Polarization of photoluminescence excitation and emission spectra of silicon nanorods within single Si/SiO2 nanowires
2011 (English)In: Physica Status Solidi. C, Current topics in solid state physics, ISSN 1610-1634, E-ISSN 1610-1642, Vol. 8, no 3, 1017-1020 p.Article in journal (Refereed) Published
Polarization properties of individual silicon nanowires are studied using an optical micro-spectroscopy setup equipped with a Fresnel rhomb to rotate the polarization of the exciting laser and the analyzer to characterize the polarization of emitted photoluminescence. The Si nanowire samples are prepared by electron-beam lithography, plasma etching and oxidation. The fabricated wires are embedded in SiO2 and oriented parallel to the Si substrate. Due to the fluctuating wire diameter (around 5 nm) the very long wires (several tens of μm) are effectively divided into an array of quantum rods (prolate ellipsoids). These structures have strong photoluminescence under UV-blue excitation at room temperature. The degree of photoluminescence linear polarization of both excitation and emission is very high, between 0.9-1, and reveals relatively low fluctuations at different spots of the wires. Experimental results are compared with available theoretical models leading to the conclusion that the high polarization degree is mostly due to surface charges (dielectric confinement) with smaller contribution of quantum confinement effects.
Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2011. Vol. 8, no 3, 1017-1020 p.
Luminescence, Nanorod, Nanowire, Polarization, Silicon
IdentifiersURN: urn:nbn:se:kth:diva-49809DOI: 10.1002/pssc.201000398ISI: 000301537100087ScopusID: 2-s2.0-79952675785OAI: oai:DiVA.org:kth-49809DiVA: diva2:460344
QC 201111302012-03-212011-11-292012-09-20Bibliographically approved