Blueshifting of InGaAsP-InP laser diodes using a low-energy ion-implantation technique: comparison between strained and lattice-matched quantum-well structures

Blueshifted InGaAsP-InGaAs-InP laser diodes have been fabricated using a technique that includes a low-energy ion implantation, used to generate point defects near the surface of the structure, followed by a thermal anneal which causes the diffusion of these defects through the quantum wells (QWs). This diffusion of point defects induces a local intermixing of atoms in the QWs and barriers, which results in a decrease in the emission wavelength of the devices. Results obtained with strained and lattice-matched QW structures are compared. For lattice-matched structures, electroluminescence wavelength shifts as large as 76 nm were obtained. Strained QW structures presented a much smaller blueshift (≈10 nm). In both cases, we observed no significant change of the threshold current caused by the intermixing process