The origin of the 0.78 eV luminescence band in dislocated silicon

We report the results of a study into the influence of implanted impurities on luminescence in the region of the well-known D1 luminescence band that is associated with dislocations in silicon. A photoluminescence band at around 0.78 eV, which is sometimes seen in silicon containing a high density of dislocations, has been attributed to the presence of oxygen complexes. In this study we have deposited layers of Si 0.9 Ge 0.1 onto single-crystal Si substrates by MBE in order to induce dislocations in the silicon substrate. The samples have subsequently been implanted with iron, erbium or oxygen in order to study the effect of implanted impurities on D-band photoluminescence at around 800 meV. Following implantation with oxygen, two luminescence bands appear at around 0.85 and 0.78 eV, respectively. These bands are not present in either the unimplanted sample or those subject to Er or Fe implantation. The correlation between oxygen doping and the appearance of these bands supports the conjecture that they are associated with oxygen complexes.