Line broadening and localization mechanisms in CdSe/ZnSe quantum dots

We analyze the line-broadening mechanisms of single CdSe quantum dot (QD) e mission lines. A jitter in the emission energy of individual CdSe QDs is re ported for the first time. The jitter is caused by the quantum-confined Sta rk effect induced by the randomly fluctuating charges of defects in the vic inity of the QDs. These random processes lead to a broadening of the emissi on lines and usually inhibit the determination of a true homogeneous line w idth. On the other hand, identical jitter allows the unambiguous assignment of groups of emission lines to single QDs. A strong thermal broadening of the QD emission lines is observed. From our observations, parameters of the phase relaxation due to acoustic and LO phonon scattering, which is the ma in line broadening mechanism, are derived. (C) 2000 Elsevier Science B.V. A ll rights reserved.