Pulsed-laser-induced quantum well intermixing in GaInAs/GaInAsP laser structures

Summary form only given. The application of postgrowth bandgap tuning of III-V quantum well (QW) structures using pulsed-laser-induced disordering (P-LID) in photonic integrated circuits is an attractive alternative to selective growth and regrowth processes. P-LID is impurity free and offers direct writing capability. This technique also requires lower processing cost compared to quantum well intermixing (QWI) realized using ion implantation. We report a significant modification of the bandgap energy of GaInAs/GaInAsP laser structure using the P-LID technique. A Q-switched Nd:YAG laser with wavelength of 1.064 /spl mu/m, generating pulses of /spl sim/8 ns and pulse repetition rate of 10 Hz was used in the experiment. Samples were irradiated at room temperature with normal incidence to the surface and then annealed at 625/spl deg/C for 120 s using a rapid thermal processor. We demonstrate that the degree of intermixing is dependent on the pulse energy density and the irradiation time of the Nd:YAG laser. A maximum bandgap shift of up to 112 meV has been observed. The spatial resolution of this technique was shown to be better than 2.5 /spl mu/m. The effect of laser processing on the material structure was investigated using photoluminescence measurements and transmission electron microscopy.