OBSERVATION OF THE WANNIER-STARK LADDERS ASSOCIATED TO THE LIGHT-HOLEGROUND-STATE AND TO THE HEAVY-HOLE FIRST EXCITED-STATE IN GAINAS ALGAINAS SUPERLATTICES/

Photoluminescence excitation experiments have been performed with a no n-intentionally doped GaInAs/AlGaInAs superlattice lattice-matched to an InP substrate. The superlattice is the intrinsic part of a p-i-n di ode. We have observed the 1s and 2s heavy-hole exciton states and the Wannier-Stark ladder associated to the light-hole exciton. Three other lines in our spectrum are related to the Wannier-Stark ladder associa ted to the first excited state of the heavy hole. These transitions ar e weakly allowed from the built-in voltage existing in the superlattic e. Calculations based on Airy functions quantitatively support our int erpretation.