LEED study of Ni (1 0 0) and (1 1 1) surface damage caused by Ar‘ ion bombardment with low energy and small doses

Abstract

Surface damage formation on the Ni (1 0 0) and Ni (1 1 1) surfaces induced by Ar‘ ion bombardment at low energy (0.1}1.2 keV) and small doses ((5]1015 ion/cm2) was studied with LEED. The degradation of the di!raction spot intensities was measured directly during ion bombardment. Using the procedure of Jacobson and Wehner for description of the exponential intensity/dose function, the mean area of damage per incident ion was determined. The experimental results have con"rmed that partial annealing of the surface damage takes place at room temperature during ion bombardment. An exponential relationship observed between point defect concentration and annealing time at higher temperature indicated a "rst- order reaction. The activation energies for Ni (1 0 0) and Ni (1 1 1) surfaces were determined. ( 2000 Elsevier Science Ltd. All rights reserved.