Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 10: Preparation and characterization
HL 10.2: Vortrag
Montag, 25. Februar 2008, 09:45–10:00, EW 202
Application of evolutionary strategies to the analysis of defects in semiconductors — •Silvia Schumann1 and Torsten Hahn2 — 1TU Bergakademie Freiberg, Institute for Theoretical Physics, Leipziger Str. 23, 09599 Freiberg, Germany — 2TU Bergakademie Freiberg, Institute for Experimental Physics, Leipziger Str. 23, 09599 Freiberg, Germany
This work presents an application of evolutionary strategies to the analysis of defects in semiconductors. Experimental Photo-Induced Current Transient Spectroscopy (PICTS) measurements have been simulated at different levels of optical excitation. These simulations give access to various physical properties like e.g. the minority carrier lifetimes. This enables us to compare directly the simulated data to quasi steady state photoconductance and PICTS-measurements at different injection levels. The evolutionary strategy was chosen because of the high dimension of the problem and the unknown landscape of the objective function. The application of the evolutionary algorithm provides the defect configurations, where each defect is characterized by its energy, concentration, and capture cross-section. Suitable configurations in very good agreement with experimental data can be obtained already after a few generations. The evolutionary algorithm avoids trapping in local minima and provides information on the range of possible solutions.