Luminescence of strained Si1−xGex alloy layers grown by molecular beam epitaxy

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Abstract
Thick Si1−xGex strained layers grown by molecular beam epitaxy on Si(100) oriented substrates are investigated by photoluminescence spectroscopy. Well resolved near‐band‐gap luminescence is clearly observed in samples with a Ge concentration ranging from 10% to 20% for both as‐grown and thermal annealed samples. The phonon assisted transitions are clearly identified and the phonon structure of the spectrum is resolved. The effects of deuterium passivation and rapid thermal annealing are studied and an enhancement of the intrinsic excitonic luminescence by more than a factor of three is observed upon deuteration. These results indicate that atomic deuterium is efficient in passivating nonradiative recombination centers responsible for the quenching of the band edge luminescence. The exciton energy band gap is shown to have a quasilinear dependence with Ge fraction between 9% and 26%.