Exciton Transitions in Narrow GaAs/Al x Ga l-x As Quantum Wells

Electroreflectance (ER) measurements were made on GaAs/AxGal-x As coupled quantum wells at room temperature and at 77K. The close coupling of the narrow (28.3 A) barriers resulted in splitting of the hole and electron subband levels which was observed at both temperatures. As a first approximation, the confining potential was assumed to be due to the barrier alone; electric field effects of the modulating potential and trapped interfacial charge were considered to be negligible. The dominant heavy holeconduction and light hole-conduction transitions observed at 300K were at 1523meV and 1539 meV respectively, although other weaker transitions were also resolved.