Le Journal de Physique IV 03 (1993) C5-233-C5-236
Space charge effects on interband optical nonlinearities in asymmetric coupled quantum wellsK. FRÖJDH1, U. OLIN2 and R. PLANEL3
1 Department of Physics II, 100 44 Stockholm, Sweden
2 Institute of Optical Research, 100 44 Stockholm, Sweden
3 Laboratoire de Microstructures et de Microélectronique, CNRS, 196 avenue Henri Ravera, BP. 107, 92225 Bagneux cedex, France
We have studied space-charge-induced optical nonlinearities for asymmetric coupled quantum wells. By the spatial separation of heavy holes and electrons, an electrostatic potential is induced which increases the fundamental bandgap. Calculations, using the Hartree approximation, for optimized AlGaAs structures show that a blue-shift of the band gap of 9 meV at a carrier density of 1012 cm-2 can be obtained. Experimental comparisons with a rectangular well show a large increase in room-temperature nonlinearities.
© EDP Sciences 1993