Carrier relaxation and quantum decoherence of excited states in self-assembled quantum dots - art. no. 241303

We report systematic measurements of photoluminescence excitation spectra a nd dephasing times (T-2's) on various excited states of hundreds of individ ual quantum dots (QDs). From the variation of T-2's with the energy separat ion between excited states and the ground state (E-rel), we identified two distinct regions of E-rel where LO phonon emission and hole relaxation via LA phonon emission play as dominat dephasing mechanisms. We also found a cl ear evidence of significantly slow energy relaxation in the E-rel range whe re these phonon emission processes are suppressed due to the reduction of i nteraction phase space.