Effect of hydrogenation on the luminescence of strained Si1−xGex alloy layers grown by molecular beam epitaxy

Thick Si1−xGex strained alloy layers grown by molecular beam epitaxy (MBE) are investigated using photoluminescence (PL) spectroscopy. Near-band-edge luminescence with well resolved phonon structures is observed for both as-grown and deuterated samples. The low energy broad band frequently encountered in MBE-grown alloy layers is shown to be annihilated by deuteration, giving rise to the no-phonon and phonon-assisted near-band-edge PL peaks. The broad band recovers by annealing at T≥360 °C while the intensity of the near-band-edge luminescence vanishes. Secondary ion mass spectroscopy and the effect of deuterium passivation are used to help locate and assign the defects responsible for the low PL efficiency of MBE-grown thick SiGe layers.