Toshiyuki Higashino

Band-gap change in ordered/disordered GaAs1-ySby layers grown on (001) and (111)B InP substrates

GaAs1-ySby ternary layers were grown on (001) and (111)B InP substrates by molecular beam epitaxy (MBE), and were characterized using optical absorption measurements and transmission electron diffraction (TED) measurements. A marked band-gap change was observed between the GaAsSb layers grown on (001) InP substrate and those grown on (111)B InP substrate. It was found that the band-gap change corresponds to the CuPt-type ordered/disordered structure in GaAsSb layers grown on (001) and (111)B InP substrates.

Molecular Beam Epitaxial Growth and Characterization of GaAs1-ySby Layers on (111)B InP Substrates

GaAs1-ySby layers were grown on (111)B-oriented InP substrates by molecular beam epitaxy (MBE), and their electrical and optical properties were characterized. It was found that the Sb mole fraction of the (111)B samples is larger than that of the (100) samples. The surface morphology of the (111)B samples was very sensitive to the V/III ratio, compared to that of the (100) samples. Furthermore, the band-gap energy of the (111)B sample was found to be larger than that of the (100) sample from the photoluminescence and optical absorption measurements. The mechanism of the band-gap energy shift was discussed based on the spontaneous ordering of alloys.

Electroluminescence of In0.53Ga0.47As/GaAs0.5Sb0.5 Type-II Multiple Quantum Well Light-Emitting Diodes Grown on (111)B InP by Molecular Beam Epitaxy.

In0.53Ga0.47As/GaAs0.5Sb0.5 type-II multiple-quantum-well (MQW) light-emitting diodes were grown on (111)B InP substrates by molecular beam epitaxy. The peak wavelength of the electroluminescence (EL) was at 2.08 µm at 11 K and at 2.28 µm at 300 K. It was found that the EL intensity of the type-II MQW diode on (111)B substrates was about one order of magnitude stronger than that on (100) InP substrates, which can be explained by the improved crystal quality of the MQW diode on the (111)B InP substrate.

Molecular beam epitaxial growth and characterization of GaAs/sub 0.5/Sb/sub 0.5/ layers on [111]B InP substrates

GaAs/sub 0.5/Sb/sub 0.5/ layers were grown on [111]B oriented InP substrates by molecular beam epitaxy (MBE). It was found that the Sb mole fraction of the [111] samples is higher than that of [100] samples. Furthermore, the band gap energy of the [111] sample was found to be larger than that of the [100] sample from photoluminescence and optical absorption measurements. The mechanism of the band gap energy shift was discussed based on the spontaneous ordering of alloys.