A VARIATIONAL CALCULATION OF LIGHT-HOLE ENVELOPE FUNCTIONS AND EXCITON BINDING-ENERGIES IN (GA, IN)AS-GAAS QUANTUM-WELLS

We have performed a self consistent calculation for both the heavy-hol e and light-hole excitons in (Ga, In)As-GaAs quantum wells. The self-c onsistent light-hole wave function has been found to peak either in th e alloy layer or in the GaAs layer, depending both on the indium conte nt and thickness of the (Ga, In)As layer. We have calculated the avera ge light-hole and electron positions and have found that both type I a nd type II excitons can be obtained from a type II band to band profil e with a marginal light-hole potential in agreement with spin orientat ion measurements.