Anisotropy-induced optical transitions in PbSe and PbS spherical quantum dots

Optical-absorption spectra of PbSe and PbS spherical quantum dots have been studied both theoretically and experimentally. Exact theoretical analysis of the energy spectra and optical transitions has been carried out in the f ramework of four-band k.p-method with full account of the anisotropy effect s. It is demonstrated that strong anisotropy of the energy bands of bulk Pb Se and PbS results in pronounced optical transitions in quantum dots, which an forbidden in isotropic approximation. These anisotropy-induced transiti ons have been clearly observed in the measured absorption spectra of the Pb Se and PbS quantum dots.