Time‐resolved measurements of dislocation‐related photoluminescence bands in silicon

Abstract

Dislocation related luminescence (DRL) in Si was analyzed using time‐resolved techniques. A set of samples exhibiting different spectral features in the range of the D1 band was prepared by plastic deformation and subsequent thermal treatment. For all samples the sequence of time constants texc < tD4 < tD1 < tD2 has been observed where texc, tD4, tD1, and tD2 denote the time decay constants for the TO phonon replica of the Si bound exciton (TO BE) and D4, D1, and D2 DRL bands, respectively. It should be noted that the relation between decay times of the D1 and D2 bands remained same for all sub‐bands in the D1 family. Our results imply that transitions of similar nature are responsible for the bands. On the other hand, the lack of correlation between D1/D2 decay times and contamination levels suggests that intrinsic properties of dislocations are responsible for the corresponding transitions. We analyzed this observation in comparison with previous results and propose a model of recombination between two shallow and one deep level for D1/D2 bands. Differences in decay times are attributed to different spatial separation of shallow traps from a common deep trap. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)