Selective band‐gap blueshifting of InGaAsP/InGaAs(P) quantum wells by thermal intermixing with phosphorus pressure and dielectric capping

Group V interdiffusion of strained and unstrained InGaAsP/InGaAs(P) quantum wells induced by thermal anneals at 650 °C with phosphorus gas pressure using photoluminescence spectroscopy and x‐ray diffraction measurements have been investigated. The blueshift of the annealed quantum well photoluminescence peak exhibits large variations with the phosphorus pressure, with a minimum around 0.1 atm. Samples capped with a SiO2 layer only exhibit minor blueshifts, thus demonstrating the possibility of spatially selective control of the intermixing. A differential blueshift as large as 80 meV is presently obtained between capped and uncapped areas. The interdiffusion of the quantum well interfaces is shown to be dependent on the layer strain.