Modeling and optimization of Au-GaAs plasmonic nanoslit array structures for enhanced near-infrared photodetector applications

Zachary T. Brawley; Stephen J. Bauman; Grant P. Abbey; Ahmad A. Darweesh; Ahmad I. Nusir; Omar Manasreh; Joseph Herzog

doi:10.1117/1.JNP.11.016017

23 March 2017 Modeling and optimization of Au-GaAs plasmonic nanoslit array structures for enhanced near-infrared photodetector applications

Zachary T. Brawley, Stephen J. Bauman, Grant P. Abbey, Ahmad A. Darweesh, Ahmad I. Nusir, Omar Manasreh, Joseph Herzog

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Journal of Nanophotonics, Vol. 11, Issue 1, 016017 (March 2017). https://doi.org/10.1117/1.JNP.11.016017

Abstract

This theoretical work explores how various geometries of Au plasmonic nanoslit array structures improve the total optical enhancement in GaAs photodetectors. Computational models studied these characteristics. Varying the electrode spacing, width, and thickness drastically affected the enhancement in the GaAs. Peaks in enhancement decayed as Au widths and thicknesses increased. These peaks are resonant with the incident near-infrared wavelength. The enhancement values were found to increase with decreasing electrode spacing. Additionally, a calculation was conducted for a model containing Ti between the Au and the GaAs to simulate the necessary adhesion layer. It was found that optical enhancement in the GaAs decreases for increasing Ti layer thickness. Optimal dimensions for the Au electrode include a width of 240 nm, thickness of 60 nm, electrode spacing of 5 nm, and a minimum Ti thickness. Optimal design has been shown to improve enhancement to values that are up to 25 times larger than for nonoptimized geometries and up to 300 times over structures with large electrode spacing. It was also found that the width of the metal in the array plays a more significant role in affecting the field enhancement than does the period of the array.

CC BY: © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Zachary T. Brawley, Stephen J. Bauman, Grant P. Abbey, Ahmad A. Darweesh, Ahmad I. Nusir, Omar Manasreh, and Joseph Herzog "Modeling and optimization of Au-GaAs plasmonic nanoslit array structures for enhanced near-infrared photodetector applications," Journal of Nanophotonics 11(1), 016017 (23 March 2017). https://doi.org/10.1117/1.JNP.11.016017

Received: 17 November 2016; Accepted: 13 March 2017; Published: 23 March 2017

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