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Low-temperature photoluminescence (PL) has been studied in several III-V single-quantum-well (SQW) samples. We have observed shifts of the PL peak energy as a function of the excitation intensity which, we show, are due to the quantum confined Stark effect (QCSE) caused by the internal electric field at the surface and/or heterointerfaces in the samples. The experimentally measured PL peak shifts in ${\mathrm{In}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As/GaAs and ${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As/GaAs SQW's are compared with calculations based on the QCSE and excellent agreement is found. The magnitude of the internal field determined from the PL analysis coincides with the value for the electric field obtained from photoreflectance measurements on the same samples, at the same temperatures. \textcopyright{} 1996 The American Physical Society.

An optical modulation technique has been used to observe the electromodulation of photoluminescence in single and multiple quantum wells. It is shown that this photomodulated photoluminescence technique can yield similar information to that obtained from electroabsorption and photoabsorption experiments but, because it does not require special sample geometry or sample preparation, it is easier to implement, especially in the case of samples grown on nontransparent substrates.

We have developed a new technique of modulated photoluminescence (PL) spectroscopy. We show that the signal detected at twice the modulation frequency of the exciting light contains information about the non-linear processes similar to photo-modulated PL experiments. We attribute this non-linear PL signal to the optical modulation of the internal electric field of the quantum well (QW) samples. The method allows the separation of overlapping PL emission lines and provides the emission parameters of the separated lines, even when the PL spectrum itself appears to be featureless.

In this paper, we shall describe a modulated photoluminescence technique which, in semiconductors quantum wells, provides results similar to the conventional electromodulated absorption measurements. The advantage of this new technique is that it can be used on as grown samples or devices without the need for elaborate sample geometries or sample preparation which are necessary in the modulated absorption measurements.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.