Copyright 2004 by Marcel Dekker, Inc. All Rights Reserved.

Figure 8 Photoluminescence spectra at 10 K for InP QDs with a mean diameter of32 A˚ for different excitation energies. The first exciton peak in absorption is at 2.17 eV.Curve f is the global PL because all sizes in the QD ensemble are excited; curves a–erepresent FLN spectra arising from size-selective excitation in the red tail of theabsorption spectrum. (From Ref. 10.)spectrum is then obtained with excitation at the first peak of the PLEspectrum. The energy difference between the first FLN peak and the firstPLE peak is then defined as the resonant red shift for the ensemble of QDsrepresented by the selected PLE energy. This process is repeated across the redtail of the absorption onset region of the absorption spectrum to generate theresonant red shift as a function of QD size. Typical FLN and PLE spectra areshown in Fig. 9 for InP QDs with a mean diameter of 32 A˚ . The resultant T =11 K resonant red shift as a function of PL excitation energy ranges from 6 to16 meV [10]. Theoretical modeling of this resonant red shift in InP QDs isbased on the effects of electron-hole exchange in splitting the lowest-energyexcitonic transition into singlelike and triplelike states and is described inRefs. 49 and 50.Copyright 2004 by Marcel Dekker, Inc. All Rights Reserved.