MBE of InGaN/GaN heterostructures using ammonia as a source of nitrogen

Technical Physics Letters - InGaN/GaN heterostructures have been grown by molecular beam epitaxy (MBE) using ammonia as a source of nitrogen. The influence of the growth temperature and rate on the...     

Optimization of the plastic relaxation of misfit stresses in Ge<Subscript>x</Subscript>Si<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>/Si(001) (<Emphasis Type="Italic">x</Emphasis>≤0.61) heterostructures

High-quality Ge_xSi_1−x /Si(001) (x=0.38–0.61) heterostructures (600–750 nm thick) with plastically relaxed mechanical stresses were grown by low-temperature molecular beam epitaxy. The total film thickness was reduced by using low-temperature growth and two-step variation of the Ge_xSi_1−x layer composition. High quality of the heterostructure is achieved due to the fact that misfit stresses between layers are released by dislocations passing from the first layer to the second.     

Geometry control of the junction between two fractal curves

The general objective of our work is to create a geometric modeller based on iterative processes. With this objective in mind, we have to provide tools that work with fractal objects in the same manner as with objects of classical topology. In this article we focus on the constructing of an intermediate curve between two other curves defined by different iterative construction processes. A similar problem often arises with subdivision surfaces, when the goal is to connect two surfaces with different subdivision masks. We start by dealing with curves, willing to later generalise our approach to surfaces. We formalise the problem with the Boundary Controlled Iterated Function System model. Then we deduct the conditions that guarantees continuity of the intermediate curve. These conditions determine the structure of subdivision matrices. By studying the eigenvalues of the subdivision operators, we characterise the differential behaviour at the connection points between the curves and the intermediate one. This behaviour depends on the nature of the initial curves and coefficients of the subdivision matrices. We also suggest a method to control the differential behaviour by adding intermediate control points.     

Local triboelectrification of an n-GaAs surface using the tip of an atomic-force microscope

The method of scanning Kelvin-probe microscopy is used to show that the effect of triboelectrification is observed when the tip of an atomic-force microscope interacts with the surface of n-GaAs epitaxial layers. The sign of the change in the potential indicates that the sample surface after triboelectrification becomes more negative. The observed specific features of the phenomena can be attributed to the thermally activated generation of point defects in the vicinity of the sample surface due to deformation caused by the tip.     

Trends in Reverse-Current Change in Tunnel MIS Diodes with Calcium Fluoride on Si(111) Upon the Formation of an Extra Oxide Layer

Semiconductors - The currents flowing in metal–CaF2–n-Si and metal–SiO2–CaF2–n-Si structures with the same (about 1.5 nm) fluoride thickness are compared in the...     

Solution of the problem of identifying structures of discrete stochastic objects based on the minimum posterior error criterion of distribution densities

The importance of studying methods for solving the problem of identifying structures of discrete stochastic objects has been shown. The general structure of an identification algorithm based on the use of generalized probabilistic criteria has been proposed. The structural identification algorithm is synthesized based on the minimum posterior error criterion of distribution densities. A numerical example that makes it possible to assess the effectiveness of the proposed approach has been considered.     

Non-linear S-box of Nyberg construction with maximal avalanche effect

The full class of irreducible polynomials f(z) of eight degree over all isomorphic representations of Galois field GF(256) is constructed. The set of optimal pairs {f(z), A}, where A is nonsingular affine transformation matrix is founded which allowed to increase significantly amount of Nyberg construction S-boxes, giving maximum avalanche effect.     

The calibration of gradient heat flux sensors

Test benches for calibrating heat flux sensors at temperatures of 500–1000 K are described, and the results of such calibrations are presented.