Berlin 2012 – scientific programme

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O: Fachverband Oberflächenphysik

O 90: Metals and semiconductors: Epitaxy and growth

O 90.1: Talk

Friday, March 30, 2012, 10:30–10:45, A 060

Role of pulse control and material parameters on sub-monolayer pulsed-laser depositions — Martin Mašín and •Miroslav Kotrla — Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 182 21, Praha 8, Czech Republic

Pulsed laser depositions is the promising experimental method for nanostructuring of oxide, and also metallic thin films [1]. However, its theoretical understanding on the microscopic level is still insufficient. Recently, we performed Monte Carlo simulation motivated by a Fe/Mo system to analyze the temperature dependence of island density in the case of reversible growth [2]. In this work, we present our study of the dependence of the island density on varying characteristics of pulses: different chopping frequencies, and different duration of pulses. We also compare two regimes of pulse frequency variation: with a constant average flux and with a constant pulse intensity. In the former case, we found that low frequency increases the island density highlighting the recently found anomaly in the Arrhenius plot [2]. In the latter case, we observe, in contrary, that higher frequency leads to a higher island density. Increase of pulse length causes decrease of island density, leading to molecular beam epitaxy results. Moreover, we analyzed dependence on material parameters. The increase of a diffusion barrier for monomers shifts the whole Arrhenius curve to higher temperatures, and increase of binding energy moves a position of plateaus to higher temperatures. Our results allow to optimize pulse deposition.

[1] P. O. Jubert, O. Fruchart and C. Mayer, Phys. Rev. B , 64 (2001) 115419. [2] M. Mašín, M. Kotrla: Europhys. Lett. 90 (2010) 18006.