Modulated beam growth and interface control in III-AsSb laser heterostructures

The molecular beam epitaxy of advanced heterostructures containing mixed arsenide/ antimonide layers presents a number of special challenges. A 5 /spl mu/m thick laser designed to emit mid-infrared radiation of 4 /spl mu/m wavelength, for example, may incorporate thick (/spl sim/2 /spl mu/m) lattice-matched AlGaAsSb layers for optical confinement, thinner (/spl sim/0.1 /spl mu/m) lattice-matched InGaAsSb layers for electrical confinement, and extremely thin (/spl sim/20 /spl Aring/) InAs and InGaSb layers as quantum wells. Such structures highlight the need for precise control of alloy composition over time on the one hand, and reproducible manipulation of the interfacial chemistry across very thin III-As and III-Sb layers on the other.