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Two-dimensional photon echo spectroscopy allows one to track relaxation and correlation processes in optically excited nanostructures. We analyze such spectra for intersubband transitions in an n-doped GaAs/Al 0.35 Ga 0.65 As single quantum well. Focusing on electron-longitudinal optical phonon interaction in a non-Markovian treatment, the carrier dynamics in the conduction subbands are investigated in the low density regime. Our results provide detailed information about the temporal evolution of electron-phonon correlations in the two-dimensional frequency spectrum.

This paper presents a finite element based simulation methodology to improve on multiscale modeling and analysis limitations of power electronics development. The method utilizes homogenization and non-matching grid concepts to offer a high degree of flexibility and reduce computational effort. The applied homogenization method provides effective material properties to realize full chip modeling performance without the need to model geometric details. The concept of non-matching grids allows the inclusion of a sub-region with substantially finer mesh than its surrounding regions. This allows the flexible integration of micrometer scale geometries with a high degree of detail within the full chip model. Both concepts are thoroughly introduced and an application to a state-of-the-art power electronics semiconductor technology is presented. This work focus on electrothermal interaction and is experimentally verified on a dedicated test structure. The presented results provide electrothermal insights in current power electronic technologies and emphasize their potential to further improve the robustness and reliability of next generation technologies.Index Terms-power semiconductor devices, heat transfer, electrothermal effects, thermal characterization, finite element methods, multiscale modeling 0885-8993 (c)

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