Fabrication of band-gap tuned lasers in GaAs/AlGaAs structure using one-step rapid thermal process

We report here on the development of a new quantum well intermixing technique in GaAs/AlGaAs laser structure. This technique employs a grown-in AlAs sacrificing layer as intermixing source and with the same layer, but oxidized by using a one-step rapid thermal process (RTP), as the intermixing mask. Selective intermixing could therefore be achieved across the wafer using a one-step RTP cycle. From the photoluminescence measurement at 77 K, the differential bandgap shift of as large as 47 meV has been observed from the masked and oxidized regions. Band-gap tuned lasers have been fabricated from the intermixed samples. The current threshold density of the intermixed lasers are higher than that of the as-grown and control lasers, but are kept below 12% for the most blue-shifted devices. The device characteristics of the bandgap tuned lasers confirm that the grown-in and the oxidized AlAs layer could be used as QWI source and mask respectively in the fabrication of photonics integrated circuits.