We report on photoluminescence and photoreflectance studies of metalorganic chemical vapor deposition grown InGaAs/InGaAlAs quantum well structures on lattice matched InGaAs substrates. The optical characteristics of the substrates are also discussed. The quantum wells exhibit a high degree of relaxation, despite their thickness being below the critical values, which may be related to the growth conditions. A correlation was found between the optical characteristics and the quality of the layer structures grown on the InGaAs substrates. ©1997 American Institute of Physics.