Regensburg 2004 – scientific programme

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DS: Dünne Schichten

DS 14: Schichtwachstum

DS 14.7: Talk

Wednesday, March 10, 2004, 16:00–16:15, HS 32

Porous Thin Films Grown by Size-Selected Si-Nanoparticles — •Felix Voigt¹, Rudolf Brüggemann¹, Friedrich Huisken² und Gottfried H. Bauer¹ — ¹Fakultät V, Institut für Physik, CvO-Universität Oldenburg, 26111 Oldenburg — ²Laborastrophysik-Gruppe, Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, 07743 Jena

Size selected Si-nanoparticles (Si-nc) with diameters ≥ 3 nm prepared in a flow reactor with CO₂ laser induced SiH₄ decomposition and showing strong luminescence in the visible regime after oxidation of their surface [1] have been accumulated as thin films on different substrates. These films contain clusters of conglomerated Si-nc which conserve the electronic properties of the single Si-nc such as the compression of electronic wave functions which has been verified by spectral pl-measurements. The degree of volume filling has been analyzed experimentally to about 0.3. This number is supported by a simplified numerical stick-ball model for the local arrangement of the Si-nc versus film growth time. We have studied the growth of these porous thin films by simultaneous coplanar charge transport measurements (interdigital metal contacts) and see three regimes: i) negligible transport at the beginning of film growth due to missing connections, ii) a superlinear increase of current with exponent 3/2 which will be discussed in terms of percolation transport, and iii) a linear increase with further film thickness. [1] G. Ledoux, O. Guillois, D. Porterat, C. Reynaud, F. Huisken, B. Kohn, V. Paillard, Phys. Rev. B. 62, 15 942 (2000).