Influence of Growth Break before Capping on Photoluminescence Dynamics of CdSe/ZnSe Self-Assembled Quantum Dots

Abstract

Influence of growth breaks before capping of CdSe self-assembled quantum dot layers on photoluminescence dynamics was examined in three samples. Short (5 s) break resulted only in a small blue shift, caused probably by partial strain relaxation and/or Zn interdiffusion. Long (20 min) break induced a strong broadening and red shift of the spectra, combined with a dramatic slow down of the photoluminescence decays. The main result of the long break was identified as introduction of defects (impurities), which generate local electric fields and act as traps of photogenerated carriers.