The influence of antimony (Sb) incorporation on the optical properties of AlAs/GaAs quantum wells (QWs) grown by solid source molecular beam epitaxy (SSMBE) has been investigated by room- and low-temperature photoluminescence (PL) measurements. Various Sb fluxes are used in an growing AlAs barrier layer. The room- and low-temperature PL measurements showed that incorporation of a very small amount of Sb doping can decrease the PL linewidths and increase the PL intensity of AlAs/GaAs QWs drastically, which indicates that Sb improves the interface and crystal quality as both a surfactant and an isoelectronic dopant in AlAs. However, the PL intensity reduces, and full-width at half-maximum (FWHM) of QWs increases with the increase of Sb flux, indicating that a little high concentration of Sb incorporated into the alloy and degrades the interfacial and crystalline quality. It is attributed to the strain-induced defects in the barrier layers of AlAs. Moreover, we also use the infinite square potential well model to study the relation of the interface roughness and FWHM. © 2005 Elsevier B.V. All rights reserved.