A phosphate glass embedded with PbSe semiconductor quantum dots (QDs) has b
een synthesized and investigated. Optical absorption spectra of PbSe spheri
cal QDs have been studied both theoretically and experimentally. Theoretica
l analysis of the energy spectra and optical transitions has been carried o
ut in the framework of four-band k.p model taking full account of anisotrop
y effects. It is demonstrated that the strong anisotropy of the energy band
s of bulk PbSe gives rise to additional optical transitions in the quantum
dots. These anisotropy-induced optical transitions have been clearly observ
ed in the measured absorption spectra of the PbSe quantum dots. The calcula
ted energy positions of the optical transitions are in good agreement with
experiment. Five optical transitions were distinguished and interpreted in
the absorption spectra measured at T = 12 K. For the set of samples with a
narrow size distribution of PbSe QDs (diameters in range of 40-110 Angstrom
), the energies of three or four optical transitions have been determined f
rom the measured absorption spectra at T = 300 K. The calculated dependenci
es of the energies of the first five optical transitions with QD size are i
n good agreement with those obtained from the experimental data. (C) 2000 A
merican Institute of Physics. [S0021-8979(00)07814-2].