Improvement of quantum efficiency of MBE grown AlGaAs/InGaAs/GaAs edge emitting lasers by optimisation of construction and technology

In this paper, we compare theoretically, as well as experimentally, four constructions of quantum well (QW) AlGaAs/InGaAs/GaAs semiconductor lasers: one standard, simple separate confinement heterostructure (SCH) laser and three different GRIN SCH (graded index separate confinement heterostructure) lasers. By optimising the construction and technology of epitaxy, an increase of laser quantum efficiency was obtained for the wavelength 980 nm. The highest measured quantum efficiencies approach those predicted theoretically. The recommended growth conditions ensuring obtaining the best laser parameters are given.