Applied Physics A

, Volume 106, Issue 4, pp 853–861

Photothermal laser processing of thin silicon nanoparticle films: on the impact of oxide formation on film morphology

  • Dennis Behrenberg
  • Steffen Franzka
  • Nils Petermann
  • Hartmut Wiggers
  • Nils Hartmann
Article

DOI: 10.1007/s00339-012-6779-8

Cite this article as:
Behrenberg, D., Franzka, S., Petermann, N. et al. Appl. Phys. A (2012) 106: 853. doi:10.1007/s00339-012-6779-8

Abstract

Photothermal laser processing of thin films of H-terminated silicon nanoparticles (Si NPs) is investigated. Ethanolic dispersions of Si NPs with an average diameter of 45 nm are spin-coated on silicon substrates yielding films with thicknesses ≤500 nm. Small-area laser processing is carried out using a microfocused scanning cw-laser setup operating at a wavelength of 532 nm and a 1/e laser spot size of 1.4 μm. In conjunction with microscopic techniques, this provides a highly reproducible and convenient approach in order to study the dependence of the resulting film morphology and composition on the experimental parameters. Processing in air results in strongly oxidized granular structures with sizes between 100 and 200 nm. The formation of these structures is dominated by surface oxidation. In particular, changing the processing parameters (i.e., laser power, writing speed, and/or the background air pressure) has little effect on the morphology. Only in vacuum at pressures <1 mbar, oxygen adsorption, and hence oxide formation, is largely suppressed. Under these conditions, irradiation at low laser powers results in mesoporous surface layers, whereas compact silicon films are formed at high laser powers. In agreement with these results, comparative experiments with films of H-terminated and surface-oxidized Si NPs reveal a strong impact of the surface oxide layer on the film morphology. Mechanistic aspects and implications for photothermal processing techniques, e.g., targeting photovoltaic and thermoelectric applications, are discussed.

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Dennis Behrenberg
    • 1
    • 3
  • Steffen Franzka
    • 1
    • 3
  • Nils Petermann
    • 2
    • 3
  • Hartmut Wiggers
    • 2
    • 3
  • Nils Hartmann
    • 1
    • 3
  1. 1.Fakultät für ChemieUniversität Duisburg-EssenEssenGermany
  2. 2.Institut für Verbrennung und Gasdynamik (IVG)Universität Duisburg-EssenDuisburgGermany
  3. 3.Center for Nanointegration Duisburg-Essen (CENIDE)Universität Duisburg-EssenDuisburgGermany