Hideki Takasaki

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 diodes lattice-matched to InP

Electroluminescence (EL) of In 0.53 Ga 0.47 As/GaAs 0.5 Sb 0.5 type II multiple quantum well (MQW) diodes lattice-matched to InP substrates grown by molecular beam epitaxy was studied. A type II emission was clearly observed at 2.4 μm at 300 K. Furthermore, the EL intensity of the type II MQW diodes was larger than that of the InGaAs double heterostructure (DH) diodes. Temperature and injection current dependences of the EL spectrum were also investigated.

Photoluminescence properties of In0.53Ga0.47As/GaAs0.5Sb0.5 type II quantum well structures lattice-matched to InP

The photoluminescence (PL) properties of In0.53Ga0.47As/GaAs0.5Sb0.5 type II multiple quantum well (MQW) structures, lattice-matched to InP substrates grown by molecular beam epitaxy (MBE), were studied. It was found that a tunneling-assisted type II emission at about 2.3 μm showed a remarkable Si-doping dependence. The PL intensity of the type II emission was found to decrease drastically when the Si-doping concentration exceeds 2×1017 cm−3, followed by a remarkable increase in the full width at half maximum (FWHM) of the PL spectrum. It became clear that the observed PL intensity decreased and the PL spectral broadening were related to Si activity into the GaAsSb layers.

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.