Electron transport in ZnMgO/ZnO heterostructures

Abstract

We numerically calculate the wave function of two-dimensional electron gas (2DEG) for use in 2DEG transport theory and study the electron transport in ZnMgO/ZnO heterostructures. For strongly confined 2DEG, the temperature dependence of the electron mobility is satisfactorily explained using 2DEG transport theory. The interface roughness and ionized impurity scatterings play important roles in the electron transport at low and moderate temperatures. At room temperatures polar optical phonon scattering is the most important scattering mechanism. For heterostructures having two parallel conduction paths in the 2DEG at the ZnMgO/ZnO interface and in the ZnO thick layer, the electron transport is contributed by the two paths. We calculate the mobility for the respective conduction paths, and then combine the two mobility components to fit the experimental data. The theoretical calculations are in good agreement with the experimental data.

Electrochemical behavior of tartaric acid at CuGeO3 nanowire modified glassy carbon electrode

“…Furthermore, with the scan rate increasing from 50 to 200 mV s −1 , the intensity of the CV peaks increases obviously. In addition, the potential of the anodic and cathodic peaks of the tartaric acid at the CuGeO 3 nanowire modified glassy carbon electrode shifts negatively with the increase of the scan rate which is similar to that reported by Li et al [19]. The role of the scan rate on the oxidation current of the tartaric acid is also analyzed which is shown in Fig.…”

Conduction band fluctuation scattering due to alloy clustering in barrier layers in InAlN/GaN heterostructures

“…The detailed description of these scattering mechanisms can be found elsewhere. 15,25,26 The defect parameters are set with the following values: the standard deviation of In mole fraction ∆ = 0.13 and the correlation length Λ = 10 nm, the dislocation density N DIS = 10 9 cm 2 , the ionized impurity densities N 1 = 3 × 10 18 cm 3 , N 2 = 1 × 10 17 cm 3 , the root-mean-square interface roughness of 0.42 nm, and the horizontal correlation length of interface roughness of 5 nm. The total mobility is calculated using Matthiessen's rule:…”

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“…High mobility 2DEGs require a low density of scattering centres. These can be formed by crystalline defects [8], ionized donors [9], alloy scattering [8], electron-electron scattering [10] or atomic impurities [11]. Minimizing the crystalline defect density requires the use of an epitaxially matched substrate, with the best results found using single-crystal ZnO [2].…”

“…In MBE-grown ZnO/ZnMgO 2DEGs, interface roughness scattering and impurity scattering have been shown to be the dominant factors for electron mobility [8]. It is known, for instance, that lithium acts as an acceptor in ZnO and can significantly reduce ZnO conductivity [15][16][17] and harm 2DEG formation [11]. Atomic impurities are known to be present in ZnO substrates and are incorporated during hydrothermal growth [16].…”