The effects of InP grown by He-plasma assisted epitaxy on quantum-well intermixing

He-plasma assisted InP (He*-InP) layers grown by gas source molecular beam epitaxy (GSMBE) have been employed to enhance quantum well (QW) intermixing induced by rapid thermal annealing in a 1.5-mum InGaAsP QW laser structure. Inserting a 40-nm He*-InP layer just above the active region enhances the blue-shift for anneal temperatures larger than 680 degreesC, and a 42-nm additional blue-shift is obtained at 750 degreesC for samples with the He*-InP layer, compared to samples with normal InP replacing the He*-InP, This is accompanied by a reduction in the photoluminescence (PL) intensity for anneal temperatures greater than 600 degreesC and is attributed to the migration of nonradiative defects from the He*-InP layer into the QWs, Insertion of a thin InGaAs layer between the He*-InP layer and the QW blocks the diffusion of these nonradiative defects into the QW. The results indicate that the He*-InP material could prove useful in QW intermixing to achieve integrated optoelectronic devices, in particular for high-frequency devices which require short carrier lifetimes.