Low-Pressure OMCVD Growth of AlGaAs Vertical Quantum Wells on Nonplanar Substrates

AlGaAs vertical quantum well structures were formed by low-pressure (20 mbar) organometallic chemical vapor deposition on V-grooved substrates. Ga segregation in the wells of these structures was evidenced by means of atomic force microscopy and photoluminescence experiments. Transmission electron microscopy cross sections resolve different branches in the well. This substructure, whose definition is enhanced in low-pressure growth, is associated with the formation of specific facets at the bottom of the grooves. The dependence of the growth rate on the crystallographic facet and the Al mole fraction is the key mechanism for the establishment of the self-limiting profile in the V-grooves.