Photoluminescence studies of implantation damage centers in Si-30

We report photoluminescence (PL) studies of implant-damage centers in Si-30. The X and W zero-phonon lines (ZPLs) shift by +1.55(5) and +1.27(5) meV, respectively, between Si-nat and Si-30. Using a simple empirical approach, we calculate the shifts to within similar to20%. Local vibrational modes are identified at the X center and confirmed at the W center, supporting the assignment of these centers to self-interstitial clusters. All the strong PL lines produced by ion implantation in the sample have isotope shifts characteristic of ZPLs; they all correspond to independent defect centers, the majority of which have undetermined structures. (C) 2004 American Institute of Physics.