Nonlinear electronic transport and enhanced catalytic behavior caused by native oxides on Cu nanowires

Abstract Electrical transport properties of individual nanowires (both in axial and transversal directions) and their random networks suggest rapid oxidation when Cu is exposed to ambient conditions. The oxidation process is elucidated by thorough XRD, XPS and Raman analyzes conducted for a period of 30 days. Based on the obtained experimental data, we may conclude that first, cuprous oxide and copper hydroxide form that finally transform to cupric oxide. In electrical applications, oxidation of copper is not a true problem as long as thin films or bulk metal is concerned. However, as highlighted in our work, this is not the case for nanowires, since the oxidized surface plays quite important role in the contact formation and also in the conduction of percolated nanowire networks. On the other hand, by taking advantage of the mixed surface oxide states present on the nanowires along with their large specific surface area, we tested and found excellent catalytic activity of the oxidized nanowires in phenol oxidation, which suggests further applications of these materials in catalysis

Characterisation of RF connectors and components for advanced 5G applications

Abstract Development of 5G and beyond technologies brings wireless communications systems to operate at higher frequencies and makes them more compact and integrated in nature. This places further challenges for component and system design, but at the same time the need for reliable RF interconnections becomes more and more important. This work investigates passive RF structures implemented on a low-permittivity Panasonic dielectric substrate up to a frequency of 110 GHz with simulations and measurements. Two different test cases are considered: a simple transmission line with a TRL calibration structure as well as a Wilkinson power divider. Agreement between simulations and measurements is rather good, and the results show that the used substrate material is a viable alternative for RF applications around 100 GHz