Observation of strongly enhanced photoluminescence from inverted cone-shaped silicon nanostructures

Schmitt SW, Sarau G, Christiansen S (2015)

Publication Type: Journal article

Publication year: 2015

Journal

Scientific Reports Nature Publishing Group: Open Access Journals - Option B

Book Volume: 5

Article Number: 17089

DOI: 10.1038/srep17089

Abstract

Silicon nanowires (SiNWs) attached to a wafer substrate are converted to inversely tapered silicon nanocones (SiNCs). After excitation with visible light, individual SiNCs show a 200-fold enhanced integral band-to-band luminescence as compared to a straight SiNW reference. Furthermore, the reverse taper is responsible for multifold emission peaks in addition to the relatively broad near-infrared (NIR) luminescence spectrum. A thorough numerical mode analysis reveals that unlike a SiNW the inverted SiNC sustains a multitude of leaky whispering gallery modes. The modes are unique to this geometry and they are characterized by a relatively high quality factor (Q ~ 1300) and a low mode volume (0.2 < (\textgreekl/neff)3 < 4). In addition they show a vertical out coupling of the optically excited NIR luminescence with a numerical aperture as low as 0.22. Estimated Purcell factors Fp $∝$ Q/Vm of these modes can explain the enhanced luminescence in individual emission peaks as compared to the SiNW reference. Investigating the relation between the SiNC geometry and the mode formation leads to simple design rules that permit to control the number and wavelength of the hosted modes and therefore the luminescent emission peaks.

Additional Organisation(s)

Exzellenz-Cluster Engineering of Advanced Materials

Involved external institutions

Max-Planck-Institut für die Physik des Lichts (MPL) / Max Planck Institute for the Science of Light DE Germany (DE) Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) DE Germany (DE)

How to cite

APA:

Schmitt, S.W., Sarau, G., & Christiansen, S. (2015). Observation of strongly enhanced photoluminescence from inverted cone-shaped silicon nanostructures. Scientific Reports, 5. https://dx.doi.org/10.1038/srep17089

MLA:

Schmitt, Sebastian W., George Sarau, and Silke Christiansen. "Observation of strongly enhanced photoluminescence from inverted cone-shaped silicon nanostructures." Scientific Reports 5 (2015).

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