BIEXCITON FORMATION IN CDXZN1-XSE ZNSE QUANTUM-DOT AND QUANTUM-WELL STRUCTURES/

The dimensionality dependence of the biexciton formation process is in vestigated by comparing (Cd,Zn)Se/ZnSe quantum-dot and quantum-well st ructures using time-resolved photoluminescence (PL) spectroscopy. Mode ling the onset of the biexciton PL signal with a system of rate equati ons, we obtain a biexciton formation coefficient of about 4 x 10(-10) cm(2)/ps for 35-nm quantum dots and of 0.2 x 10(-10) cm(2)/ps for the quantum-well reference, respectively, indicating a distinct enhancemen t of the biexciton formation efficiency in quantum dots. By analyzing the spectral line shape of the PL signal, an increase of the biexciton binding energy from 6.4 meV in the case of the quantum-well reference , to 11.3 meV for the quantum dots. is determined.