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Title: Reduced photoconductivity observed by time-resolved terahertz spectroscopy in metal nanofilms with and without adhesion layers

Abstract

Non-contact, optical time-resolved terahertz spectroscopy has been used to study the transient photoconductivity of nanometer-scale metallic films deposited on the fused quartz substrates. Samples of 8 nm thick gold or titanium show an instrument-limited (ca. 0.5 ps) decrease in conductivity following photoexcitation due to electron-phonon coupling and subsequent 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.

Authors:
; ;  [1]
  1. Optical Sciences Division, US Naval Research Laboratory, Washington, DC 20375 (United States)
Publication Date:
OSTI Identifier:
22590739
Resource Type:
Journal Article
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 108; Journal Issue: 22; Other Information: (c) 2016 U.S. Government; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0003-6951
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ADHESION; CHARGE CARRIERS; CHROMIUM; DEPOSITS; ELECTRON-PHONON COUPLING; FILMS; GOLD; LAYERS; NANOSTRUCTURES; PHONONS; PHOTOCONDUCTIVITY; PULSE RISE TIME; QUARTZ; SCATTERING; SEMICONDUCTOR MATERIALS; SPECTROSCOPY; SUBSTRATES; TIME RESOLUTION; TITANIUM

Citation Formats

Alberding, Brian G., Heilweil, Edwin J., E-mail: edwin.heilweil@nist.gov, Kushto, Gary P., and Lane, Paul A. Reduced photoconductivity observed by time-resolved terahertz spectroscopy in metal nanofilms with and without adhesion layers. United States: N. p., 2016. Web. doi:10.1063/1.4953208.
Alberding, Brian G., Heilweil, Edwin J., E-mail: edwin.heilweil@nist.gov, Kushto, Gary P., & Lane, Paul A. Reduced photoconductivity observed by time-resolved terahertz spectroscopy in metal nanofilms with and without adhesion layers. United States. https://doi.org/10.1063/1.4953208
Alberding, Brian G., Heilweil, Edwin J., E-mail: edwin.heilweil@nist.gov, Kushto, Gary P., and Lane, Paul A. 2016. "Reduced photoconductivity observed by time-resolved terahertz spectroscopy in metal nanofilms with and without adhesion layers". United States. https://doi.org/10.1063/1.4953208.
@article{osti_22590739,
title = {Reduced photoconductivity observed by time-resolved terahertz spectroscopy in metal nanofilms with and without adhesion layers},
author = {Alberding, Brian G. and Heilweil, Edwin J., E-mail: edwin.heilweil@nist.gov and Kushto, Gary P. and Lane, Paul A.},
abstractNote = {Non-contact, optical time-resolved terahertz spectroscopy has been used to study the transient photoconductivity of nanometer-scale metallic films deposited on the fused quartz substrates. Samples of 8 nm thick gold or titanium show an instrument-limited (ca. 0.5 ps) decrease in conductivity following photoexcitation due to electron-phonon coupling and subsequent 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.},
doi = {10.1063/1.4953208},
url = {https://www.osti.gov/biblio/22590739}, journal = {Applied Physics Letters},
issn = {0003-6951},
number = 22,
volume = 108,
place = {United States},
year = {Mon May 30 00:00:00 EDT 2016},
month = {Mon May 30 00:00:00 EDT 2016}
}