Reduced photoconductivity observed by time-resolved terahertz spectroscopy in metal nanofilms with and without adhesion layers
- Optical Sciences Division, US Naval Research Laboratory, Washington, DC 20375 (United States)
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.
- OSTI ID:
- 22590739
- Journal Information:
- Applied Physics Letters, Vol. 108, Issue 22; Other Information: (c) 2016 U.S. Government; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
Similar Records
Photoinduced Charge Carrier Generation in a Poly(3-hexylthiophene) and Methanofullerene Bulk Heterojunction Investigated by Time-Resolved Terahertz Spectroscopy
Applicability of the thin-film approximation in terahertz photoconductivity measurements