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

Abstract
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.