Regensburg 2010 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 36: Ge, GeSi, and Si

HL 36.10: Talk

Wednesday, March 24, 2010, 12:00–12:15, H14

Influence of oxide layer thickness on thermal properties of single silicon nanowires: a Raman study — •Asmus Vierck, Sevak Khachadorian, Janina Maultzsch, and Christian Thomsen — Institut für Festkörperphysik, TU-Berlin, EW 5-4, Hardenbergstr. 36, 10623 Berlin, Germany

The Raman spectra of single silicon nanowires (SiNWs) varying SiO₂ layer thickness were studied as a function of laser excitation power using combined atomic force microscopy (AFM) and Raman spectroscopy. Since silicon nanowires grown by chemical vapour deposition (CVD) are inevitably oxidized during fabrication, a modification in shape and size of the crystalline core can be observed, dependent on oxidation time. To determine the impact of different oxide shells on the silicon core properties, we used Raman spectroscopy to study possible alterations in phonon confinement of samples oxidized for different durations. By separating the SiNWs from their original silicon substrate, we were able to compare the spectra of single NWs with distinct width, determined by AFM. While varying the incident laser power we investigated the downshift of the transverse optical phonon in different oxidized NWs as compared to that of bulk silicon.