Photoluminescence and microcathodoluminescence spectra of thick-film GaAsN and InGaAsN structures and GaAs/InGaAsN, AlGaAs/InGaAsN quantum wells (QWs) were studied for InGaAsN layers with low nitrogen concentration of 0.35-0.5%. It is shown that in thick-film structures the bandedge luminescence intensity is strongly decreased in the row homoepitaxial GaAs, GaAsN on GaAs buffer, GaAsN, GaAs on GaAsN buffer, InGaAsN which correlates with the increasing concentration of electron traps with activation energy 0.53-0.55 eV. The type of defect bands in the thick-film structures was found to strongly depend on composition of the layers. For the GaAs/InGaAsN QW structures the intensity of luminescence was found to be more than an order of magnitude higher than in InGaAsN single films. (C) 2002 Elsevier Science Ltd. All rights reserved.