Field-induced decoupling of quantized levels and blue shift of absorption edge in a potential inserted quantum well structure

The electric field induced localization and decoupling of quantized levels (FILD) in double quantum wells is studied both theoretically and experimentally and is shown to result in a novel blue shift of optical absorption peaks. The absorption edge of doubly coupled 54 Å GaAs wells separated by a 5.7 Å AlAs inserted barrier is found to shift by 8 meV toward the higher energy under a moderate field (>30 kV/cm). Considering the field-induced variation of quantized levels and excitonic effect, the observed shifts of most peaks are well explained by the simple effective mass theory. Device applications of this novel electro-optic effect (FILD) are also discussed.