We present numerical calculations that support the existence of electronic states confined in the continuous part of the spectrum in single rectangular quantum wells and barriers. We study the conditions necessary for the creation of these states. We find strong energetic and spatial localization of quasi-bound states at high energies in the conduction band. The results can be used in the design of optoelectronic devices that operate on the basis of continuum bound states.

A ship building grade of carbon steel has been coated with copper by a furnace brazing process starting from a brass braze. An argon protective atmosphere was used to prevent oxidation of the steel. However, when the deposit was produced a low gas flow rate ensured that zinc was lost from the brass by oxidation leaving a copper deposit on the steel surface. The copper was found to be zinc free by Energy Dispersive X-ray spectroscopy. A metallographic study was carried out on the coated material and X-ray maps were used to identify the phases present in the coating. Diffusion was shown to play an important role in the development of the coating.An industrial application of this kind of coating could be applied in the heat exchanger due to the good thermal conductivity of copper.

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The oxide superconductor Y-Ba-Cu-O is studied using Auger scanning microscopy. The chemical depth profiles of the samples were obtained. It is concluded that two phases are present in the sample, one corresponding to the standard composition and another that is Ba enriched. The first shows a platelet shape and the second a granular appearence that covers the surface of the sample.

The lack of bandgap in graphene is the main factor that prevents that this outstanding material be implemented in optoelectronics. In this work, we show that by nanostructuring graphene aperiodically it is possible to have an efficient transmission bandgap engineering. In particular, we are considering aperiodic graphene superlattices in which electrostatic barriers are arranged following the basic construction rules of the Thue-Morse sequence. We find that the transmission bandgap can be modulated readily by changing the angle of incidence as well as by appropriately choosing the generation of the Thue-Morse superlattice. Even, this angle-dependent bandgap engineering is more effective than the corresponding one for periodic graphene superlattices.