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Light-induced reflectivity transients in black-Si nanoneedles

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posted on 2024-08-06, 09:38 authored by P. Ščajev, T. Malinauskas, G. Seniutinas, M. D. Arnold, A. Gentle, I. Aharonovich, G. Gervinskas, P. Michaux, J. S. Hartley, E. L.H. Mayes, Paul StoddartPaul Stoddart, Saulius JuodkazisSaulius Juodkazis
The change in reflectivity of black-Si (b-Si) upon optical excitation was measured by the pump-probe technique using picosecond laser pulses at 532 (pump) and 1064 nm (probe) wavelengths. The specular reflection from the random pattern of plasma-etched b-Si nano-needles was dominated by the photo-excited free-carrier contribution to the reflectivity. The kinetics of the reflectivity were found to be consistent with surface structural and chemical analysis, performed by scanning and transmission electron microscopy, and spectroscopic ellipsometry. The surface recombination velocity on the b-Si needles was estimated to be ~102cm/s. Metalization of b-Si led to much faster recombination and alteration of reflectivity. The reflectivity spectra of random b-Si surfaces with different needle lengths was modeled by a multi-step refractive index profile in the Drude formalism. The dip in the reflectivity spectra and the sign reversal in the differential reflectivity signal at certain b-Si needle sizes is explained by the model.

Funding

Photonic crystals at visible wavelengths

Australian Research Council

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Fabrication strategies for nanophotonic devices

Australian Research Council

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New generation nanostructured coatings with combined control of spectral and angular emissivity

Australian Research Council

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History

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PDF (Accepted manuscript)

ISSN

0927-0248

Journal title

Solar Energy Materials and Solar Cells

Volume

144

Issue

14

Pagination

6 pp

Publisher

Elsevier

Copyright statement

Copyright © 2015 Elsevier B.V. All rights reserved. NOTICE: this is the author’s version of a work that was accepted for publication in Solar Energy Materials and Solar Cells resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Solar Energy Materials and Solar Cells, Vol. 144, (Jan 2016), pp. 221-227 (DOI:10.1016/j.solmat.2015.08.030).

Language

eng

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