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Formation of broadband antireflective and superhydrophilic subwavelength structures on fused silica using one-step self-masking reactive ion etching.

Ye X, Jiang X, Huang J, Geng F, Sun L, Zu X, Wu W, Zheng W - Sci Rep (2015)

Bottom Line: The measured antireflection properties are consistent with the results of theoretical analysis using a finite-difference time-domain (FDTD) method.This method is also applicable to diffraction grating fabrication.Moreover, the surface of the subwavelength structures exhibits significant superhydrophilic properties.

View Article: PubMed Central - PubMed

Affiliation: Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang, 621900 (P.R. China).

ABSTRACT
Fused silica subwavelength structures (SWSs) with an average period of ~100 nm were fabricated using an efficient approach based on one-step self-masking reactive ion etching. The subwavelength structures exhibited excellent broadband antireflection properties from the ultraviolet to near-infrared wavelength range. These properties are attributable to the graded refractive index for the transition from air to the fused silica substrate that is produced by the ideal nanocone subwavelength structures. The transmittance in the 400-700 nm range increased from approximately 93% for the polished fused silica to greater than 99% for the subwavelength structure layer on fused silica. Achieving broadband antireflection in the visible and near-infrared wavelength range by appropriate matching of the SWS heights on the front and back sides of the fused silica is a novel strategy. The measured antireflection properties are consistent with the results of theoretical analysis using a finite-difference time-domain (FDTD) method. This method is also applicable to diffraction grating fabrication. Moreover, the surface of the subwavelength structures exhibits significant superhydrophilic properties.

No MeSH data available.


Schematic illustration of the SWS preparation process.
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f1: Schematic illustration of the SWS preparation process.

Mentions: Polymer nanodots formed on the substrate surface during the RIE process under certain plasma conditions. These polymer nanodots can be considered random micro-etch masks on the fused silica surface (Fig. 1A). A fused silica cone-like profile with the polymer nanodot tips was formed using reactive radical etching of the substrate surface (Fig. 1B). The polymer nanodots were etched during the RIE process, but the etching speed was much slower than the fused silica. In addition, polymers were deposited on the surface throughout the etching process. The surface peaks received more deposited polymer than the valleys. Furthermore, the polymer nanodots formed on the nanocone tips induced greater polymer deposition. Therefore, the height of the fused silica nanocones could be controlled by altering the etching conditions. Owing to isotropic etching during the RIE process, tapered sidewalls of the silica SWS formed on the fused silica substrate. Random fused silica SWSs with a tapered profile and high aspect ratio were obtained, as shown schematically in Fig. 1. The samples were then cleaned using O2 plasma for 5 min to remove the polymer residue.


Formation of broadband antireflective and superhydrophilic subwavelength structures on fused silica using one-step self-masking reactive ion etching.

Ye X, Jiang X, Huang J, Geng F, Sun L, Zu X, Wu W, Zheng W - Sci Rep (2015)

Schematic illustration of the SWS preparation process.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4542686&req=5

f1: Schematic illustration of the SWS preparation process.
Mentions: Polymer nanodots formed on the substrate surface during the RIE process under certain plasma conditions. These polymer nanodots can be considered random micro-etch masks on the fused silica surface (Fig. 1A). A fused silica cone-like profile with the polymer nanodot tips was formed using reactive radical etching of the substrate surface (Fig. 1B). The polymer nanodots were etched during the RIE process, but the etching speed was much slower than the fused silica. In addition, polymers were deposited on the surface throughout the etching process. The surface peaks received more deposited polymer than the valleys. Furthermore, the polymer nanodots formed on the nanocone tips induced greater polymer deposition. Therefore, the height of the fused silica nanocones could be controlled by altering the etching conditions. Owing to isotropic etching during the RIE process, tapered sidewalls of the silica SWS formed on the fused silica substrate. Random fused silica SWSs with a tapered profile and high aspect ratio were obtained, as shown schematically in Fig. 1. The samples were then cleaned using O2 plasma for 5 min to remove the polymer residue.

Bottom Line: The measured antireflection properties are consistent with the results of theoretical analysis using a finite-difference time-domain (FDTD) method.This method is also applicable to diffraction grating fabrication.Moreover, the surface of the subwavelength structures exhibits significant superhydrophilic properties.

View Article: PubMed Central - PubMed

Affiliation: Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang, 621900 (P.R. China).

ABSTRACT
Fused silica subwavelength structures (SWSs) with an average period of ~100 nm were fabricated using an efficient approach based on one-step self-masking reactive ion etching. The subwavelength structures exhibited excellent broadband antireflection properties from the ultraviolet to near-infrared wavelength range. These properties are attributable to the graded refractive index for the transition from air to the fused silica substrate that is produced by the ideal nanocone subwavelength structures. The transmittance in the 400-700 nm range increased from approximately 93% for the polished fused silica to greater than 99% for the subwavelength structure layer on fused silica. Achieving broadband antireflection in the visible and near-infrared wavelength range by appropriate matching of the SWS heights on the front and back sides of the fused silica is a novel strategy. The measured antireflection properties are consistent with the results of theoretical analysis using a finite-difference time-domain (FDTD) method. This method is also applicable to diffraction grating fabrication. Moreover, the surface of the subwavelength structures exhibits significant superhydrophilic properties.

No MeSH data available.