Correlation between photoluminescence and infrared absorption spectra of oxidized nanoscale silicon clusters

We report in situ photoluminescence and ex situ Fourier transform infrared spectra of nanoscale silicon clusters exposed to atomic hydrogen, molecular oxygen, and humidified argon. Comparisons between infrared absorption spectra of fresh and aged samples indicate that photoluminescence efficiency is correlated with a stoichiometric oxide shell and the presence of Si dangling bond passivants at the core/oxide interface. Photoluminescence quenching is demonstrated in efficiently luminescing samples upon exposure to atomic hydrogen with recovery of photoluminescence occurring upon subsequent exposure to air. The photoluminescence quenching and recovery is correlated with a partial quenching and recovery of absorption due to interfacial silane groups. The correlations between photoluminescence and infrared absorption spectra, together with the hydrogen quenching results, provide evidence that radiative recombination in these samples is associated with interfacial oxide-related defects.