(AlAs)(m)/(GaP)(n) short-period superlattices with (m, n) = (3, 3), (2, 3), (1,4) were grown on (0 0 1) GaAs substrates by gas-source migration-enhanced epitaxy at 400-degrees-C. The formation of the structures was confirmed by X-ray diffraction measurements and cross-sectional transmission electron microscopy analysis. A broad emission in the photoluminescence spectra was observed at approximately 550 560 nm in all the samples at low temperature. The origin of the peaks of the (AlAs)(3)/(GaP)(3) and (AlAs)(2)/(GaP)(3) samples was considered to be either the localization state or the energy band reflecting the zone-folding and band-mixing effect of the superlattices, while the peak of the (AlAs)(1)/(GaP)(4) sample was ascribed to defects in the layer or heterointerface roughness.