We report investigations of layered structures whose modulated reflectance spectra not only have features that
suggest the occurrence of spatially indirect transitions but also display anomalous electric field effects. The spatially
indirect transitions can occur from either the GaAs conduction or valence band to quantum levels of carriers confined
between narrow potential barriers. In addition to the usual band-to-band excitonic transitions, we discuss spatially
direct transitions between the conduction band and the two-dimensional hole states that exist in a spacer layer
separating heavily-doped GaAs regions from AlGa1_As barriers. Finally, we comment on spectral lineshapes
asssociated with built-in electric fields that differ from those predicted using Franz-Keldysh theory. The energies
of all transitions are compared with those calculated using potential profiles based upon the growth parameters.