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Presents low-temperature photoluminescence studies of nominally undoped gallium arsenide quantum wells in which weak acceptor-related emissions can be observed. Experimental details; Determination of the impurity profile; Conclusion.

The optical response of a GaAs-Ga(Al)As one-side-modulation-doped quantum well is studied by photoluminescence and excitation spectroscopy at T=2 K. The electronic concentration is controlled in a field-effect-transistor-like structure. 1011 cm-2 electrons are sufficient to wipe out the strong excitonic resonances which dominate the photoluminescence excitation spectrum when the well is depleted of its carriers. While the lowest lying excitation peak coincides with the maximum of the photoluminescence line when the GaAs channel is empty, the two peaks move in opposite directions with increasing carrier concentration due to the inflating Fermi surface and to band-gap renormalization effects. [ABSTRACT FROM AUTHOR]