Ultrafast carrier dynamics of Si quantum dots embedded in SiN matrix

Femtosecond spectrally resolved two-color three-pulse nonlinear spectroscopy is used to study the dynamics and coherence properties of excited carriers in Si quantum dot structures embedded in silicon nitride. A very short dephasing time of <180 fs at room temperature is observed. Ultrashort population relaxation times of ~400 fs and 6–10 ps are measured and discussed in the context of the different contributions from transverse optical and transverse acoustic phonon-assisted transitions.