Changes in the vacancy size distribution induced by non-bonded hydrogens in hydrogenated amorphous silicon

•The presence of large amounts of non-bonded hydrogens in a-Si:H resulted in changes in the vacancy size distribution.•The vacancy size distribution was determined using positron annihilation lifetime spectroscopy.

It was demonstrated that the presence of large amounts (≥ 2.8 at.%) of non-bonded hydrogens (NBHs) in hydrogenated amorphous silicon (a-Si:H) resulted in changes in the vacancy size distribution, where the vacancy size distribution was determined using positron annihilation lifetime spectroscopy. NBHs in small vacancies induced large nanovoids (>~1 nm), via the relaxation of internal stresses in the a-Si network, without decreasing the atomic number density of the silicon.