MICROSCOPIC PHOTOLUMINESCENCE SPECTROSCOPY OF SELF-ORGANIZED CDSE-ZNSE QUANTUM DOTS GROWN ON THE GAAS(110) CLEAVED SURFACE

Self-organized CdSe/ZnSe quantum dots (QD's) were fabricated on the cl eavage-induced GaAs (110) surface in ultra high vacuum (UHV) by molecu lar beam epitaxy (MBE). CdSe layer showed the Stranski-Krastanow (S-K) growth mode. QW's and QD's emissions originated from the wetting laye r and island structures, respectively, were observed in photoluminesce nce (PL) spectra. This is a evidence of S-K type where island structur es are self-formed on the two-dimensional wetting layer as a result of the transition of the growth mode. The state filling effect in the QD 's was also observed by employing excitation power dependence on the P L intensity. By using the microscopic PL spectroscopy, the broad PL pe ak of QD's was resolved into a number of sharp peaks. These peaks are attributed to the recombination of excitons localized at the individua l QD's indicating that the fabricated CdSe islands have quasi-zero-dim ensional delta-function like density of states.