Encapsulation of low-refractive-index SiO2 nanorods by Al 2O3 with atomic layer deposition

Sangho S. Kim, Nicholas T. Gabriel, Woo Bin Song, Joseph J. Talghader

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Thin films composed of SiO2 nanorods or nanoporous SiO 2 (npSiO2) are attractive for use as a low refractive index material in various types of optical coatings. However, the material properties of these films are unstable because of the high porosity of the films. This is particularly apparent in dry versus humid atmospheres where both the refractive index and coefficient of thermal expansion (CTE) vary dramatically. In this article, we demonstrate that np-SiO2 can be encapsulated by depositing Al2O3 with Atomic Layer Deposition (ALD), stabilizing these properties. In addition, this encapsulation ability is demonstrated successfully in a 4-pair distributed Bragg reflector (DBR) design. It is hoped that this technique will be useful in patterning specific regions of a film for optical and mechanical stability while other portions are ambient-interactive for sensing.

Original languageEnglish (US)
Pages (from-to)16285-16291
Number of pages7
JournalOptics Express
Issue number24
StatePublished - Nov 26 2007


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