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-µm 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 ºC, and a 42-nm additional blue-shift is obtained at 750 ºC 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 ºC and is attributed to the migration of nonra-diative 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.