A Chaotic Potential of Charged Dislocations in Group III-Nitride Heterojunctions
TL;DR: In this paper, the structure of the chaotic potential caused by the electrostatic field of charged dislocations in group III-nitride heterojunctions is investigated, taking into account the spatial dispersion of the dielectric response of a two-dimensional electron gas.
Abstract: The structure of the chaotic potential caused by the electrostatic field of charged dislocations in group III-nitride heterojunctions is investigated. Taking into account the spatial dispersion of the dielectric response of a two-dimensional electron gas, the amplitude and scale of the chaotic potential in the junction plane are determined. It is shown that the parameters of the chaotic potential depend on the density of surface states and the concentration of dislocations.
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TL;DR: In this article , an intermodal fiber interferometer using the light from an incoherent broadband source has been considered analytically and implemented as a laboratory device, where the use of an optical spectrum analyzer and correlation functions approach in extracting the utility signal made it possible to achieve a linear response to the measured external perturbation and effective fading mitigation.
Abstract: An intermodal fiber interferometer using the light from an incoherent broadband source has been considered analytically and implemented as a laboratory device. It was shown that this optical scheme could be used to measure external perturbations that cause a change in the optical length of a multimode fiber. The use of an optical spectrum analyzer and correlation functions approach in extracting the utility signal made it possible to achieve a linear response to the measured external perturbation and effective fading mitigation. A pair of integral coefficients was introduced: the contrast coefficient for characterization of the coherency of the operation regime, and the fading coefficient for estimating the signal stability against non-signal parasitic influences. Analytical expressions for the utility signal parameters were derived in dependence on the parameters of the light source, multimode fiber, and optical spectrum analyzer. The relationships among fiber length, width of the light source spectrum, and frequency resolution of the optical spectrum analyzer were stated for the optimum regime of interferometer operation. The simulation of the external perturbations performed at the elaborated device proved the applicability of the proposed scheme as a sensor of various physical quantities.
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TL;DR: In this article, the inherent inhomogeneity of potential on the doped-semiconductor surface during the formation of equilibrium diffusion distribution for an electroactive impurity in the space-charge layers is discussed.
Abstract: The inherent inhomogeneity of potential on the doped-semiconductor surface during the formation of equilibrium diffusion distribution for an electroactive impurity in the space-charge layers is discussed. The characteristic random-potential values are determined in the case of nondegenerate surface electron gas. The dependence of these inhomogeneities on the surface and bulk parameters is shown.
8 citations
TL;DR: The localization behavior of a two-dimensional electron gas confined at the surface of a heavily doped semiconductor under conditions of the natural size effect in the space charge region is investigated in this article.
Abstract: The localization behavior of a two-dimensional electron gas confined at the surface of a heavily doped semiconductor under conditions of the “natural” size effect in the space-charge region is investigated. The scattering of low-energy electrons by the chaotic potential formed at the surface by point charges of ionized impurities is analyzed and the electron mean free path is determined. A criterion for strong localization in this two-dimensional electron system is obtained on the basis of the Ioffe–Regel criterion.
4 citations
TL;DR: In this paper, the concept of inherent dimensional effect in depleted semiconductor layers (comparability of the characteristic scale of a depleted layer to the average distance between electrically active defects) is introduced.
Abstract: The concept of an inherent dimensional effect in depleted semiconductor layers (comparability of the characteristic scale of a depleted layer to an average distance between electrically active defects) is introduced. Inherent nonuniformities of an electric field and the potential at the semiconductor surface are determined for intrinsic and impurity surface states. The dependence of these nonuniformities on surface and bulk parameters is considered.
4 citations