Improved optical qualities of GaAs/Al0.3Ga0.7As tilted T-shaped quantum wires fabricated by glancing-angle molecular beam epitaxy

High-quality GaAs/Al0.3Ga0.7As tilted T-shaped quantum wires (tilted T-QWRs) were fabricated with a two-step growth of molecular beam epitaxy (MBE), which consists of glancing-angle MBE growth of GaAs/Al0.3Ga0.7As multi-quantum well (MQW) layer (five 6.6 nm thick GaAs wells) on a reverse-mesa etched (1 0 0) GaAs substrate and MBE over growth of GaAs/Al0.3Ga0.7As/single-quantum well (SQW) (7.3 nm well width) on a (1 1 1)B facet. This new technique enable us to fabricate lots of tilted T-QWRs over a large area of a GaAs substrate surface. Full-width-at-half maximum (FWHM) of a cathodoluminescence (CL) peak from the tilted T-QWRs was reduced down to 10 meV at 78 K, which is almost comparable with those of GaAs/AlGaAs T-QWRs fabricated by the cleaved-edge overgrowth.