Characteristic temperature study of GaAsP-AlGaAs tensile strained quantum well lasers

Temperature characteristics of tensile strained GaAs1-yPy-Al0.35Ga0.65As si ngle quantum well heterostructure laser diodes are examined. The dependence of the characteristic temperature (T-0) on the quantum well composition is systematically studied in broad-area stripe lasers with identical quantum well widths (115 Angstrom) and various cavity lengths. Laser diodes with 10 quantum well compositions ranging from y=0 (lattice matched) to 0.30 (simi lar to 1.1% tensile strain) and 5 cavity lengths ranging from 300 to 1500 m u m are examined. Characteristic temperatures are found to be maximized for small (but generally nonzero) quantum well phosphorus compositions, with a maximum value of T-0=159 K obtained for y=0.025, but decrease rapidly with increasing composition. Our results are analyzed via a theoretical model f or the characteristic temperature of the transparency current in separate c onfinement quantum well lasers and comparison of our observations with othe r measured laser characteristics. These analyses suggest that the observed local maximum in T-0(y) at small y is a tensile strain effect, whereas the decreased T-0(y) at large y results primarily from loss of carrier confinem ent and barrier recombination. (C) 2000 American Institute of Physics. [S00 21-8979(00)02022-3].