Photoluminescence measurements have been performed on GaAs quantum wells under an electric field perpendicular to them. With an increasing field, the intensity decreases and becomes completely quenched at an average field of a few tens of kV/cm. This is accompanied by a shift to lower energies of the peak positions. The results are interpreted as caused by the field, which induces a separation of electrons and holes and modifies the energies of the quantum states. © 1983.