Characterization of GaInAsP/InP double heterostructure laser-wafers

GaInAsP/InP four and five-layer double heterostructure (DH) laser wafers are grown using a single step liquid phase epitaxial process. With help of the scanning electron microscopy, injection, and photoluminescence the structure parameters, quantum efficiency, and doping level are investigated. As a result, the p-n junction is located in the upper cladding layer and the distance from the interface between the active and confinement layer is less than the experimentally observed diffusion length of excess carriers. The threshold currents of MCRW lasers (Ith; resonator width and length 3.5 and 200 μm, respectively) as a function of the active region thickness (t) elucidate a broad minimum around t = 0.15 μm. The values Ith < 20 mA reveal an excellent structure design and an optimized material quality. (author)