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Anisotropic TixSn1-xO2 nanostructures prepared by magnetron sputter deposition.

Chen S, Li Z, Zhang Z - Nanoscale Res Lett (2011)

Bottom Line: Regular arrays of TixSn1-xO2 nanoflakes were fabricated through glancing angle sputter deposition onto self-assembled close-packed arrays of 200-nm-diameter polystyrene spheres.The reflectance measurements showed that the melon seed-shaped nanoflakes exhibited optimal properties of antireflection in the entire visible and ultraviolet region.In addition, we determined their anisotropic reflectance in the direction parallel to the surface of nanoflakes and perpendicular to it, arising from the anisotropic morphology.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of New Ceramic and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China. zcli@tsinghua.edu.cn.

ABSTRACT
Regular arrays of TixSn1-xO2 nanoflakes were fabricated through glancing angle sputter deposition onto self-assembled close-packed arrays of 200-nm-diameter polystyrene spheres. The morphology of nanostructures could be controlled by simply adjusting the sputtering power of the Ti target. The reflectance measurements showed that the melon seed-shaped nanoflakes exhibited optimal properties of antireflection in the entire visible and ultraviolet region. In addition, we determined their anisotropic reflectance in the direction parallel to the surface of nanoflakes and perpendicular to it, arising from the anisotropic morphology.

No MeSH data available.


(a) Schematic illustration of the incident and reflected lights, with the reflectance in two directions marked as R// and R⊥, respectively; and (b) the R// and R⊥ of samples 1#-3# at the wavelength in the range of 200-750 nm.
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Figure 5: (a) Schematic illustration of the incident and reflected lights, with the reflectance in two directions marked as R// and R⊥, respectively; and (b) the R// and R⊥ of samples 1#-3# at the wavelength in the range of 200-750 nm.

Mentions: In view of the anisotropic morphology of the nanoflakes, the anisotropism of the optical property was studied. The reflectances of samples 1#, 2#, and 3# were measured using a spectrophotometer. Figure 5a shows the directions of the incident light. The reflectance in the direction parallel to the surface of nanoflakes is marked as R//, while the reflectance in the other direction is marked as R⊥. Figure 5b provides the R// and R⊥ of the samples 1#, 2#, and 3# in the spectral range of 200-750 nm. It indicates that the reflectance rises as the Ti content increases, and that the reflectance of sample 1# is almost wavelength independent, which agrees with the previously reported study on the optical properties of metal-dielectric composite media close to the percolation threshold [15-17]. In addition, it is notable that the reflectances of samples 1# and 2# are rather low, especially in the direction parallel to the surface of nanoflakes. This can be explained by the model of two-dimensional subwavelength antireflection nanogratings. The earlier report showed that the gradient-index layer may significantly influence the reducing reflection [18]. Hence, the gradient-duty cycle subwavelength nanogratings were designed to suppress the reflection, which functioned by providing a graded transition of the refractive index between air and the substrate [19-21]. Because of the gradient width and the thickening of the nanoflake with height, it can be approximately equivalent to a gradient-duty cycle subwavelength nanograting, which accounts for the effect of antireflection. Comparing the reflectance in two directions, it is evident that R// is apparently lower than R⊥ for all the samples. This feature can be attributed to the anisotropism of the morphology, which plays a crucial role in the anisotropism of the optical property. It demonstrates that the preparation method we proposed in this article can accomplish an adjustment to the morphology of nanostructures, and ultimately the tuning of the properties.


Anisotropic TixSn1-xO2 nanostructures prepared by magnetron sputter deposition.

Chen S, Li Z, Zhang Z - Nanoscale Res Lett (2011)

(a) Schematic illustration of the incident and reflected lights, with the reflectance in two directions marked as R// and R⊥, respectively; and (b) the R// and R⊥ of samples 1#-3# at the wavelength in the range of 200-750 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211414&req=5

Figure 5: (a) Schematic illustration of the incident and reflected lights, with the reflectance in two directions marked as R// and R⊥, respectively; and (b) the R// and R⊥ of samples 1#-3# at the wavelength in the range of 200-750 nm.
Mentions: In view of the anisotropic morphology of the nanoflakes, the anisotropism of the optical property was studied. The reflectances of samples 1#, 2#, and 3# were measured using a spectrophotometer. Figure 5a shows the directions of the incident light. The reflectance in the direction parallel to the surface of nanoflakes is marked as R//, while the reflectance in the other direction is marked as R⊥. Figure 5b provides the R// and R⊥ of the samples 1#, 2#, and 3# in the spectral range of 200-750 nm. It indicates that the reflectance rises as the Ti content increases, and that the reflectance of sample 1# is almost wavelength independent, which agrees with the previously reported study on the optical properties of metal-dielectric composite media close to the percolation threshold [15-17]. In addition, it is notable that the reflectances of samples 1# and 2# are rather low, especially in the direction parallel to the surface of nanoflakes. This can be explained by the model of two-dimensional subwavelength antireflection nanogratings. The earlier report showed that the gradient-index layer may significantly influence the reducing reflection [18]. Hence, the gradient-duty cycle subwavelength nanogratings were designed to suppress the reflection, which functioned by providing a graded transition of the refractive index between air and the substrate [19-21]. Because of the gradient width and the thickening of the nanoflake with height, it can be approximately equivalent to a gradient-duty cycle subwavelength nanograting, which accounts for the effect of antireflection. Comparing the reflectance in two directions, it is evident that R// is apparently lower than R⊥ for all the samples. This feature can be attributed to the anisotropism of the morphology, which plays a crucial role in the anisotropism of the optical property. It demonstrates that the preparation method we proposed in this article can accomplish an adjustment to the morphology of nanostructures, and ultimately the tuning of the properties.

Bottom Line: Regular arrays of TixSn1-xO2 nanoflakes were fabricated through glancing angle sputter deposition onto self-assembled close-packed arrays of 200-nm-diameter polystyrene spheres.The reflectance measurements showed that the melon seed-shaped nanoflakes exhibited optimal properties of antireflection in the entire visible and ultraviolet region.In addition, we determined their anisotropic reflectance in the direction parallel to the surface of nanoflakes and perpendicular to it, arising from the anisotropic morphology.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of New Ceramic and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China. zcli@tsinghua.edu.cn.

ABSTRACT
Regular arrays of TixSn1-xO2 nanoflakes were fabricated through glancing angle sputter deposition onto self-assembled close-packed arrays of 200-nm-diameter polystyrene spheres. The morphology of nanostructures could be controlled by simply adjusting the sputtering power of the Ti target. The reflectance measurements showed that the melon seed-shaped nanoflakes exhibited optimal properties of antireflection in the entire visible and ultraviolet region. In addition, we determined their anisotropic reflectance in the direction parallel to the surface of nanoflakes and perpendicular to it, arising from the anisotropic morphology.

No MeSH data available.