Exciton Binding Energy in Small-Period GaAs/Ga _{(1- x )} Al _x As Superlattices

Abstract

We report the optical determination of exciton binding energies in small-period GaAs/Ga0.7Al0.3As superlattices by means of low-temperature photoluminescence excitation spectroscopy and photoluminescence spectroscopy as a function of temperature. The heavy-hole exciton binding energy decreases with decreasing superlattice period. Our experimental findings are in reasonable agreement with a variational calculation.

Variational tight-binding theory of excitons in compositionally modified semiconductor superlattices

“…It should be noted that the authors of Ref. [7] also provided the results of a variational calculation which are in satisfactory agreement with the experimental data. Other theoretical calculations giving comparable results can be found in the articles of Ref.…”

“…The experimental values and their corresponding error bars, given in Ref. [7], are reproduced in Fig. 5.…”

“…The exciton binding energy has been measured [7] by optical methods for GaAs/Al 0.3 Ga 0.7 As superlattices which feature equal well and barrier thicknesses. The experimental values and their corresponding error bars, given in Ref.…”

“…by Bastard and co-workers [1,7] in the context of strictly periodic superlattices. To demonstrate the effectiveness of our separable trial function, we also calculate the exciton binding energy for a specific periodic superlattice (i.e.…”

Interwell excitons in GaAs superlattices

“…The gradual transition of the electronic and optical properties, from isolated quantum wells to those of a threedimensional solid for increasing miniband width, has been studied earlier experimentally [1][2][3] and theoretically. 1,4,5 These reports were focused on the observation of the predicted M 1 exciton associated with the upper miniband edge. The quality of the experimental data was recently disputed, 6,7 and attempts were made using photocurrent and photoreflectance spectroscopy in addition to excitation spectroscopy.…”