Quantum confinement regime in silicon nanocrystals

We study the origin of photoluminescence (PL) in Si nanocrystals embedded in a silicon-rich SiO2 matrix. PL properties as a function of time and temperature were investigated for nanocrystal diameters (d) ranging from about 1.5 to 4 nm. All our observations (logarithmic evolution of the timescale as a function of energy, gap associated temperature shift of the PL energy, and logarithmic evolution of size as a function of confinement energy) indicates that PL occurring in small nanocrystals (d<4 nm) originates from quantum confinement. (c) 2008 Elsevier B.V. All rights reserved.