Optical and structural properties of InGaAs/InP single quantum well structure grown on GaAs substrate with linearly graded metamorphic InGaP buffer layer by solid source molecular beam epitaxy (SSMBE) using a valved phosphorus cracker cell have been investigated. X-ray diffraction measurements were carried out to investigate the strain relaxation behavior of the metamorphic buffers grown at different temperatures, and the degree of relaxation was found to be 96%. Photoluminescence (PL) measurements show comparable results with the PL response observed for a lattice matched InGaAs/InP quantum well grown on InP substrate. The growth temperature of the metamorphic buffer layer ranging from 430 to 480 degreesC was found not to influence the strain relaxation ratio and the PL results. The results presented suggest that linearly graded InGaP metamorphic buffer layers grown by SSMBE can be used to decouple the InGaAs/InP quantum well structure from the GaAs substrate. (C) 2002 Published by Elsevier Science Ltd.