Multiphysics Modeling of Plasmonic Photoconductive Devices using Discontinuous Galerkin Methods
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Plasmonic nanostructures can significantly improve the performance of photoconductive devices (PCDs). In the mean time, they introduce intricate structures and complex scattering, which lead new challenges to simulations. In this work, a multiphysics framework based on discontinuous Galerkin (DG) methods is proposed to model the nonlinearly-coupled multiphysics processes in plasmonic PCDs. Without optical pumping, the nonequilibrium steady-state of the device, described by a coupled Poisson/drift-diffusion (DD) system, is solved with the Gummel iteration method. With pumping, the wave scattering, carrier dynamics and their nonlinear interactions are modeled by an explicit time domain solver solving the coupled system of Maxwell/time-dependent DD equations. The DD equations and Poisson equation are discretized with the local DG method and Maxwell equations are discretized with the nodal DG method. The DG-based multiphysics framework provides favorable discretization flexibilities for modeling the multiscale features in plasmonic PCDs. The proposed framework is demonstrated with simulations of a conventional PCD and a plasmonic PCD.
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