Browsing by Subject "Poisson"

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    Effect of various pseudomorphic AIN layer insertions on the electron densities of two-dimensional electron gas in lattice-matched In0.18AI0.82N/GaN based heterostructures
    (Institutul National de Cercetare-Dezvoltare pentru Optoelectronica, 2009) Lisesivdin, S. B.; Özbay, Ekmel
    We explored the effects of various pseudomorphic AlN layer insertions in lattice-matched In0.18Al0.82N/GaN based heterostructures on band structures and carrier densities with the help of one-dimensional self-consistent solutions of non-linear Schrödinger-Poisson equations. According to the calculations, important increase in carrier density is expected with an increasing number of AlN insertions in In0.18Al0.82N barrier. The effect of the position of an AlN layer in In0.18Al0.82N barrier is also investigated. An additional AlN layer insertion in the GaN layer is calculated in detail with the help of an experimental point of view, in which the possible effects on both carrier density and mobility are discussed.
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    Numerical optimization of Al-mole fractions and layer thicknesses in normally-on AlGaN-GaN double-channel high electron mobility transistors (DCHEMTs)
    (Institutul National de Cercetare-Dezvoltare pentru Optoelectronica, 2009-05) Atmaca, G.; Elibol, K.; Lisesivdin, S. B.; Kasap, M.; Özbay, Ekmel
    We explored the effects of the Al-mole fraction (x) of AlxGa1-xN barrier layers and the thickness of some layers on carrier densities and electron probability densities in normally-on AlGaN-GaN double-channel high electron mobility transistors. Investigations were carried out by solving nonlinear Schrodinger-Poisson equations, self-consistently including polarization induced carriers that are important for GaN-based heterostructures and twodimensional electron gas (2DEG) formation. Strain relaxation limits were also calculated, in which optimized cases were found for the investigated Al-mole fraction and thickness values under pseudomorphic limits. The effect of the investigated thickness changes on electron probability densities show no important change in the overall simulations. In addition to a carrier increase in the selected optimum cases, reasonable mobility behavior is also expected.
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    ItemOpen Access
    Numerical optimization of In-mole fractions and layer thicknesses in AlxGa1-xN/AlN/GaN high electron mobility transistors with InGaN back barriers
    (ELSEVIER, 2011-02-01) Kelekci, O.; Lisesivdin, S. B.; Ozcelik, S.; Özbay, Ekmel
    The effects of the In-mole fraction (x) of an InxGa 1-xN back barrier layer and the thicknesses of different layers in pseudomorphic AlyGa1-yN/AlN/GaN/InxGa 1-xN/GaN heterostructures on band structures and carrier densities were investigated with the help of one-dimensional self-consistent solutions of non-linear SchrdingerPoisson equations. Strain relaxation limits were also calculated for the investigated AlyGa1-yN barrier layer and InxGa1-xN back barriers. From an experimental point of view, two different optimized structures are suggested, and the possible effects on carrier density and mobility are discussed.