Disentangling nonradiative recombination processes in Ge micro-crystals on Si substrates

Pezzoli, F. et al. (2016) Disentangling nonradiative recombination processes in Ge micro-crystals on Si substrates. Applied Physics Letters, 108, 262103. (doi:10.1063/1.4955020)

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Abstract

We address nonradiative recombination pathways by leveraging surface passivation and dislocation management in μm-scale arrays of Ge crystals grown on deeply patterned Si substrates. The time decay photoluminescence (PL) at cryogenic temperatures discloses carrier lifetimes approaching 45 ns in band-gap engineered Ge micro-crystals. This investigation provides compelling information about the competitive interplay between the radiative band-edge transitions and the trapping of carriers by dislocations and free surfaces. Furthermore, an in-depth analysis of the temperature dependence of the PL, combined with capacitance data and finite difference time domain modeling, demonstrates the effectiveness of GeO2 in passivating the surface of Ge and thus in enhancing the room temperature PL emission.

Item Type:Articles
Additional Information:Support from Fondazione Cariplo through Grant No. 2013-0623, the Sinergia project NOVIPIX CRSII2_147639 of the Swiss National Science Foundation.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Paul, Professor Douglas and Millar, Mr Ross and Gallacher, Dr Kevin
Authors: Pezzoli, F., Giorgioni, A., Gallacher, K., Isa, F., Biagioni, P., Millar, R. W., Gatti, E., Grilli, E., Bonera, E., Isella, G., Paul, D. J., and Miglio, L.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:Applied Physics Letters
Publisher:American Institute of Physics
ISSN:0003-6951
ISSN (Online):1077-3118
Published Online:28 June 2016
Copyright Holders:Copyright © 2016 AIP Publishing LLC
First Published:First published in Applied Physics Letters 108:262103
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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