Indium segregation and reevaporation effects on the photoluminescence properties of highly strained InxGa1−xAs/GaAs quantum wells

Temperature dependence of the effective band gap (BG) energy of strained InxGa1−xAs/GaAs single-quantum well and multi-quantum well structures grown by solid source MBE at varied substrate temperature is investigated by photoluminescence spectroscopy between View the MathML source and room temperature. For low-temperature-grown heterostructure, the temperature-induced BG shrinkage exhibits a good correlation with that of unstrained material. However, no consensus is shown to occur for a relatively high-temperature-grown quantum wells (QWs). This discrepancy is interpreted in terms of indium segregation and reevaporation during epitaxy. The low-temperature range, where the well-known Varshni law fails to fit PL peak positions, is found to decrease with increasing QW width and is attributed to the interface-roughness-induced exciton localization. This study was propped by numerical solving of Schrödinger equation taking into account strain, indium segregation and desorption effects.