The electronic structure of severaln‐type GaAs samples containing ‘‘&dgr;‐doping’’ layers of Si have been studied using photoreflectance (PR) spectroscopy. Well‐defined oscillatory features due to electronic transitions well above the band gap are observed at 300 K and identified as Franz–Keldysh oscillations. The energy spacing and the intensity of the oscillations decrease with decreasing temperature as a consequence, we believe, of changes in the electric field due to the surface charges. Self‐consistent energy‐band calculations support the interpretation that the oscillatory structure is due to Franz–Keldysh effects. The imposition of magnetic fields up to 15 even at room temperature has a pronounced influence on the PR spectrum. Parallel fields suppress the oscillatory structure but cause a large increase in the PR peaks near the GaAs energy gap. At 4.2 K Landau‐like spectral features are observed for fields applied perpendicular to the doping layer.