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.
Band structure of semiconductor alloys beyond the virtual crystal approximation. effect of compositional disorder on the energy gaps in GaPxAs1−x
Abstract A general method to study the band structure of compositionally disordered semiconductors is proposed. The effects of chemical disorder are added to the virtual-crystal band structure using the pseudopotential method and second order perturbation theory. In GaPxAs1−x, chemical disorder is shown to give a significant contribution to the experimentally observed non-linear behaviour of the lowest energy gaps as function of composition.
Characterization of Aqueous Dispersions and Gels Made of Sodium Caseinate and Basil Seed Gum: Phase Behavior, Rheology, and Microstructure
The interactions between sodium caseinate (NaCas) and basil seed gum (BSG) in the presence of calcium chloride (CaCl 2 ) were investigated. The phase behavior of the mixed aqueous dispersions and their gels revealed a homogeneous mixture, obtained at the higher concentrations of both CaCl 2 and BSG. The Herschel-Bulkley model sufficiently fitted the flow behavior of the mixture solution data. Apparent viscosity increased significantly ( p  < 0.05) by increasing the concentration of BSG, where the addition of CaCl 2 had no significant effect on the viscosity of the samples ( p  > 0.05). Furthermore, there was an increase in thixotropy due to the higher concentrations of BSG and CaCl 2 . Based on the frequency sweep test, at the low frequencies, a more gel-like behavior was observed in the case of the higher concentrations of either BSG or CaCl 2 . The rheological and SEM data suggested that the stronger structure of NaCas-BSG gel in the presence of the higher concentrations of CaCl 2 was related to the induction of complex formation between the two biopolymers.