Room temperature sub-bandgap photoluminescence from silicon containing oxide precipitates

Room temperature photoluminescence was measured from p-type Czochralski silicon processed to contain oxide precipitates. No detectable luminescence was associated with unstrained oxide precipitates. Strained oxide precipitates gave rise to a broad luminescence peak centred at ∼1600 nm. The intensity of the peak increased with the density of strained precipitates, with band-to-band luminescence being reduced correspondingly. Dislocations and stacking faults around the strained precipitates were found to introduce competing non-radiative recombination centres which reduced the sub-bandgap photoluminescence. A mechanism is proposed for the sub-bandgap luminescence due to strained precipitates in terms of a transition between defect bands. © 2012 American Institute of Physics