantation were laser surface melted and observed to regrow epitaxially as has been observed in the case of ion implanted silicon.The formation of the islands and stepped structures is explained by considering the activation of dislocation sources by the induced thermal stresses resulting in slip.