Light absorption and photoluminescence in quantum dots and artificial molecules

Intraband absorption in n- and p-doped structures with InAs/GaAs quantum dots covered by InGaAs layers is studied both experimentally and theoretically. The absorption cross-sections for p-type quantum dots was found to be significantly smaller than for n-type quantum dots. Interband absorption bleaching under strong interband excitation is found and investigated in undoped quantum dot structures. Structures with artificial molecules were grown. Photoluminescence spectra and transmission electron microscopy images proves the presence of coupled symmetrical quantum dots. (author)