Exciton localization effects and heterojunction band offset in (Ga,In)P-(Al,Ga,In)P multiple quantum wells

Disordered ${\mathrm{Ga}}_{0.52}$ ${\mathrm{In}}_{0.48}$P- (${\mathrm{Al}}_{0.7}$ ${\mathrm{Ga}}_{0.3}$ ${)}_{0.52}$ ${\mathrm{In}}_{0.48}$P bulk and quantum-well epilayers, lattice matched to GaAs substrates misoriented from (100), have been studied by low-temperature photoluminescence (PL) and photoluminescence excitation spectroscopy (PLE). The effects of excitonic weak localization are discussed by comparison between the PL and PLE data. Envelope-function fitting of the excitonic transitions observed in PLE has been used to determine a conduction-band discontinuity Δ${\mathit{E}}_{\mathit{c}}$ of ∼0.67Δ${\mathit{E}}_{\mathit{g}}$, providing strong support for the value obtained by Liedenbaum et al. [Appl. Phys. Lett. 57, 2699 (1990)].