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Energy Express

Energy Express

  • Editor: Bernard Kippelen
  • Vol. 20, Iss. S4 — Jul. 2, 2012
  • pp: A441–A451

THz conductivities of indium-tin-oxide nanowhiskers as a graded-refractive-index structure

Chan-Shan Yang, Chia-Hua Chang, Mao-Hsiang Lin, Peichen Yu, Osamu Wada, and Ci-Ling Pan  »View Author Affiliations

Optics Express, Vol. 20, Issue S4, pp. A441-A451 (2012)

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Indium-tin-oxide (ITO) nanowhiskers with attractive electrical and anti-reflection properties were prepared by the glancing-angle electron-beam evaporation technique. Structural and crystalline properties of such nanostructures were examined by scanning transmission electron microscopy and X-ray diffraction. Their frequency-dependent complex conductivities, refractive indices and absorption coefficients have been characterized with terahertz time-domain spectroscopy (THz-TDS), in which the nanowhiskers were considered as a graded-refractive-index (GRIN) structure instead of the usual thin film model. The electrical properties of ITO GRIN structures are analyzed and fitted well with Drude-Smith model in the 0.2~2.0 THz band. Our results indicate that the ITO nanowhiskers and its bottom layer atop the substrate exhibit longer carrier scattering times than ITO thin films. This signifies that ITO nanowhiskers have an excellent crystallinity with large grain size, consistent with X-ray data. Besides, we show a strong backscattering effect and fully carrier localization in the ITO nanowhiskers.

© 2012 OSA

OCIS Codes
(120.4290) Instrumentation, measurement, and metrology : Nondestructive testing
(120.4530) Instrumentation, measurement, and metrology : Optical constants
(290.1350) Scattering : Backscattering
(300.6270) Spectroscopy : Spectroscopy, far infrared
(260.2065) Physical optics : Effective medium theory
(040.2235) Detectors : Far infrared or terahertz
(160.4236) Materials : Nanomaterials
(220.4241) Optical design and fabrication : Nanostructure fabrication
(300.6495) Spectroscopy : Spectroscopy, teraherz

ToC Category:

Original Manuscript: March 23, 2012
Revised Manuscript: April 25, 2012
Manuscript Accepted: April 30, 2012
Published: May 10, 2012

Chan-Shan Yang, Chia-Hua Chang, Mao-Hsiang Lin, Peichen Yu, Osamu Wada, and Ci-Ling Pan, "THz conductivities of indium-tin-oxide nanowhiskers as a graded-refractive-index structure," Opt. Express 20, A441-A451 (2012)

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