Regensburg 2016 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 26: Poster session II
MM 26.35: Poster
Dienstag, 8. März 2016, 18:30–20:30, Poster B3
The formation of nc-Si in SiOx induced by continuous-wave laser irradiation — •Nan Wang1, Thomas Fricke-Begemann2, Patrick Peretzki1, Michael Seibt1, and Jürgen Ihlemann2 — 1IV. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany — 2Laser-Laboratorium Göttingen, Hans-Adolf-Krebs-Weg 1, 37077 Göttingen, Germany
Silicon nanocrystals embedded in substoichiometric SiOx (silicon-rich silicon oxide) exhibit room-temperature photoluminescence due to quantum confinements. The generation of nc-Si can be induced by thermal annealing or laser irradiation. It is known that laser irradiation on free-standing SiOx without substrate may avoid the heat flow into the substrate. Here we employ continuous-wave laser irradiation at 405 nm wavelength to focus a 6 µm diameter spot on 545 nm thick SiOx films deposited on fused silica substrates. A high density of nc-Si particles is obtained. The samples are characterized by AFM, TEM, Raman spectroscopy and photoluminescence. The spatial distribution of the nanocrystals in the irradiated area is determined. At a laser irradiance of 1.2·105 W/cm2, an almost perfect damage-free irradiation is obtained. At higher laser power the central region exhibits some porous properties, and the nc-Si region is located beneath the porous region. In summary, we have demonstrated that laser annealing offers the possibility to generate Si nanoparticles in a fast, high throughput process. Also, the thermal load on the substrate can be significantly reduced.