In0.78Ga0.22As/In0.78Al0.22As quantum wells and In0.84Ga0.16As photodetctor samples have been grown on InP-based InxAl1-xAs metamorphic graded buffers to investigate the effects of compositional overshoot on the material characteristics. Atomic force microscopy results show that the surface roughness is reduced by the compositional overshoot in the InAlAs buffer layers for both the quantum well and photodetector samples. In the case of thin quantum wells, X-ray diffraction reciprocal space mapping and photoluminescence measurements show that the use of compositional overshoot can increase the relaxation degree, reduce the residual strain and improve the optical quality. While in the case of thicker photodetectors, no obvious improvement is observed after using compositional overshoot. The different behaviours of the metamorphic quantum wells and photodetectors should be considered in the device applications.