Electroreflectance measurements have been carried out in order to investigate Stark-ladder transitions in a GaAs (40 AA)/AlGaAs (20 AA) superlattice under various uniform electric fields, and compared with the transition energies calculated on the basis of a microscopic tight-binding theory. The observed electroreflectance spectra over a wide range of photon energies (1.5-2.2 eV) shift in proportion to an applied electric field. The signals in a higher photon energy region (1.4-2.2 eV) indicate the existence of a transition from the spin-orbit split-off band in the valence band to the Wannier-Stark localization states in the conduction band. The assignment is supported by the tight-binding calculation. Resonant coupling between the localized states is also observed.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry