Intraband transitions in semiconductor nanocrystals

Intraband spectra of CdSe nanocrystal colloids are observed. The photoexcited nanocrystals, of average diameters 31.5, 38, and 43 Angstrom, exhibit an isolated and strong infrared-induced absorption with peak energy between 0.5 and 0.3 eV. The energies and cross sections of the resonance are consistent with a one-electron transition between the delocalized 1 S-e and 1 P-e states of the strongly confined quantum dots. (C) 1998 American Institute of Physics.