Molecular beam epitaxial growth and photoluminescence of near-ideal GaAs-AlxGa1−xAs single quantum wells

Abstract

Single quantum wells with ∼120‐Å GaAs wells and Al_0.3Ga_0.7As or GaAs‐Al_0.3Ga_0.7As superlattice barriers were grown by molecular beam epitaxy under conditions known to produce very high‐purity material. Low‐temperature photoluminescence measurements indicate that the dominant recombination transitions are associated with free and bound excitons involving both light and heavy holes. A forbidden transition, possibly E_21h, is also observed. The transition associated with electron‐heavy‐hole free excitons is most intense and has a linewidth of 0.3 meV at 2 K. The linewidths observed for these samples, grown with As₄ species at 630 °C, are the smallest for 120‐Å single quantum wells and are close to theoretically calculated limits.