Imaging Ni segregation in synthetic diamond using ionoluminescence (IL) and particle induced X-ray emission (PIXE)

Ionoluminescence (IL) performed with a nuclear microprobe is potentially a highly sensitive method for measuring optically active impurities and defects in diamonds. In this study, a Sumitomo synthetic diamond sample grown in the presence of a Ni catalyst is imaged with IL and particle induced X-ray emission (PIXE). Ni impurities incorporated during the growth are identified with IL spectroscopy, and shown to segregate into [1 1 1] growth sectors with IL imaging. This finding is consistent with previously published luminescence results. PIXE analysis performed on the same regions of the sample confirm the presence of Ni. PIXE and IL analyses are compared and used to show that the improved sensitivity of IL over PIXE is ideal for imaging such optically active impurities in diamonds. (C) 2001 Elsevier Science B.V. All rights reserved.