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Reduced Photoconductivity Observed by Time-Resolved Terahertz Spectroscopy in Metal Nanofilms with and without Adhesion Layers

Published

Author(s)

Brian Alberding, Edwin J. Heilweil, Gary P. Kushto, Paul A. Lane

Abstract

Time-resolved terahertz spectroscopy (TRTS) has been used to study the transient photoconductivity of nanometer-scale metallic films deposited on fused quartz substrates. Samples of 8 nm thick gold or titanium show an instrument-limited decrease in conductivity following photoexcitation due to electron-phonon coupling and increased lattice temperatures which increases charge carrier scattering. In contrast, for samples of 8 nm gold with a 4 nm adhesion layer of titanium or chromium, a ca. 70 ps rise time for the lattice temperature increase is observed. These results establish the increased transient terahertz transmission sign change of metallic compared to semiconductor materials. The results also suggest nanoscale gold films that utilize an adhesion material do not consist of distinct layers.
Citation
Applied Physics Letters
Volume
108

Keywords

Metal nanofilm, gold, chromium, titanium, Time-resolved Terahertz Spectroscopy, electron-phonon coupling, carrier dynamics, alloy, adhesion layer

Citation

Alberding, B. , Heilweil, E. , Kushto, G. and Lane, P. (2016), Reduced Photoconductivity Observed by Time-Resolved Terahertz Spectroscopy in Metal Nanofilms with and without Adhesion Layers, Applied Physics Letters, [online], https://doi.org/10.1063/1.4953208, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=920421 (Accessed April 18, 2024)
Created May 28, 2016, Updated October 12, 2021