Nuytten, Thomas and Hayne, Manus and Bansal, Bhavtosh and Liu, H. Y. and Hopkinson, Mark and Moshchalkov, Victor V. (2011) Charge separation and temperature-induced carrier migration in Ga1−x Inx N y As1− y multiple quantum wells. Physical review B, 84: 045302. ISSN 1550-235X
Abstract
We have investigated the photoluminescence (PL) of two carefully selected dilute nitride Ga1−xInxNyAs1−y multiple quantum well structures in magnetic fields up to 50 T as a function of temperature and excitation power. The observation of a nonmonotonic dependence of the PL energy on temperature indicates that localized states dominate the luminescence at low temperature, while magneto-PL experiments give new insights into the nature of the localization. We find that the low-temperature spatial distribution of carriers in the quantum well is different for electrons and holes because they are captured by different disorder-induced complexes that are spatially separated. A study of the thermalization of the carriers toward free states leads to the determination of the free-exciton wave-function extent in these systems and enables an assessment of the localization potentials induced by inhomogeneity in the quantum well.