Near-ideal low threshold behavior in (111) oriented GaAs/AlGaAs quantum well lasers

Abstract

Fundamental characteristics of (111) oriented GaAs/AlGaAs graded‐index separate‐confinement‐heterostructure single quantum well lasers have been compared with conventional (100) oriented lasers. In particular, the threshold current density J_th of (111) oriented lasers does not change with the well width L_z in the range of L_z=30–100 Å, which corresponds to an ideal extreme. The lowest J_th of 145 A/cm² together with a high characteristic temperature T₀ of 186 K in the threshold‐temperature dependence has been achieved for an L_z of 40 Å and a cavity length of 490 μm. The dependence of T₀ on L_z showed that T₀ is maximum at L_z∼60 Å for both (111) and (100) oriented lasers.