The spectrally resolved FWM signal of CdSe quantum dots with sizes below the bulk excitonic Bohr radius has been studied as a function of temperature and excitation intensity and compared with bulk CdSe. A clear oscillation with a period of 163fs (approximate to 25 meV) is found in the transient FWM signal and attributed to a coherent coupling of confined electron-hole pairs with LO-phonons. Two side bands are observed in the spectrum 25 meV below and above the excitonic resonance. The strong coupling to LO-phonons is observed even at excitation densities around 1 x 10(16) cm(-3) which is close to the bulk value of the Mott density.
|Journal||IPPS physica status solidi (b)|
|Publication status||Published - 1997|