Surface plasmon resonance of gold and silver nanoparticle (NP) layers is investigated by the experiment as well as simulations. Although the good agreement was found for gold NP film, a significant mismatch in the resonance energy for silver NP film was observed. The deviation was assigned to the presence of silver oxide (${\text{Ag}}_2\mathrm{O}$ ) in silver NPs. As an alternative to the NP size-dependent Drude model, the analysis based on effective medium approximation for refractive index of ${\text{Ag}-\text{Ag}}_2\mathrm{O}$ material system is carried out and compared with the core-shell model. Both Mie's model and numerical simulation results illustrate shift of the surface plasmon resonance due to silver NP surface oxidation.

This paper introduces an advanced methodology for fast 3-D Technology Computer Aided Design (TCAD) electrothermal simulation for the analysis of power devices. The proposed methodology is based on coupling finite element method (FEM) thermal and circuit electrical simulation in a mixed-mode setup. A power InAlN/GaN high-electron mobility transistor (HEMT) is used to perform validation of the designed electrothermal simulation. A new equivalent temperature-dependent nonlinear analytical large signal circuit model of HEMT is proposed. The model is implemented to Synopsys TCAD Sentaurus using compact model interface. The designed electrothermal simulation methodology is developed to shorten the simulation time for complex 3-D devices. This approach combines the speed and accuracy, and couples temperature nonuniformity to the active device electrothermal behavior. The simulation results are compared with the measured data and results of 2-D FEM simulations. The features and limitations of the methods are analyzed and presented.