Effect of dislocations on the photoluminescence decay of 1.54 mu m emission from erbium-doped silicon

The decay of the photoluminescence at 1.54 mum from erbium-implanted silico n has been recorded over nearly three decades of intensity. Two components of the decay are observed at 7.5 K, one with a decay time constant of simil ar to 40-160 mus, and the other with a characteristic time of between 800 a nd 1200 mus. It is found that the proportions of fast and slow components c an vary depending upon the amount of implantation-induced damage, and this variation correlates with a broadening on the high energy side of the erbiu m related emission. The temperature dependence of the fastest decay is not consistent with it being due to an Auger process involving free carriers, a nd it is suggested that extended defects in the layers are responsible for this part of the decay curve. The broadening of the erbium line is attribut ed to the overlap of the dislocation-related line D1 with the erbium emissi on. Selective chemical etching and scanning electron microscopy show that t here are extended defects present in samples with a short fast decay compon ent. (C) 2001 American Institute of Physics.