Near-equilibrium LPE growth of low threshold current density In1−xGaxAsyP1−y(λ=1.35 μm) DH lasers

Abstract

The growth of In1−xGaxAsyP1−y double heterostructure (DH) laser material by liquid phase epitaxy (LPE) under near-equilibrium growth conditions which produce small growth rates is described. Broad-area threshold current densities for this material are as low as 670 A/cm2 for 0.1-μm active layers which is the lowest value yet reported for this material system. This value is comparable with the best reported value for LPE Ga1−xAlxAs with a similar refractive index step. For comparison, material grown at higher growth rates using the commonly employed two-phase and supercooling techniques are found to give consistently higher threshold current densities than those grown under near-equilibrium conditions in the same LPE system. The spontaneous luminescence observed in window lasers grown by the near-equilibrium method appears uniform with no evidence of dark absorbing regions which could cause self-pulsations in the laser output during initial operation.