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K: Fachverband Kurzzeitphysik

K 5: Laserstrahlwechselwirkung und Laseranwendungen

K 5.8: Talk

Tuesday, February 26, 2013, 15:45–16:00, HS 4

Atomistic-continuum modeling of short pulse laser melting of semiconductors — •Vladimir Lipp^1,2, Dmitry Ivanov^1,2, Martin Garcia², and Baerbel Rethfeld¹ — ¹Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany — ²University of Kassel, 34132 Kassel, Germany

A combined atomistic-continuum computational technique for the description of the melting kinetics following short laser-pulse excitation of semiconductors is developed and applied to silicon. The method is based on the coupling of two different approaches: (i) the continuum model [1], which describes the laser light absorption, electron-phonon nonequilibrium and fast heat transport due to free carriers, and (ii) the molecular dynamics method, which accounts for the description of laser-induced nonequilibrium phase transition processes at atomic level. The combined model presented here unifies the advantages of both mentioned approaches [2] and allows a comprehensive study of the material behavior under the extreme conditions generated by ultrashort laser irradiation. Preliminary results on depth of laser-induced melting obtained with the combined model show good agreement with experiment. A recently developed new potential accounting for changes of the bonding state due to photo-excited free carriers [3] is a promising tool for the introduction of nonthermal processes in the description of silicon kinetics under strong nonequilibrium conditions. [1]. H.M. van Driel, Phys. Rev. B 35 (1987) 8166-8176. [2]. Dmitriy S. Ivanov and Leonid V. Zhigilei, Phys. Rev. B 68, 064114 (2003). [3]. Lalit Shokeen and Patrick K. Schelling, J. Appl. Phys. 109, 073503 (2011).