Extended structural defects and their influence on the electroluminescence in efficient Si light-emitting diodes

We report our results on electroluminescence (EL) in the range of 1.0-1.6 mum, structural defects and electrophysical properties of light-emitting diodes fabricated by implantation of B and P ions into Si substrates with a subsequent thermal annealing at 700-1200degreesC in argon. A band-to-band emission peak dominates in the EL spectra of all the samples at 80-500 K. The internal quantum efficiency of the band-to-band EL, eta(int), and the minority carrier lifetime, tau(p), increase with annealing temperature to 1100degreesC, with the efficiency practically proportional to the lifetime. The maximum eta(int) was registered after annealing at 1100degreesC, when there are no extended structural defects. Rod-like defects, partial Frank and perfect prismatic dislocation loops are formed after annealing at lower temperatures. No correlation between the quantum efficiency and the defect structure was revealed with the variation of the annealing temperature. An increase of the value tau(p)/eta(int), proportional to the radiative. lifetime, with an increasing temperature has been observed. (C) 2003 Elsevier B.V. All rights reserved.