Band gap blue shift of InGaAs/InP multiple quantum wells by different dielectric film coating and annealing

Band gap blue shift of InGaAs/InP multiple quantum well (MQW) structures by impurity-free vacancy disordering (IFVD) is studied by photoluminescence (PL) and secondary ion mass spectrum (SIMS). SiO2, Si3N4, and spin on glass (SOG) were used for the dielectric layers to create the vacancies. The results indicate that the band gap blue shift varies with the different dielectric layers and depends on the annealing temperature. The blue shift is also related to the combination of the layers between dielectric and cladding layers. The SIMS profile shows that the dielectric capped layer and rapid thermal annealing caused the quantum well intermixing, which results in the band gap blue shift. Optimum condition can be reached by choosing suitable dielectric layer and annealing condition.