Very low current threshold GaAs-AlxGa1−xAs double-heterostructure lasers grown by molecular beam epitaxy

Abstract
GaAs‐AlxGa1−xAs (x=0.3) double‐heterostructure (DH) lasers having very low current threshold densities have been prepared by molecular beam epitaxy (MBE). For DH lasers having Al‐mole‐fraction differences between the active layers and AlxGa1−xAs confinement layers Δx∼0.3, the best of the MBE‐grown DH laser wafers have averaged current threshold densities similar to those obtained from the best of similar‐geometry DH lasers prepared by liquid‐phase epitaxy (LPE) and by metalorganic chemical vapor deposition (MO‐CVD). With Δx=0.3, the lowest averaged current threshold density achieved is 800 A/cm2 (without reflective coating) for a wafer with an active layer thickness of 0.15 μm.