Energy-dispersive X-ray spectroscopy, optical reflectance and photoluminescence were used to study the properties of InAsSbP barrier layers in InAsSb/InAsSbP heterostructures (HSs) and their effect on the performance of HSs. A  deviation of the chemical composition of the layers from the specified value and acceptor-like states in their bandgap were found. These features defined the nature of radiative transitions in the HSs.