Low-threshold disorder-defined native-oxide delineated buried-heterostructure AlxGa1−xAs-GaAs quantum well lasers

Abstract

Impurity-induced layer disordering (IILD) along with oxidation (native oxide) of high-gap AlxGa1−xAs confining layers is employed to fabricate low-threshold stripe-geometry buried-heterostructure AlxGa1−xAs-GaAs quantum well heterostructure (QWH) lasers. Silicon IILD is used to intermix the quantum well and waveguide regions with the surrounding confining layers (beyond the laser stripe) to provide optical and current confinement in the QW region of the stripe. The high-gap AlxGa1−xAs upper confining layer is oxidized in a self-aligned configuration defined by the contact stripe and reduces IILD leakage currents at the crystal surface and diffused shunt junctions. AlxGa1−xAs-GaAs QWH lasers fabricated by this method have continuous 300 K threshold currents as low as 5 mA and powers ≳ 3l mW/facet for ∼ 3-μm-wide active regions.