The effect of annealing on the photoluminescence (PL) in GaAsSbN/GaAs quantum well (QW) grown by solid-source molecular-beam epitaxy (SS-MBE) has been investigated. Low-temperature (4 K) PL peaks shift to higher energy sides with the increase of annealing temperature. An AsSb atomic interdiffusion at the heterointerface is proposed to model this effect. The compositional profile of the QW after interdiffusion is modeled by an error function distribution and calculated with the 10-band k-p method. When the diffusion length equals to 1.4 nm, a corresponding transition energy blueshift of 36 meV is derived. This agrees with the experimental result under the optimum condition (750 degrees C at 5 min). (c) 2006 Elsevier B.V. All rights reserved.