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K: Kurzzeitphysik

K 6: Short time-scale physics, posters

K 6.4: Poster

Donnerstag, 5. April 2001, 12:30–14:30, AT2

Microscopic characterization of ablation craters on semiconductors > produced by femtosecond laser pulses — •Vasily V. Temnov^1,2, Nikola Stojanovic¹, Sergei Kudryashov^1,3, Klaus Sokolowski-Tinten¹, Dietrich von der Linde¹, Boris Kogan¹, Andreas Schlarb¹, Bastian Weyers¹, Rolf Möller¹, and Michael Horn von Hoegen¹ — ¹Institut für Laser- und Plasmaphysik, Universität > Essen, > D-45117 Essen, Germany — ²Institute of Applied Physics, 603600 Nizhny Novgorod, Ulyanova > St. 46, Russia — ³Chemistry Department, Moscow State University, 119899 Moscow, > Russia

> The formation of well defined craters is a general feature of > laser ablation with ultrashort laser pulses. Using four different > microscopic techniques (optical differential interference contrast > (DIC) and interference microscopy, scanning electron (SEM) and > atomic force microscopy (AFM)), we have performed a comprehensive > experimental study of the morphology of semiconductor surfaces > after irradiation with intense femtosecond laser pulses. The > produced craters possess very sharp boundaries, indicative of a > well defined ablation threshold, with a characteristic structure > on a sub-micron scale. The crater depth after single pulse > irradiation is typically a few tens of nanometers with only weak > dependence on the laser fluence. We also studied the surface > structure inside and outside the crater, and compared craters of > different sizes produced under different focusing conditions > (large and small focal lengths). >