Pseudo-potential calculations of the electronic and optical properties of GaxAlyIn1–x–yAs
A method for calculating the electronic structure of the quaternary alloy GaAlInAs is presented with zinc blende structure. We have used the empirical pseudo-potential method coupled with the virtual crystal approximation (VCA). The electronic structures are studied for GaAlInAs (x = 0.24, y = 0.24) and GaAlInAs lattice matched to InP as well GaAs. In addition a method for calculating the refractive index is presented, which we used the Sellmeir model. The composition dependence of the refractive index is discussed, the results indicate that refractive index decrease with alloying composition of the quaternary alloy GaAlInAs lattice matched to InP and GaAs.
Fabrication and characterisation of long-wavelength, GaInAs/AlGaInAs/InP modified-MQW lasers
Room-temperature operation of GaInAs/AlGaInAs/InP M-MQW lasers grown by low-pressure MOVPE is described for the first time. Threshold current densities were as low as 1.9 kAcm-2 with emission wavelengths of 1.59 μm.
Composite monolayer fabrication by an arc-spray process
A single layer (monotape) technique for fabricating complex high-temperature tungsten-fiber-reinforced superalloy composites is proposed. The fabrication of sheets of arc-sprayed monotape 38 cm wide and 122 cm long has been demonstrated. Composites fabricated using the method are shown to have equal tensile strength and a cleaner matrix than composites fabricated from powder metal cloth monotapes, and the present technique is less expensive than the powder metal fabrication techniques.