Influence of AlxGa1−xAs layer thickness on threshold current density and differential quantum efficiency for GaAs−AlxGa1−xAs DH lasers

Measurements of the threshold current density Jth and differential quantum efficiency ηd havd been made on GaAs−Al0.3Ga0.7As double−heterostructure (DH) lasers to determine the effect of AlxGa1−xAs layer thickness on Jth and ηd. For DH lasers with active layer thicknesses near 0.12 μ, Jth increases and ηd decreases drastically for p−type Al0.3Ga0.7As layers less than ∼0.8 μ in thickness. This effect is also considered for other values of active layer thickness d, and AlAs mole fraction x.