Quantum confinement by an order-disorder boundary in nanocrystalline silicon.

We predict theoretically and show experimentally the occurrence of quantum confinement in hydrogenated nanocrystalline silicon. We prove that only valence states (positively charged carriers) are confined effectively within the nanograins. The emission associated to confined states is verified by photoluminescence experiments on nanocrystalline samples with controlled grain size. According to the present study, we propose nanocrystalline silicon as a promising material for oxygen-free optoelectronics, silicon-based memories and photovoltaics.