The allowed and forbidden transitions in MBE grown on (001) GaAs subst
rates (AlGa)As/GaAs multiple quantum well structures were investigated
by photoreflectance spectroscopy (PR). The optical transition energy
values obtained from experiment were compared with ones calculated by
using the envelope function approximation. Good agreement between both
results was found. The temperature dependence, down to the liquid nit
rogen temperature, of the 1 IH transition was analysed. (C) 1998 Elsev
ier Science Ltd. All rights reserved.