Abstract
Nature routinely produces nanostructured surfaces with useful properties1,2,3,4, such as the self-cleaning lotus leaf5, the colour of the butterfly wing6, the photoreceptor in brittlestar7 and the anti-reflection observed in the moth eye8. Scientists and engineers have been able to mimic some of these natural structures in the laboratory and in real-world applications9,10,11,12. Here, we report a simple aperiodic array of silicon nanotips on a 6-inch wafer with a sub-wavelength structure that can suppress the reflection of light at a range of wavelengths from the ultraviolet, through the visible part of the spectrum, to the terahertz region. Reflection is suppressed for a wide range of angles of incidence and for both s- and p-polarized light. The antireflection properties of the silicon result from changes in the refractive index caused by variations in the height of the silicon nanotips, and can be simulated with models that have been used to explain the low reflection from moth eyes8,13,14. The improved anti-reflection properties of the surfaces could have applications in renewable energy and electro-optical devices for the military.
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References
Lee, L. P. & Szema, R. Inspirations from biological optics for advanced photonic systems. Science 310, 1148–1150 (2005).
Vukusic, P. & Sambles, J. R. Photonic structures in biology. Nature 424, 852–855 (2003).
Parker, A. R. & Townley, H. E. Biomimetics of photonic nanostructures. Nature Nanotech. 2, 347–353 (2007).
Potyrailo, R. A. et al. Morpho butterfly wing scales demonstrate highly selective vapour response. Nature Photon. 1, 123–128 (2007).
Neinhuis, C. & Barthlott, W. Characterisation and distribution of water-repellent, self-cleaning plant surfaces. Ann. Bot. 79, 667–677 (1997).
Ghiradella, H. et al. Ultraviolet reflection of a male butterfly: Interference color caused by thin-layer elaboration of wing scales. Science 178, 1214–1217 (1972).
Aizenberg, J. et al. Calcitic microlenses as part of the photoreceptor system in brittlestars. Nature 412, 819–822 (2001).
Bernhard, C. G. Structural and functional adaptation in a visual system. Endeavour 26, 79–84 (1967).
Srinivasarao, M. Nano-optics in the biological world: beetles, butterflies, birds, and moths. Chem. Rev. 99, 1935–1961 (1999).
Feng, L. et al. Super-hydrophobic surfaces: From natural to artificial. Adv. Mater. 14, 1857–1860 (2002).
Gu, Z. Z. et al. Structural color and the lotus effect. Angew. Chem. Int. Edn 42, 894–897 (2003).
Groning, P. Nanotechnology: An approach to mimic natural architectures and concepts. Adv. Eng. Mater. 7, 279–291 (2005).
Clapham, P. B. & Hutley, M. C. Reduction of lens reflection by moth eye principle. Nature 244, 281–282 (1973).
Wilson, S. J. & Hutley, M. C. The optical-properties of moth eye antireflection surfaces. Optica Acta 29, 993–1009 (1982).
Southwell, W. H. Pyramid-array surface-relief structures producing antireflection index matching on optical-surfaces. J. Opt. Soc. Am. A 8, 549–553 (1991).
Grann, E. B. Moharam, M. G. & Pommet, D. A. Optimal-design for antireflective tapered two-dimensional subwavelength grating structures. J. Opt. Soc. Am. A 12, 333–339 (1995).
Xi, J. Q. et al. Optical thin-film materials with low refractive index for broadband elimination of Fresnel reflection. Nature Photon. 1, 176–179 (2007).
Lee, C. et al. A novel silicon nanotips antireflection surface for the micro sun sensor. Nano Lett. 5, 2438–2442 (2005).
Chattopadhyay, S., Chen, L. C. & Chen, K. H. Nanotips: Growth, model, and applications. Crit. Rev. Solid State Mater. Sci. 31, 15–53 (2006).
Striemer, C. C. & Fauchet, P. M. Dynamic etching of silicon for broadband antireflection applications. Appl. Phys. Lett. 81, 2980–2982 (2002).
Kanamori, Y., Sasaki, M. & Hane, K. Broadband antireflection gratings fabricated upon silicon substrates. Opt. Lett. 24, 1422–1424 (1999).
Kanamori, Y. et al. 100 nm period silicon antireflection structures fabricated using a porous alumina membrane mask. Appl. Phys. Lett. 78, 142–143 (2001).
Yu, Z. et al. Fabrication of large area subwavelength antireflection structures on Si using trilayer resist nanoimprint lithography and liftoff. J. Vac. Sci. Technol. B 21, 2874–2877 (2003).
Zaidi, S. H., Ruby, D. S. & Gee, J. M. Characterisation of random reactive ion etched-textured silicon solar cells. IEEE Trans. Electron Devices 48, 1200–1206 (2001).
Kanamori, Y., Ishimori, M. & Hane, K. High efficient light-emitting diodes with antireflection subwavelength gratings. IEEE Photon. Technol. Lett. 14, 1064–1066 (2002).
Glaser, T. et al. High temperature resistant antireflective moth-eye structures for infrared radiation sensors. Microsyst. Technol. 11, 86–90 (2005).
Hsu, C. H. et al. Generally applicable self-masked dry etching technique for nanotip array fabrication. Nano Lett. 4, 471–475 (2004).
Chen, K. H. et al. Method of forming a nanotip array in a substrate by forming masks on portions of the substrate and etching the unmasked portions. US patent 6,960,528 B2 (2005).
Hsu, C. H. et al. Morphology control of silicon nanotips fabricated by electron cyclotron resonance plasma etching. J. Vac. Sci. Technol. B 24, 308–311 (2006).
Macleod, H. A. in Thin Film Optical Filters 3rd edn (Taylor & Francis, London, 2001).
Minot. M. J. The angular reflectance of single-layer gradient refractive-index films. J. Opt. Soc. Am. 67, 1046–1050 (1977).
Dobrowolski, J. A. & Piotrowski, S. H. C. Refractive index as a variable in the numerical design of optical thin film systems. Appl. Opt. 21, 1502–1511 (1982).
Lalanne, P. & Morris, G. M. Antireflection behavior of silicon subwavelength periodic structures for visible light. Nanotechnology 8, 53–56 (1997).
Dobrowolski, J. A. et al. Toward perfect antireflection coatings. 3. Experimental results obtained with the use of Reststrahlen materials. Appl. Opt. 45, 1555–1562 (2006).
Poitras, D. et al. Toward perfect antireflection coatings. 2. Theory. Appl. Opt. 43, 1286–1295 (2004).
Tompkins, H. G. in A User's Guide to Ellipsometry (Academic Press, New York, 1999).
Gatesman, A. J. et al. An anti-reflection coating for silicon optics at terahertz frequencies. IEEE Microw. Guid. Wave Lett. 10, 264–266 (2000).
Brückner, C. et al. Broadband antireflective surface-relief structure for THz optics. Opt. Express 15, 779–789 (2007).
Acknowledgements
We acknowledge financial support from the Ministry of Education under the ATU plan and the National Science Council in Taiwan, the Air Force Office of Scientific Research, the Asian Office of Aerospace Research and Development and the US Army Research Office in the Far East.
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Y.F.H. conceived and performed the UV-VIS, IR and angle-dependent experiments; H.C.L. and C.H.H. synthesized the SiNTs; Y.H.C. and C.S.L. performed the far IR measurements; T.A.L. Y.K.H. and C.L.P. performed the THz measurements; Y.J.J. and C.Y.P. carried out the theoretical analyses; Y.F.H., S.C., K.H.C. and L.C.C. discussed and interpreted the result; and S.C., K.H.C. and L.C.C. co-wrote the paper.
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Huang, YF., Chattopadhyay, S., Jen, YJ. et al. Improved broadband and quasi-omnidirectional anti-reflection properties with biomimetic silicon nanostructures. Nature Nanotech 2, 770–774 (2007). https://doi.org/10.1038/nnano.2007.389
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DOI: https://doi.org/10.1038/nnano.2007.389
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