Open AccessEncapsulation of low-refractive-index SiO_2 nanorods by Al_2O_3 with atomic layer deposition
Author(s) -
Sangho S. Kim,
Nicholas T. Gabriel,
Woo Bin Song,
Joseph J. Talghader
Publication year - 2007
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.15.016285
Subject(s) - refractive index , atomic layer deposition , materials science , nanoporous , nanorod , thin film , distributed bragg reflector , thermal stability , high refractive index polymer , porosity , thermal expansion , optics , optoelectronics , nanotechnology , composite material , chemical engineering , wavelength , physics , engineering
Thin films composed of SiO(2) nanorods or nanoporous SiO(2) (np- SiO(2)) 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-SiO(2) can be encapsulated by depositing Al(2)O(3) 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.