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Proceedings Paper

Conductive distributed Bragg reflector fabricated by oblique angle deposition from a single material
Author(s): Martin F. Schubert; Jong Kyu Kim; Sameer Chhajed; E. Fred Schubert
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Paper Abstract

Oblique angle deposition allows the fabrication of nano-structured porous thin films of high optical quality. By selecting the incident angle, the porosity - and thereby, the refractive index - of the deposited film can be tuned to a specific desired value. This makes it possible to fabricate multi-layer optical thin film components consisting entirely of a single material which is chosen for its properties other than refractive index, such as optical absorption or conductivity. As an application for this technique we demonstrate a conductive distributed Bragg reflector (DBR) designed for 460 nm. Common material choices in this wavelength range are SiO2 and TiO2; however, both materials are insulating. Conductive DBRs are limited to epitaxially grown doped semiconductors, which generally have low index contrast. The DBR reported here is composed entirely of indium tin oxide (ITO), chosen for its conductivity and low absorption. By varying the deposition angle a refractive index contrast of Δn = 0.4 is achieved, which yields a measured reflectivity of 72.7% for a three-period low-porosity-ITO/high-porosity-ITO DBR. The reflectivity is in excellent agreement with theory.

Paper Details

Date Published: 21 September 2007
PDF: 7 pages
Proc. SPIE 6674, Thin-Film Coatings for Optical Applications IV, 667403 (21 September 2007); doi: 10.1117/12.731266
Show Author Affiliations
Martin F. Schubert, Rensselaer Polytechnic Institute (United States)
Jong Kyu Kim, Rensselaer Polytechnic Institute (United States)
Sameer Chhajed, Rensselaer Polytechnic Institute (United States)
E. Fred Schubert, Rensselaer Polytechnic Institute (United States)

Published in SPIE Proceedings Vol. 6674:
Thin-Film Coatings for Optical Applications IV
Michael J. Ellison, Editor(s)

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