The effect of an InP cap layer on the photoluminescence of an InxGa1–xAs1–yPy/InzAl1– zAs quantum well heterostructure

The effect of an InP cap on the photoluminescence (PL) spectrum of an InGaAsP/InAlAs quantum well (QW) is investigated using excitation power and temperature dependent PL. An as-grown sample with the InP cap layer shows an inverted interface created between InP and InAlAs that has a transition energy very close to the transition energy of the QW; consequently, there is an overlap between them. On the other hand, the QW sample with the cap layer etched away does not have a feature due to the inverted interface; even at very low power, the only observed feature is due to the QW transition.