Photoluminescence techniques were used to study the effect of low-temperature pre-annealing upon the intermixing of 3nm Si0.7Ge0.3/Si quantum wells which had been implanted with Si ions with energies of up to 1MeV and then exposed to rapid thermal annealing (850C, 300s). It was found that an unwanted quantum-well band-gap increase which occurred in non-implanted samples after rapid thermal annealing could be reduced from about 0.030 to about 0.005eV by the removal of grown-in defects during pre-annealing (630C, 24h). Pre-annealed samples that had been implanted and rapidly annealed exhibited at least the same band-gap increase (up to 0.07eV) that was observed in non pre-annealed samples. The results were explained in terms of the existence of significantly different activation energies for defect diffusion and quantum well intermixing, and a non-linear dependence of the energy shifts upon the defect concentration.

D.Labrie, G.C.Aers, H.Lafontaine, R.L.Williams, S.Charbonneau, R.D.Goldberg, I.V.Mitchell: Applied Physics Letters, 1996, 69[25], 3866-8