Photoreflectance (PR) and photoluminescence (PL) measurements have been carried out in order to study the V/III flux ratio effect in type-II InP/InAlAs/InP heterostructures grown on a substrate InP (311), with polarity A and B by metal-organic chemical vapor deposition (MOCVD). PL and PR studies in InP/InAlAs/InP heterostructures demonstrate a strong dependence of the optical properties on the V/III molar ratio. EspeciallyIn particular, the Type II interface recombination ishas shown strong dependence on AsH3 overpressure and substrate polarity. Therefore, the arsenic overpressures (V/III) used have an effect on the piezoelectric field (Franz-Keldysh effect) and the As/P exchange. The shift of energy transition type II with respect to the V / III flow ratio variation on (311)A substrate is the opposite of (311)B substrate. thisThis is explained by the atomic terminated surface [A (In face) or B (P face)] of the substrate. For the InAlAs/InP heterostructures, PR signals corresponding to Franz-Keldysh oscillation (FKO) in the InP substrate have been observed. Analysis of their period has allowed one to determine the value of the piezoelectric field in InP substrate. This result enables evaluation of the shift of energy transition type II of the effect of V/III ratio and substrate polarity in such heterostructures.