Radioactive Isotope Identifications of Au and Pt Photoluminescence Centres in Silicon

Abstract

Photoluminescence (PL) measurements on silicon samples implanted with radioactive Hg isotopes which decay fully or partly through the series Au/Pt/Ir are reported. Results obtained with 193Au isotopes (half-life 17 h) confirm earlier work concerning the involvement of Au in the 735 meV centre first observed in Fe-diffused silicon. A PL spectrum consisting of a series of doublets originating at 780/782 meV is found to be Au-related. An important new result is that the 1066 meV trigonal centre, commonly attributed to Fe–B pairs, is found to involve Au atoms. For Pt-related centres, 191Pt isotopes (half-life 2.9 days) provide conclusive proof of Pt involvement in three PL centres with zero-phonon lines at 1026, 884 and 777 meV. There is not sufficient evidence from the changes observed in the spectra to make any conclusive deductions concerning the occurrence of Ir-related PL spectra in our samples.