An exhaustive analysis of the frequency-dependent series resistance associated with the on-chip interconnects is presented. This analysis allows the identification of the regions where the resistance curves present different trending due to variations in the current distribution. Furthermore, it is explained the apparent discrepancy of experimental curves with the well-known square-root-of-frequency models for the resistance considering the skin-effect. Measurement results up to 40 GHz show that models involving terms proportional to the square root of frequency are valid provided that the section of the interconnect where the current is flowing is appropriately represented.

Structural, optical and luminescent properties of Si-rich HfO2 films fabricated by RF magnetron sputtering were investigated versus annealing treatment. Pronounced phase separation process occurred at 950-1100°C and resulted in the formation of hafnia and silica phases, as well as pure silicon clusters. An intense light emission of annealed samples in visible spectral range was obtained under broad band excitation. It was ascribed to exciton recombination inside silicon clusters as well as host defects. To confirm the formation of Si clusters, the structures were co-doped with Er3+ ions and effective light emission at 1.54µm was obtained under non-resonant excitation due to energy transfer from Si clusters towards Er3+ ions. The interaction of Si clusters, host defects and Er3+ ions under is discussed.

In this paper we present an ac-magneto-transport study of a two-dimensional electron gas (2DEG) in the quantum Hall effect (QHE) regime, for frequencies in the range [100Hz, 1MHz]. We present an approach to understand admittance measurements based in the Landauer-Buttiker formalism for QHE edge channels and taking into account the capacitance and the topology of the cables connected to the contacts used in the measurements. Our model predicts an universal behavior with the a-dimensional parameter RHCω where RH is the 2 wires resistance of the 2DEG, C the capacitance cables and the angular frequency, in agreement with experiments. For a specific configuration, we measure the electrochemical capacitance of the quantum Hall edge channels as predicted by Christen and Büttiker.