Quantum confinement effect in crystalline silicon quantum dots in silicon nitride grown using SiH₄ and NH₃

Crystalline silicon quantum dots (Si QDs) were spontaneously grown in the silicon nitride films by plasma-enhanced chemical vapor deposition using SiH₄ and NH₃ as precursors. When the size of the Si QDs was reduced from 4.9 to 2.9 nm, the photoluminescence peak energy was shifted from 1.73 to 2.77 eV. The photoluminescence peak energy was fitted to the relationship, E(eV)=1.13+13.9 d², where d is the diameter of the Si QD in nanometers. The measured band-gap energies of the Si QDs were in good agreement with the quantum confinement model for crystalline Si QDs. These results suggest that the hydrogen dissociated from NH₃ plays an important role in improving the crystallinity and surface passivation of Si QDs.