Spectroscopic studies of excitonic fine structure under electric fields

The application of an external electric field to GaAs/Ga1-xAlxAs quantum wells has allowed us to resolved the 2p excited state of the heavy-hole exciton. A sharing of the oscillator strength between this excited state and the ground state of the light-hole exciton, together with an anticrossing behavior, has been observed in low-temperature photoluminescence excitation spectra. A rare structure for well thickness {greater-than or approximate} 120 A ̊, in the energy range of the forbidden exciton associated with the first conduction subband and the second heavy-hole subband, has been attributed to valence-band mixing between the first light-hole and the second heavy-hole subbands. © 1987.