EFFECTS OF BAND NONPARABOLICITY AND CENTRAL-CELL CORRECTIONS ON THE SPECTRUM OF SI DONORS IN GAAS QUANTUM-WELLS

Data on donor magneto-optical 1s --> 2p + 1 transitions in four center -doped GaAs/AlxGa1-xAs quantum wells ranging in width from 10 to 52 nm is presented and analyzed for magnetic fields between 0 and 6 T. It i s found that both band nonparabolicity and central-cell corrections mu st be considered in the narrower wells in order to obtain satisfactory agreement with experiment. A theory of band nonparabolicity is introd uced which includes important terms arising from the donor Coulomb pot ential, terms previously ignored in the analysis of quantum-well donor spectra. In the narrower wells relatively large central-cell correcti ons are calculated for Si donors from bulk data. A central-cell correc tion of approximately 0.75 cm-1 is estimated for bulk Si donors at zer o magnetic field from analysis of published data on Si-doped GaAs epit axial films.