Luminescent characteristics of InGaAsP/InP multiple quantum well structures by impurity-free vacancy disordering

InGaAsP/InP multiple quantum wells with quantum well intermixing (QWI) have been prepared by Impurity-Free Vacancy Disordering (IFVD). The luminescent characteristics were investigated using photoluminescence (PL) and photoreflectance (PR), from which the band gap blueshift was observed. Si3N4, SiO2 and SOG (spin on glass) were used for the dielectric layer to enhance intermixing from the out-diffusion of Group III atoms. All samples were annealed by rapid thermal annealing (RTA). The results indicate that the band gap blueshift varies with the dielectric layers and the annealing temperature. The SiO2 capping was successfully used with an InGaAs cladding layer to cause larger band tuning effect in the InGaAs/InP MQWs than the Si3N4 capping with an InGaAs cladding layer. On the other hand, samples with the Si3N4–InP cap layer combination also show larger energy shifts than that with SiO2–InP cap layer combination.