Fermi-level pinning by misfit dislocations at GaAs interfaces has been investigated. n + -GaInAs was used to control the misfit dislocation density by varying of composition and epilayer thickness. Interfaces with zero or low dislocation densities are Ohmic to current flow, and become rectifying with increasing dislocation density. The "Schottky barrier height" increases with dislocation density in accordance with a simple physical model which assumes Fermi-level pinning at the dislocation. PACS numbers: 73.40.-c, 73.30.+y Recent experimental studies on the formation of Schottky barriers at III-V semiconductor surfaces and interfaces have resulted in a proliferation of theoretical models. For example, Schottky barrier formation has been described in terms of Fermi-level pinning by adatorn-induced native defects, 1 * 2 metal-induced gap states, 3 and the electronic and chemical properties of the interface metallurgy. 4 ' 5 Definitive testing of these models is complicated by the experimental difficulty of differentiating between metallurgical and structural (defect) effects at metal/III-V interfaces. In this paper we report the electrical properties of n-type GaAs interfaces having a controlled density of a certain type of structural defect: the misfit dislocation,, We have used w + -GaInAs as the "metal" and control the misfit dislocation density by varying composition and epilayer thickness. These interfaces are free of extraneous metallurgy since they are formed by relaxing strain at lattice-mismatched heterojunctions with slightly different compositions,,The dynamics of misfit dislocation formation is well known 6 and is shown schematically in Fig.

Apparent deviations from Paschen’s law, observed in ac plasma panels, have been resolved by generalizing the breakdown criterion to include the dependence of the secondary electron emission coefficient on E/p0. Incorporation of this dependence into the proposed effective coefficient involves consideration of both the back-diffusion phenomenon and the influence of E/p0 on the efficiency of metastable atom generation. Calculated voltage breakdown curves in pure neon and neon plus 0.1% argon mixture are in good agreement with experimental data for both the metal electrode dc discharges and the insulator-covered electrode discharges found in ac plasma panels.

The dynamics of a highpressure ac gas discharge between dielectric coated electrodes near breakdown threshold

A generalized expression has been derived for the effective secondary electron emission coefficient γ, in Penning mixtures which incorporates the effect of both the majority and minority ions. Specific calculations for ac panels having an Ne+0.1%Ar mixture show that even a relatively small value of γAr not only significantly lowers the breakdown voltages, but also moves the voltage minimum to higher p0d values and makes the right-hand side of the Paschen curve less steep. This sensitivity of the effective coefficient γ on γAr is sufficient to explain the critical dependence of the shape of the measured breakdown voltage curves in ac panels on minor changes in the surface properties of the deposited insulator surfaces.

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