Cathodoluminescence and TEM investigations of structural and optical properties of AlGaN on epitaxial laterally overgrown AlN/sapphire templates

Surface steps as high as 15 nm on up to 10 μm thick AlN layers grown on patterned AlN/sapphire templates play a major role for the structural and optical properties of AlxGa1−xN layers with x ≥ 0.5 grown subsequently by metalorganic vapour phase epitaxy. The higher the Ga content in these layers is, the stronger is the influence of the surface morphology on their properties. For x = 0.5 not only periodic inhomogeneities in the Al content due to growth of Ga-rich facets are observed by cathodoluminescence, but these facets give rise to additional dislocation formation as discovered by annular dark-field scanning transmission electron microscopy. For AlxGa1−xN layers with x = 0.8 the difference in Al content between facets and surrounding material is much smaller. Therefore, the threading dislocation density (TDD) is only defined by the TDD in the underlying epitaxially laterally overgrown (ELO) AlN layer. This way high quality Al0.8Ga0.2N with a thickness up to 1.5 μm and a TDD ≤ 5x108 cm−2 was obtained

2D layered transport properties from topological insulator Bi2_2Se3_3 single crystals and micro flakes

Low-field magnetotransport measurements of topological insulators such as Bi$_2$Se$_3$ are important for revealing the nature of topological surface states by quantum corrections to the conductivity, such as weak-antilocalization. Recently, a rich variety of high-field magnetotransport properties in the regime of high electron densities ($\sim10^{19}$ cm$^{-3}$) were reported, which can be related to additional two-dimensional layered conductivity, hampering the identification of the topological surface states. Here, we report that quantum corrections to the electronic conduction are dominated by the surface states for a semiconducting case, which can be analyzed by the Hikami-Larkin-Nagaoka model for two coupled surfaces in the case of strong spin-orbit interaction. However, in the metallic-like case this analysis fails and additional two-dimensional contributions need to be accounted for. Shubnikov-de Haas oscillations and quantized Hall resistance prove as strong indications for the two-dimensional layered metallic behavior. Temperature-dependent magnetotransport properties of high-quality Bi$_2$Se$_3$ single crystalline exfoliated macro and micro flakes are combined with high resolution transmission electron microscopy and energy-dispersive x-ray spectroscopy, confirming the structure and stoichiometry. Angle-resolved photoemission spectroscopy proves a single-Dirac-cone surface state and a well-defined bulk band gap in topological insulating state. Spatially resolved core-level photoelectron microscopy demonstrates the surface stability.Comment: Sci. Rep. (2016

Improving the quality of alloys based on TiAl(gamma#) intermetallic compounds by flux treatment in the liquid state

Translated from Russian (Protsessy Lit'ya 1999 (4) p. 24-27)SIGLEAvailable from British Library Document Supply Centre-DSC:9023.190(10456)T / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Treatment of AL2 and AK7 silumins with low-temperature nitrogen plasma

Translated from Russian (Report of the Kiev Polytechnical Institute, Kiev (RU))Available from British Library Document Supply Centre-DSC:9023.19000(VR-Trans--8437)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Nitrogen permeability, diffusion coefficient and the solubility of nitrogen in liquid aluminium and Al-Si alloys

Translated from Russian (Protsessy Lit'ya 1997 (3) p. 24-33)SIGLEAvailable from British Library Document Supply Centre-DSC:9023.190(VR-Trans--8774)T / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Need for development of a state scientific-technical programme for cast dispersion-strengthened and composite materials

Translated from Russian (Report of Kiev Polytechnic Inst., Kiev, 1997)Available from British Library Document Supply Centre-DSC:9023.190(VR-Trans--8651)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

New aspects of production of titanium nitride for hardening aluminium alloys

Translated from Ukrainian (Protessy Lit'ya 1997 (1) p. 41-50)Available from British Library Document Supply Centre-DSC:9023.190(VR-Trans--8317)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Effect of the size of particles of the modifier on the process of nucleation of crystals of the solid phase from the melt

Translated from Ukrainian (Report of the Physical-Technological Inst. of Metals and Alloys, National Academy of Sciences of the Ukraine, Kiev (UA) 1997SIGLEAvailable from British Library Document Supply Centre-DSC:9023.19000(VR-Trans--8753)T / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Mass transfer of nitrogen in liquid alloys of aluminium with titanium and manganese

Translated from Russian (Protsessy Lit'ya 1999 (4) p. 11-15)Available from British Library Document Supply Centre-DSC:9023.190(10486)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo