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Abstract. (Ga,In)As/GaAs/Ga(As,Sb) multi-quantum well heterostructures have been investigated using continuous wave and time-resolved photoluminescence spectroscopy at various temperatures. A complex interplay was observed between the excitonic type-II transitions with electrons in the (Ga,In)As well and holes in the Ga(As,Sb) well and the type-I excitons in the (Ga,In)As and Ga(As,Sb) wells. The type-II luminescence exhibits a strongly non-exponential temporal behavior below a critical temperature of T c = 70 K. The transients were analyzed in the framework of a rate-equation model. It was found that the exciton relaxation and hopping in the localized states of the disordered ternary Ga(As,Sb) are the decisive processes to describe the dynamics of the type-II excitons correctly.

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We have studied the optical properties of Ga(NAsP)-heterostructures, which were systematically grown at different temperatures by means of continuous-wave and time-resolved photoluminescence. We show that both the long ranged and the short ranged disorder scales increase for higher growth temperatures. Furthermore, samples with a higher disorder not only emit less photoluminescence (PL) intensity but also exhibit a longer effective PL decay time.