WorldWideScience

Sample records for antireflection coatings

  1. Sol-gel antireflective coating on plastics

    Science.gov (United States)

    Ashley, Carol S.; Reed, Scott T.

    1990-01-01

    An antireflection film made from a reliquified sol-gel hydrolyzation, condensation polymeric reaction product of a silicon, alkoxides and/or metal alkoxides, or mixtures thereof. The film is particularly useful for coating plastics.

  2. Plasmonic and silicon spherical nanoparticle antireflective coatings

    OpenAIRE

    Baryshnikova, K. V.; Petrov, M. I.; Babicheva, V. E.; Belov, P. A.

    2016-01-01

    Over the last decade, plasmonic antireflecting nanostructures have been extensively studied to be utilized in various optical and optoelectronic systems such as lenses, solar cells, photodetectors, and others. The growing interest to all-dielectric photonics as an alternative optical technology along with plasmonics motivates us to compare antireflective properties of plasmonic and all-dielectric nanoparticle coatings based on silver and crystalline silicon respectively. Our simulation result...

  3. Broadband antireflection coatings for multifunctional avionic displays

    Science.gov (United States)

    Kumari, Neelam; Kumar, Mukesh; Rao, P. K.; Karar, Vinod; Sharma, Amit Lochan

    2015-06-01

    Broadband Multilayer Antireflection (AR) coatings markedly improve the transmission efficiency of any optical component such as lens, prism, beam-splitter, beam combiner or a window. By reducing surface reflections over a wide wavelength range, broadband antireflection coatings improve transmission and enhance contrast which is desired in avionic displays. The broadband antireflection coating consisting of MgF2, ZrO2 and Al2O3 were designed to cover the whole visible spectrum and fabricated on optical grade glass substrate. The optical characterization of these coatings indicates reduction of the reflection to 2.28% as compared to 8.5 % at 545 nm (i.e. design wavelength of most avionic displays) for bare substrate making them useful in optical displays for avionic applications.

  4. Investigation of sol-gel antireflective coatings

    International Nuclear Information System (INIS)

    Very high power laser systems present material design challenges which often approach the inherent optical survival strength of components. Optical coatings in the UV region suffer from anomalously high absorption and scattering in the deposited layers. The losses caused by these effects are often unacceptable or, in the case of absorption, usually fatal to the absorbing coatings. Unfortunately, no metals exist that have high enough reflectivities in the UV to serve as uncoated mirrors as they normally do in the CO2 region of the infrared. Adequate multilayer dielectric coatings are therefore critically important for the development and utilization of UV lasers. The same could be said for relfection suppressing antireflective coatings in that wavelength range. Antireflective properties of gradientindex designs have been rediscovered and their potential for resolving UV laser design difficulties has been vigorously tested. These antireflective properties have been attained on glass or fused silica surfaces by chemical surface treatments

  5. ANTIREFLECTION MULTILAYER COATINGS WITH THIN METAL LAYERS

    Directory of Open Access Journals (Sweden)

    L. A. Gubanova

    2016-03-01

    Full Text Available The design of anti-reflective coatings for metal surfaces of Al, Ti, N,i Cr is proposed. The coatings have the form of alternating layers of dielectric/metal/dielectric with the number of cells up to15. The method of calculation of such coatings is proposed. We have calculated the coatings of the type [HfO2/Cr/HfO2]15, [ZrO2/Ti/Al2O3]15, [ZrO2/Cr/ZrO2]15. It is shown that the proposed interference coatings provide reduction of the residual reflectance of the metal several times (from 3.5 to 6.0 in a wide spectral range (300-1000 nm. The proposed coatings can be recommended as anti-reflective coatings for energy saving solar systems and batteries, and photovoltaic cells.

  6. Plasmonic and silicon spherical nanoparticle antireflective coatings

    Science.gov (United States)

    Baryshnikova, K. V.; Petrov, M. I.; Babicheva, V. E.; Belov, P. A.

    2016-03-01

    Over the last decade, plasmonic antireflecting nanostructures have been extensively studied to be utilized in various optical and optoelectronic systems such as lenses, solar cells, photodetectors, and others. The growing interest to all-dielectric photonics as an alternative optical technology along with plasmonics motivates us to compare antireflective properties of plasmonic and all-dielectric nanoparticle coatings based on silver and crystalline silicon respectively. Our simulation results for spherical nanoparticles array on top of amorphous silicon show that both silicon and silver coatings demonstrate strong antireflective properties in the visible spectral range. For the first time, we show that zero reflectance from the structure with silicon coatings originates from the destructive interference of electric- and magnetic-dipole responses of nanoparticle array with the wave reflected from the substrate, and we refer to this reflection suppression as substrate-mediated Kerker effect. We theoretically compare the silicon and silver coating effectiveness for the thin-film photovoltaic applications. Silver nanoparticles can be more efficient, enabling up to 30% increase of the overall absorbance in semiconductor layer. Nevertheless, silicon coatings allow up to 64% absorbance increase in the narrow band spectral range because of the substrate-mediated Kerker effect, and band position can be effectively tuned by varying the nanoparticles sizes.

  7. Plasmonic and silicon spherical nanoparticle antireflective coatings.

    Science.gov (United States)

    Baryshnikova, K V; Petrov, M I; Babicheva, V E; Belov, P A

    2016-01-01

    Over the last decade, plasmonic antireflecting nanostructures have been extensively studied to be utilized in various optical and optoelectronic systems such as lenses, solar cells, photodetectors, and others. The growing interest to all-dielectric photonics as an alternative optical technology along with plasmonics motivates us to compare antireflective properties of plasmonic and all-dielectric nanoparticle coatings based on silver and crystalline silicon respectively. Our simulation results for spherical nanoparticles array on top of amorphous silicon show that both silicon and silver coatings demonstrate strong antireflective properties in the visible spectral range. For the first time, we show that zero reflectance from the structure with silicon coatings originates from the destructive interference of electric- and magnetic-dipole responses of nanoparticle array with the wave reflected from the substrate, and we refer to this reflection suppression as substrate-mediated Kerker effect. We theoretically compare the silicon and silver coating effectiveness for the thin-film photovoltaic applications. Silver nanoparticles can be more efficient, enabling up to 30% increase of the overall absorbance in semiconductor layer. Nevertheless, silicon coatings allow up to 64% absorbance increase in the narrow band spectral range because of the substrate-mediated Kerker effect, and band position can be effectively tuned by varying the nanoparticles sizes. PMID:26926602

  8. Antireflective Coatings for Glass and Transparent Polymers.

    Science.gov (United States)

    Buskens, Pascal; Burghoorn, Marieke; Mourad, Maurice Christian Danho; Vroon, Zeger

    2016-07-12

    Antireflective coatings (ARCs) are applied to reduce surface reflections. We review coatings that reduce the reflection of the surface of the transparent substrates float glass, polyethylene terephthalate, poly(methyl methacrylate), and polycarbonate. Three main coating concepts exist to lower the reflection at the interface of a transparent substrate and air: multilayer interference coatings, graded index coatings, and quarter-wave coatings. We introduce and discuss these three concepts, and zoom in on porous quarter-wave coatings comprising colloidal particles. We extensively discuss the four routes for introducing porosity in quarter-wave coatings through the use of colloidal particles, which have the highest potential for application: (1) packing of dense nanospheres, (2) integration of voids through hollow nanospheres, (3) integration of voids through sacrificial particle templates, and (4) packing of nonspherical nanoparticles. Finally, we address the remaining challenges in the field of ARCs, and elaborate on potential strategies for future research in this area. PMID:27187719

  9. Optical enhancing durable anti-reflective coating

    Energy Technology Data Exchange (ETDEWEB)

    Maghsoodi, Sina; Varadarajan, Aravamuthan; Movassat, Meisam

    2016-07-05

    Disclosed herein are polysilsesquioxane based anti-reflective coating (ARC) compositions, methods of preparation, and methods of deposition on a substrate. In embodiments, the polysilsesquioxane of this disclosure is prepared in a two-step process of acid catalyzed hydrolysis of organoalkoxysilane followed by addition of tetralkoxysilane that generates silicone polymers with >40 mol % silanol based on Si-NMR. These high silanol siloxane polymers are stable and have a long shelf-life in the polar organic solvents at room temperature. Also disclosed are low refractive index ARC made from these compositions with and without additives such as porogens, templates, Si--OH condensation catalyst and/or nanofillers. Also disclosed are methods and apparatus for applying coatings to flat substrates including substrate pre-treatment processes, coating processes including flow coating and roll coating, and coating curing processes including skin-curing using hot-air knives. Also disclosed are coating compositions and formulations for highly tunable, durable, highly abrasion-resistant functionalized anti-reflective coatings.

  10. Self-Cleaning Antireflective Optical Coatings

    OpenAIRE

    Guldin, Stefan; Kohn, Peter; Stefik, Morgan; Song, Juho; Divitini, Giorgio; Ecarla, Fanny; Ducati, Caterina; Wiesner, Ulrich; Steiner, Ullrich

    2013-01-01

    Low-cost antireflection coatings (ARCs) on large optical surfaces are an ingredient-technology for high-performance solar cells. While nanoporous thin films that meet the zero-reflectance conditions on transparent substrates can be cheaply manufactured, their suitability for outdoor applications is limited by the lack of robustness and cleanability. Here, we present a simple method for the manufacture of robust self-cleaning ARCs. Our strategy relies on the self-assembly of a block-copolymer ...

  11. High gain durable anti-reflective coating

    Energy Technology Data Exchange (ETDEWEB)

    Maghsoodi, Sina; Brophy, Brenor L.; Colson, Thomas E.; Gonsalves, Peter R.; Abrams, Ze' ev R.

    2016-07-26

    Disclosed herein are polysilsesquioxane-based anti-reflective coating (ARC) compositions, methods of preparation, and methods of deposition on a substrate. In one embodiment, the polysilsesquioxane of this disclosure is prepared in a two-step process of acid catalyzed hydrolysis of organoalkoxysilane followed by addition of tetralkoxysilane that generates silicone polymers with >40 mol % silanol based on Si-NMR. These high silanol siloxane polymers are stable and have a long shelf-life in polar organic solvents at room temperature. Also disclosed are low refractive index ARC made from these compositions with and without additives such as porogens, templates, thermal radical initiator, photo radical initiators, crosslinkers, Si--OH condensation catalyst and nano-fillers. Also disclosed are methods and apparatus for applying coatings to flat substrates including substrate pre-treatment processes, coating processes and coating curing processes including skin-curing using hot-air knives. Also disclosed are coating compositions and formulations for highly tunable, durable, highly abrasion-resistant functionalized anti-reflective coatings.

  12. Scandium oxide antireflection coatings for superluminescent LEDs

    Science.gov (United States)

    Ladany, I.; Zanzucchi, P. J.; Andrews, J. T.; Kane, J.; Depiano, E.

    1986-01-01

    For an employment of laser diodes as superluminescent LEDs (SLDs) or amplifiers, the facets of the diodes must be coated with antireflection films. In the work reported, scandium oxide was evaporated from an e-beam source onto Supersil II fused silica substrates. The obtained samples were used for measurements of absorption and reflectivity. Results of index measurements on e-beam evaporated films are presented. It is shown that excellent coatings with reflectivities of 0.00025 can be obtained using these films. Attention is given to the refractive indices for scandium oxide films as a function of wavelength, the power output vs current for laser before coating and after coating with Sc2O3.

  13. Self-Cleaning Antireflective Optical Coatings

    KAUST Repository

    Guldin, Stefan

    2013-11-13

    Low-cost antireflection coatings (ARCs) on large optical surfaces are an ingredient-technology for high-performance solar cells. While nanoporous thin films that meet the zero-reflectance conditions on transparent substrates can be cheaply manufactured, their suitability for outdoor applications is limited by the lack of robustness and cleanability. Here, we present a simple method for the manufacture of robust self-cleaning ARCs. Our strategy relies on the self-assembly of a block-copolymer in combination with silica-based sol-gel chemistry and preformed TiO2 nanocrystals. The spontaneous dense packing of copolymer micelles followed by a condensation reaction results in an inverse opal-type silica morphology that is loaded with TiO2 photocatalytic hot-spots. The very low volume fraction of the inorganic network allows the optimization of the antireflecting properties of the porous ARC despite the high refractive index of the embedded photocatalytic TiO2 nanocrystals. The resulting ARCs combine high optical and self-cleaning performance and can be deposited onto flexible plastic substrates. © 2013 American Chemical Society.

  14. Advanced Antireflection Coatings for High-Performance Solar Energy Applications

    Science.gov (United States)

    Pan, Noren

    2015-01-01

    Phase II objectives: Develop and refine antireflection coatings incorporating lanthanum titanate as an intermediate refractive index material; Investigate wet/dry thermal oxidation of aluminum containing semiconductor compounds as a means of forming a more transparent window layer with equal or better optical properties than its unoxidized form; Develop a fabrication process that allows integration of the oxidized window layer and maintains the necessary electrical properties for contacting the solar cell; Conduct an experimental demonstration of the best candidates for improved antireflection coatings.

  15. High gain durable anti-reflective coating with oblate voids

    Energy Technology Data Exchange (ETDEWEB)

    Maghsoodi, Sina; Brophy, Brenor L.; Colson, Thomas E.; Gonsalves, Peter R.; Abrams, Ze' ev

    2016-06-28

    Disclosed herein are single layer transparent coatings with an anti-reflective property, a hydrophobic property, and that are highly abrasion resistant. The single layer transparent coatings contain a plurality of oblate voids. At least 1% of the oblate voids are open to a surface of the single layer transparent coatings.

  16. Optimization of broadband omnidirectional antireflection coatings for solar cells

    CERN Document Server

    Guo, Xia; Li, Chong; Zhou, Hongyi; Lv, Benshun; Feng, Yajie; Wang, Huaqiang; Liu, Wuming

    2015-01-01

    Broadband and omnidirectional antireflection coating is a generally effective way to improve solar cell efficiency, because the destructive interference between the reflected and input waves could maximize transmission light in the absorption layer. Several theoretical calculations have been developed to optimize the anti-reflective coating to maximize the average transmittance. However, the solar irradiances of the clear sky spectral direct beam on a receiver plane at different positions and times are variable greatly. Here we report a new theoretical calculation of anti-reflective coating with incident quantum efficiency {\\eta}in as evaluation function for practical application. The two-layer and three-layer anti-reflective coatings are optimized over {\\lambda} = [300, 1100] nm and {\\theta} = [0{\\deg}, 90{\\deg}] for cities of Quito, Beijing and Moscow. The {\\eta}in of two-layer anti-reflective coating increases by 0.26%, 1.37% and 4.24% for these 3 cities, respectively, compared with that other theoretical ...

  17. A novel trilayer antireflection coating using dip-coating technique

    Institute of Scientific and Technical Information of China (English)

    Jian Xu; Yi Yin; Haiming Ma; Hui Ye; Xu Liu

    2011-01-01

    We report a new structure for broadband antireflection coating by dip-coating technique,which has minimal cost and is compatible with large-scale manufacturing.The coatings are prepared by depositing SiO2 sol-gel film on a glass substrate,subsequently depositing SiO2 single-layer particle coating through electrostatic attraction,and depositing a final very thin Si02 sol-gel film to improve the mechanical strength of the whole coating structure.The refractive index of the structure changes gradually from the top to the substrate.The transmittance of a glass substrate has been experimentally found to be improved in the spectral range of 400-1400 nn and in the incidence angle range from 0° to at least 45°.The mechanical strength is immensely improved because of the additional thin Si02 sol-gel layer.The surface texture can be applied to the substrates of different materials and shapes as an add-on coating.

  18. Plasmonic and silicon spherical nanoparticle anti-reflective coatings

    CERN Document Server

    Baryshnikova, K V; Babicheva, V E; Belov, P A

    2015-01-01

    Over the last decade, plasmonic antireflecting nanostructures have been extensively studied to be utilized in various optical and optoelectronic systems such as lenses, solar cells, photodetectors, and others. The growing interest to all-dielectric photonics as an alternative optical technology along with plasmonics motivates us to compare antireflection properties of all-dielectric and plasmonic nanoparticle coatings based on silver and crystalline silicon. Our results of numerical simulations for periodic arrays of spherical nanoparticles on top of amorphous silicon show that both silicon and silver nanoparticle coatings demonstrate strong anti-reflective properties in the visible spectral range. In this work, we show for the first time that blooming effect, that is zero reflection from the structure, with silicon coatings originates from the interference of electric- and magnetic-dipole responses of nanoparticles with the wave reflected from the substrate, and we refer to it as substrate-mediated Kerker ef...

  19. Antireflection coatings for intraocular lenses of sapphire and fianite

    International Nuclear Information System (INIS)

    Broadband antireflection coatings for intraocular lenses of sapphire and fianite are calculated and implemented practically. Their residual reflectance in the liquid with a refracting index of 1.336 is below 0.2% from each face virtually over the entire visible region. 7 refs., 2 figs., 2 tabs

  20. Low-loss antireflection coating for the visible

    Science.gov (United States)

    Muscalu, G. L.

    1995-03-01

    It is shown the procedure of achieving a broadband antireflection coating for the visible. The coating structure is composed of 8 layers made of two materials: zirconium dioxide and magnesium fluoride. The experimental efficiency for getting a coating (for the admissibility criterion--specular reflection factor in the spectral (440 - 650) nm EQ 0.4% and average specular reflection factor in the same spectral EQ 0.3%) is 90%, when the coating is achieved under a vacuum system equipped with a photometer that operates at a single wavelength. The coating has the same performances when it is individualized on any type of glass with ne equals 1.48...1.90.

  1. Subwavelength metal grating metamaterial for polarization selective optical antireflection coating

    CERN Document Server

    Kim, Wonkyu; Hendrickson, Joshua

    2015-01-01

    A metamaterial structure consisting of a one-dimensional metal/air-gap subwavelength grating is investigated for optical antireflection coating on germanium substrate in the infrared regime. For incident light polarized perpendicularly to the grating lines, the metamaterial exhibits effective dielectric property and Fabry-Perot like plasmon-coupled optical resonance results in complete elimination of reflection and enhancement of transmission. It is found that the subwavelength grating metamaterial antireflection structure does not require a deep subwavelength grating period, which is advantageous for device fabrication. Maximal transmittance of 93.4% with complete elimination of reflection is seen in the mid-wave infrared range.

  2. Process and performance optimization of bottom antireflective coatings: II

    Science.gov (United States)

    Ding, Shuji; Sagan, John P.; Shan, Jianhui; Gonzalez, Eleazar; Dixit, Sunit S.; Liu, Ying; Khanna, Dinesh N.

    1999-06-01

    The newly developed AZ BARLi II coating material is a photoresist solvent-based bottom antireflective coating (BARC) for i-line lithographic application. The coating material has good compatibility with common edge bead removal solvents such as ethyl lactate, PGME, or PGMEA mixed with ethyl lactate or PGME. To evaluate the BARC material, its chemical compatibility with common EBR solvents has been tested by several analytical techniques including liquid particle counts and surface defect studies. Both top and bottom EBR dispense processes have been investigated and optimized. Improvements on edge roughness, visual cleanliness, and the BARC coating buildup at the edge will be discussed in this paper.

  3. Design of broadband omnidirectional antireflection coatings using ant colony algorithm.

    Science.gov (United States)

    Guo, X; Zhou, H Y; Guo, S; Luan, X X; Cui, W K; Ma, Y F; Shi, L

    2014-06-30

    Optimization method which is based on the ant colony algorithm (ACA) is described to optimize antireflection (AR) coating system with broadband omnidirectional characteristics for silicon solar cells incorporated with the solar spectrum (AM1.5 radiation). It's the first time to use ACA method for optimizing the AR coating system. In this paper, for the wavelength range from 400 nm to 1100 nm, the optimized three-layer AR coating system could provide an average reflectance of 2.98% for incident angles from Raveθ+ to 80° and 6.56% for incident angles from 0° to 90°. PMID:24978076

  4. Wide spectrum antireflective coating for laser fusion systems. Final report

    International Nuclear Information System (INIS)

    A method of depositing a laser damage resistant, wide-spectrum antireflective coating on fused silica has been developed. This work was sponsored under a subcontract with the University of California, with technical direction from the Lawrence Livermore National Laboratory. The coating is applied from a specific silanol polymer solution and converted to a porous SiO2 film. The pore size of the film is first reduced by a heat treatment to prevent uv scattering. Then gradation of the pore volume is achieved by a mild etching to a sufficient depth to prevent a smoother index transition from air to the substrate glass. The resulting antireflectivity covers the entire transmission range of silica and may be extended to a wavelength as short as 250 nm. Laser damage thresholds as high as 9 j/cm2 have been demonstrated on processed samples

  5. Estimation of reflection spectra for different type antireflection coatings to silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Aroutiounian, V.; Martirosyan, Kh. [Dept. Phys. Semicond. and Microelectronics, Yerevan State Univ., Yerevan (Armenia)

    2004-07-01

    In this letter, we simulate the cases of different types antireflection coatings made from porous silicon, dielectric mirrors, silicon oxynitride and silicon carbide to explore antireflection coating having advanced properties in solar cells. Using the optical matrix approach method, we calculate the reflectance of these structures. Comparing with the reflectance obtained for other antireflection coatings, we find a much lower reflectance in the UV-, visible- and IR-regions of the solar spectrum for these antireflection coatings, indicating the strong interest of the letters in solar cell applications. (orig.)

  6. Abrasion-resistant antireflective coating for polycarbonate

    Science.gov (United States)

    Wydeven, T. J.

    1978-01-01

    Following plasma-polymerization technique, treatment in oxygen glow discharge further enhances abrasion resistance and transmission. Improvement in abrasion resistance was shown by measuring percentage of haze resulting from abrasion. Coating samples were analyzed for abrasion using standard fresh rubber eraser. Other tests included spectra measurements and elemental analysis with spectrometers and spectrophotometers.

  7. Wide-band antireflection coatings; Breitbandige Antireflexbeschichtungen

    Energy Technology Data Exchange (ETDEWEB)

    Gombert, A.; Rommel, M. [Fraunhofer-Inst. fuer Solare Energiesysteme, Freiburg (Germany)

    1998-02-01

    In most cases, solar receivers - from solar collectors to buildings - have a transparent cover. In order to minimize the losses due to reflection, the aim is to find an AR coating which can be used for the broad bandwidth of the solar spectrum. Conventional solutions like multilayer systems with high and low refractive index layers are not suitable. The main problem is to produce layers with very low refractive indices. One solution which was investigated in the past is to synthesize layers with a low effective refractive index due to porosity; i.e. by mixing the bulk material with air on a subwavelength scale. Another possibility to achieve this mixture is given by subwave length surface-relief structures. Porous sol-gel coatings are suited for glass, subwavelength surface-relief structures can be replicated mainly in polymer materials by cheap embossing processes. (orig.) [Deutsch] Nahezu alle solaren Empfaenger sind transparent abgedeckt, z.B. durch Glascheiben. An diesen Abdeckungen wird ein Teil der einfallenden Solarstrahlung reflektiert. Diese Verluste koennen durch reflexionsmindernde Oberflaechen reduziert werden. Antireflexbeschichtungen, die z.B. fuer Brillenglaeser eingesetzt werden, eignen sich nicht fuer solare Entspiegelungen, da ihre spektrale Bandbreite nicht ausreicht. Das Hauptproblem liegt darin, dass Materialien mit sehr niedrigen Brechungsindices, wie sie fuer spektral breitbandige Antireflexbeschichtungen benoetigt werden, nicht verfuegbar sind. Der Ausweg besteht in poroesen Beschichtungen bzw. in einer Oberflaechenstrukturierung. Aufgrund des Luftanteils in der Mischung lassen sich sehr niedrige `effektive` Brechungsindices synthetisieren. Poroese Sol-Gel-Schichten eignen sich insbesondere zur Erhoehung der solaren Transmission von anorganischem Glas. Oberflaechenstrukturen sind aufgrund der Herstellbarkeit durch preisguenstige Praegeprozesse vielversprechend, finden aber derzeit ihre Anwendung ueberwiegend bei polymeren Materialien. (orig.)

  8. Ultraviolet antireflection coatings for use in silicon detector design

    Science.gov (United States)

    Hamden, Erika T.; Greer, Frank; Hoenk, Michael E.; Blacksberg, Jordana; Dickie, Matthew R.; Nikzad, Shouleh; Martin, D. Christopher; Schiminovich, David

    2011-07-01

    We report on the development of coatings for a charged-coupled device (CCD) detector optimized for use in a fixed dispersion UV spectrograph. Because of the rapidly changing index of refraction of Si, single layer broadband antireflection (AR) coatings are not suitable to increase quantum efficiency at all wavelengths of interest. Instead, we describe a creative solution that provides excellent performance over UV wavelengths. We describe progress in the development of a coated CCD detector with theoretical quantum efficiencies (QEs) of greater than 60% at wavelengths from 120 to 300nm. This high efficiency may be reached by coating a backside-illuminated, thinned, delta-doped CCD with a series of thin film AR coatings. The materials tested include MgF2 (optimized for highest performance from 120--150nm), SiO2 (150--180nm), Al2O3 (180--240nm), MgO (200--250nm), and HfO2 (240--300nm). A variety of deposition techniques were tested and a selection of coatings that minimized reflectance on a Si test wafer were applied to functional devices. We also discuss future uses and improvements, including graded and multilayer coatings.

  9. Ultraviolet antireflection coatings for use in silicon detector design

    International Nuclear Information System (INIS)

    We report on the development of coatings for a charged-coupled device (CCD) detector optimized for use in a fixed dispersion UV spectrograph. Because of the rapidly changing index of refraction of Si, single layer broadband antireflection (AR) coatings are not suitable to increase quantum efficiency at all wavelengths of interest. Instead, we describe a creative solution that provides excellent performance over UV wavelengths. We describe progress in the development of a coated CCD detector with theoretical quantum efficiencies (QEs) of greater than 60% at wavelengths from 120 to 300 nm. This high efficiency may be reached by coating a backside-illuminated, thinned, delta-doped CCD with a series of thin film AR coatings. The materials tested include MgF2 (optimized for highest performance from 120-150 nm), SiO2 (150-180 nm), Al2O3 (180-240 nm), MgO (200-250 nm), and HfO2 (240-300 nm). A variety of deposition techniques were tested and a selection of coatings that minimized reflectance on a Si test wafer were applied to functional devices. We also discuss future uses and improvements, including graded and multilayer coatings.

  10. Protective infrared antireflection coating based on sputtered germanium carbide

    Science.gov (United States)

    Gibson, Des; Waddell, Ewan; Placido, Frank

    2011-09-01

    This paper describes optical, durablility and environmental performance of a germanium carbide based durable antireflection coating. The coating has been demonstrated on germanium and zinc selenide infra-red material however is applicable to other materials such as zinc sulphide. The material is deposited using a novel reactive closed field magnetron sputtering technique, offering significant advantages over conventional evaporation processes for germanium carbide such as plasma enhanced chemical vapour deposition. The sputtering process is "cold", making it suitable for use on a wide range of substrates. Moreover, the drum format provide more efficient loading for high throughput production. The use of the closed field and unbalanced magnetrons creates a magnetic confinement that extends the electron mean free path leading to high ion current densities. The combination of high current densities with ion energies in the range ~30eV creates optimum thin film growth conditions. As a result the films are dense, spectrally stable, supersmooth and low stress. Films incorporate low hydrogen content resulting in minimal C-H absorption bands within critical infra-red passbands such as 3 to 5um and 8 to 12um. Tuning of germanium carbide (Ge(1-x)Cx) film refractive index from pure germanium (refractive index 4) to pure germanium carbide (refractive index 1.8) will be demonstrated. Use of film grading to achieve single and dual band anti-reflection performance will be shown. Environmental and durability levels are shown to be suitable for use in harsh external environments.

  11. Infrared 8- to 15-μm high-efficiency antireflection coating on germanium substrate

    Science.gov (United States)

    Ye, Ke-fei; Su, Zhaoxu; Liu, JiaHuan; Yang, Chongming

    1998-08-01

    To increase the strength of infrared high efficiency antireflection coatings is a problem difficult to be resolved. A mixture of BaF2 and CeF2 has been used as a low refractive index material to design and prepare infrared 8 - 11.5 (mu) high efficiency anti-reflection coating to acquire good strength of film layer. The processing conditions of the films deposition have also been introduced. The spectral transmittance measured, physical and chemical properties of the infrared anti-reflection coating are given.

  12. Antireflection coatings on plastics deposited by plasma polymerization process

    Indian Academy of Sciences (India)

    K M K Srivatsa; M Bera; A Basu; T K Bhattacharya

    2008-08-01

    Antireflection coatings (ARCs) are deposited on the surfaces of optical elements like spectacle lenses to increase light transmission and improve their performance. In the ophthalmic industry, plastic lenses are rapidly displacing glass lenses due to several advantageous features. However, the deposition of ARCs on plastic lenses is a challenging task, because the plastic surface needs treatment for adhesion improvement and surface hardening before depositing the ARC. This surface treatment is usually done in a multi-stage process—exposure to energetic radiations, followed by deposition of a carbonyl hard coating by spin or dip coating processes, UV curing, etc. However, this treatment can also be done by plasma processes. Moreover, the plasma polymerization process allows deposition of optical films at room temperature, essential for plastics. The energetic ions in plasma processes provide similar effects as in ion assisted physical deposition processes to produce hard coatings, without requiring sophisticated ion sources. The plasma polymerization process is more economical than ion-assisted physical vapour deposition processes as regards equipment and source materials and is more cost-effective, enabling the surface treatment and deposition of the ARC in the same deposition system in a single run by varying the system parameters at each step. Since published results of the plasma polymerization processes developed abroad are rather sketchy and the techniques are mostly veiled in commercial secrecy, innovative and indigenous plasma-based techniques have been developed in this work for depositing the complete ARCs on plastic substrates.

  13. Design Multilayer Antireflection Coatings for Terrestrial Solar Cells

    Directory of Open Access Journals (Sweden)

    Feng Zhan

    2014-01-01

    Full Text Available In order to analyze the influence of methods to design antireflection coatings (ARCs on reflectivity of broadband solar cells, we provide detailed analyses about the ARC coupled with a window layer and the refractive index dispersion effect of each layer. By multidimensional matrix data simulation, two methods were employed to measure the composite reflection of a SiO2/ZnS double-layer ARC within the spectral ranges of 300–870 nm (dual junction and 300–1850 nm (triple junction under AM1.5 solar radiation. A comparison study, between the results obtained from the commonly used weighted average reflectance method (WAR and that from the introduced effective average reflectance method (EAR, shows that the optimization of ARC by EAR method is convenient and feasible.

  14. Adhesion of Antireflective Coatings in Multijunction Photovoltaics: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Brock, Ryan; Dauskardt, Reinhold H.; Miller, David C.

    2016-06-16

    The development of a new composite dual cantilever beam (cDCB) thin-film adhesion testing method is reported, which allows the measurement of adhesion on the fragile thin substrates used in multijunction photovoltaics. We address the adhesion of several antireflective coating systems on multijunction cells. By varying interface chemistry and morphology, we demonstrate the ensuing effects on adhesion and help to develop an understanding of how high adhesion can be achieved, as adhesion values ranging from 0.5 J/m2 to 10 J/m2 were measured. Damp Heat (85 degrees C/85% RH) was used to invoke degradation of interfacial adhesion. We show that even with germanium substrates that fracture easily, quantitative measurements of adhesion can still be made at high test yield. The cDCB test is discussed as an important new methodology, which can be broadly applied to any system that makes use of thin, brittle, or otherwise fragile substrates.

  15. Optimization of multilayer antireflection coating for photovoltaic applications

    Science.gov (United States)

    Sikder, Urmita; Zaman, Mohammad Asif

    2016-05-01

    Multilayer antireflection coating (ARC) for photovoltaics is optimized using Differential Evolution (DE) algorithm. A general transfer-matrix based mathematical formulation is used for evaluating reflection spectra of the system. Exact and complete values of refractive indices are used in the analysis to provide higher accuracy of the results. The proposed optimization method takes into account the solar irradiance spectra, absorption characteristics of semiconductors and angle of incidence to maximize efficiency. This method is found to reduce the average reflectance for a wide range of angles of incidence. The proposed method is used to design ARC for silicon solar cell and a multi-junction AlGaAs/GaAs/Ge solar cell. Finally, comparative analysis of different ARC designs is provided in terms of corresponding solar cell characteristics.

  16. Development of Advanced Anti-Reflection Coatings for High Performance Solar Energy Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — MicroLink and its subcontractor Magnolia Solar will develop and demonstrate advanced anti-reflection coating (ARC) designs that will provide a better broadband and...

  17. Development of Advanced Anti-Reflection Coatings for High Performance Solar Energy Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — MicroLink Devices will increase the efficiency of multi-junction solar cells by designing and demonstrating advanced anti-reflection coatings (ARCs) that will...

  18. Nano-Enabled Low-Cost High-Performance UV Anti-Reflection Coatings Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this program, Agiltron and the groups of Professors Rubner and Cohen at MIT propose a novel nano-porous coating for next generation NASA UV anti-reflection (AR)...

  19. New nanoporous anti-reflective coating by water treatment of ALD deposited Al2O3

    OpenAIRE

    Isakov, Kirill

    2016-01-01

    In this work a process for fabricating nanoporous alumina anti-reflective coatings was developed. Anti-reflective coatings were designed for air-glass interface and soda-lime glass was used in the experiments. Alumina was deposited on glass by atomic layer deposition, and then transformed into nanoporous state by immersion in heated de-ionized water. The conditions for nanoporous alumina creation by de-ionized water treatment were investigated and the resulted structure was analysed with ...

  20. Broad Band Antireflection Coatings for Silicon and Germanium Substrates.

    Science.gov (United States)

    Bezuidenhout, Dirk Francois

    Infrared antireflection coatings for silicon and germanium substrates and some of the associated problems are addressed in this thesis. One of the first problems identified and investigated was that of the adhesion of ZnS films to germanium substrates. The cleaning of the Ge discs was evaluated by means of Auger spectroscopy. The main contaminant species found were carbon, oxygen and in the case of germanium substrates sulphur. No sulphur was found on silicon substrates. A wash in a series of organic solutions followed by a bake inside the vacuum chamber lead to much improved though still not acceptable adhesion of ZnS films to germanium substrates. The influence of a contact layer between the substrate and ZnS was investigated. Firstly, metal contact layers (Ni, Cr, Cu) were tried to improve the adhesion of the ZnS films. These samples (germanium-metal-zinc sulphide) were annealed in air in order to transfer the germanium -metal film to a germanide region and thus high optical transmission at long wave-lengths. Slight absorption still results even after the annealing of these samples. A dielectric material, Y_2O_3 , was therefore tested replacing the metal films. The system Ge-Y_2O_3 -ZnS in conjunction with an organic wash and vacuum bake lead to excellent adhesion of the ZnS layers to the germanium substrates. The next problem area addressed was that of a low refractive index material replacement for ThF _4. Four materials were investigated, i.e. ZnS, PbF_2, Y_2O _3 and YF_3. The refractive indices found for these compounds in thin film form at a wavelength of 10 μm is 2,18 for ZnS, 1,7 for PbF_2, 1,42 for Y_2O_3 and 1,3 for YF_3. From these results YF_3 was chosen as low refractive index material in the coating designs. Multi-layer coatings incorporating ZnS, Ge and YF_3 films were designed and evaporated. Measured reflectance values below 0,2% were obtained from 9 μm to 11 mum. These systems were stable and robust. Finally, a silicon ball lens was

  1. Comparative Study Between Various Antireflective Coatings For Solar Cells Applications

    International Nuclear Information System (INIS)

    The incessant progress in thin layers technology, especially inhomogeneous materials with variable index allows the fabrication of antireflective coating (ARC) less sensitive to the thickness and the incidence angle. Accordingly, our work is devoted to study the optical behaviour of graded refractive index ARC made from: silicon oxynitrides (SiOxNy), mixture of silicon and titanium oxides (SiO2-TiO2) and porous silicon (P-Si), for solar applications. The refractive index of the studied ARC varies versus thickness according to Fermi profile variation law. The physical parameters of such coating are its: thickness, form factor, profile inflection point and silica or air (porosity) volume fraction variation at the two interfaces (air/ARC and ARC/substrate). The optimisation of the studied films performance shows that best results are obtained with P-Si ARC, which reduce weighted reflectance till to 1.86% (between 300-1100 nm) leading to an improvement in photogenerated current of 51%.

  2. Thin film type 248-nm bottom antireflective coatings

    Science.gov (United States)

    Enomoto, Tomoyuki; Nakayama, Keisuke; Mizusawa, Kenichi; Nakajima, Yasuyuki; Yoon, Sangwoong; Kim, Yong-Hoon; Kim, Young-Ho; Chung, Hoesik; Chon, Sang Mun

    2003-06-01

    A frequent problem encountered by photoresists during the manufacturing of semiconductor device is that activating radiation is reflected back into the photoresist by the substrate. So, it is necessary that the light reflection is reduced from the substrate. One approach to reduce the light reflection is the use of bottom anti-reflective coating (BARC) applied to the substrate beneath the photoresist layer. The BARC technology has been utilized for a few years to minimize the reflectivity. As the chip size is reduced to sub 0.13-micron, the photoresist thickness has to decrease with the aspect ratio being less than 3.0. Therefore, new Organic BARC is strongly required which has the minimum reflectivity with thinner BARC thickness and higher etch selectivity towards resist. SAMSUNG Electronics has developed the advanced Organic BARC with Nissan Chemical Industries, Ltd. and Brewer Science, Inc. for achieving the above purpose. As a result, the suitable high performance SNAC2002 series KrF Organic BARCs were developed. Using CF4 gas as etchant, the plasma etch rate of SNAC2002 series is about 1.4 times higher than that of conventional KrF resists and 1.25 times higher than the existing product. The SNAC2002 series can minimize the substrate reflectivity at below 40nm BARC thickness, shows excellent litho performance and coating properties.

  3. Optimization of antireflection coating design for multijunction solar cells and concentrator systems

    Science.gov (United States)

    Valdivia, Christopher E.; Desfonds, Eric; Masson, Denis; Fafard, Simon; Carlson, Andrew; Cook, John; Hall, Trevor J.; Hinzer, Karin

    2008-06-01

    Photovoltaic solar cells are a route towards local, environmentally benign, sustainable and affordable energy solutions. Antireflection coatings are necessary to input a high percentage of available light for photovoltaic conversion, and therefore have been widely exploited for silicon solar cells. Multi-junction III-V semiconductor solar cells have achieved the highest efficiencies of any photovoltaic technology, yielding up to 40% in the laboratory and 37% in commercial devices under varying levels of concentrated light. These devices benefit from a wide absorption spectrum (300- 1800 nm), but this also introduces significant challenges for antireflection coating design. Each sub-cell junction is electrically connected in series, limiting the overall device photocurrent by the lowest current-producing junction. Therefore, antireflection coating optimization must maximize the current from the limiting sub-cells at the expense of the others. Solar concentration, necessary for economical terrestrial deployment of multi-junction solar cells, introduces an angular-dependent irradiance spectrum. Antireflection coatings are optimized for both direct normal incidence in air and angular incidence in an Opel Mk-I concentrator, resulting in as little as 1-2% loss in photocurrent as compared to an ideal zero-reflectance solar cell, showing a similar performance to antireflection coatings on silicon solar cells. A transparent conductive oxide layer has also been considered to replace the metallic-grid front electrode and for inclusion as part of a multi-layer antireflection coating. Optimization of the solar cell, antireflection coating, and concentrator system should be considered simultaneously to enable overall optimal device performance.

  4. Quantitative Adhesion Characterization of Antireflective Coatings in Multijunction Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Brock, Ryan; Rewari, Raunaq; Novoa, Fernando D.; Hebert, Peter; Ermer, James; Miller, David C.; Dauskardt, Reinhold H.

    2016-08-01

    We discuss the development of a new composite dual cantilever beam (cDCB) thin-film adhesion testing method, which enables the quantitative measurement of adhesion on the thin and fragile substrates used in multijunction photovoltaics. In particular, we address the adhesion of several 2- and 3-layer antireflective coating systems on multijunction cells. By varying interface chemistry and morphology through processing, we demonstrate the marked effects on adhesion and help to develop an understanding of how high adhesion can be achieved, as adhesion values ranging from 0.5 J/m2 to 10 J/m2 were measured. Damp heat (85 degrees C/85% RH) was used to invoke degradation of interfacial adhesion. We demonstrate that even with germanium substrates that fracture relatively easily, quantitative measurements of adhesion can be made at high test yield. The cDCB test is discussed as an important new methodology, which can be broadly applied to any system that makes use of thin, brittle, or otherwise fragile substrates.

  5. Wideband antireflection coatings on germanium and filters for second optical window

    Science.gov (United States)

    Ciosek, Jerzy; Firak, Jozef; Stanislawek, Urszula; Kwasny, Miroslaw; Kopczynski, Krzysztof

    2003-10-01

    The investigation results of wideband (8-12 μm) antireflection coatings on germanium substrate and spectral characteristics of interference wideband filter for spectral range of 8-12 μm are presented. For design of filters and antireflection coatings the following layer materials were used: Ge, ZnS and Mira, and substrate materials such as: Ge for antireflection coatings and ZnSe for interference filters. Wideband filter for the range of 8-12 μm requires application of additional two filters cutting off radiation from the range of 1-7 μm. The cutting off filters are interference filters for which construction germanium, Mira, and ZnS were used. The constructions of basic and cutting off filters were designed considering technical possibilities of vacuum device BAK 550 of the Balzers firm.

  6. Calculation of reflectance of porous silicon double-layer antireflection coating for silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Martirosyan, Kh.S.; Hovhannisyan, A.S.; Aroutiounian, V.M. [Department of Physics of Semiconductors and Microelectronics, Yerevan State University, 375025 Yerevan (Armenia)

    2007-07-01

    Calculations of the reflectance spectrum of the double-layer porous silicon antireflection coating for silicon solar cells were carried out using optical matrix approach method. Comparison of obtained reflectance spectrum of double-layer porous silicon with the spectra obtained experimentally without optimization of parameters of layers and for the SiO{sub 2}/TiO{sub 2} antireflection coating was shown lower reflectance value for this new construction proposed by us. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Anti-reflective and anti-soiling coatings for self-cleaning properties

    Energy Technology Data Exchange (ETDEWEB)

    Brophy, Brenor L.; Nair, Vinod; Dave, Bakul Champaklal

    2016-05-31

    The disclosure discloses abrasion resistant, persistently hydrophobic and oleophobic, anti-reflective and anti-soiling coatings for glass. The coatings described herein have wide application, including for example the front cover glass of solar modules. Methods of applying the coatings using various apparatus are disclosed. Methods for using the coatings in solar energy generation plants to achieve greater energy yield and reduced operations costs are disclosed. Coating materials are formed by combinations of hydrolyzed silane-base precursors through sol-gel processes. Several methods of synthesis and formulation of coating materials are disclosed.

  8. Design of multi-layer anti-reflection coating for terrestrial solar panel glass

    Indian Academy of Sciences (India)

    B GEETHA PRIYADARSHINI; A K SHARMA

    2016-06-01

    To date, there is no ideal anti-reflection (AR) coating available on solar glass which can effectively transmit the incident light within the visible wavelength range. However, there is a need to develop multifunctional coatingwith superior anti-reflection properties and self-cleaning ability meant to be used for solar glass panels. In spite of self-cleaning ability of materials like TiO2 and ZnO, these coatings on glass substrate have tendency to reduce lighttransmission due to their high refractive indices than glass. Thus, to infuse the anti-reflective property, a low refractive index, SiO$_2$ layer needs to be used in conjunction with TiO$_2$ and ZnO layers. In such case, the optimization ofindividual layer thickness is crucial to achieve maximum transmittance of the visible light. In the present study, we propose an omni-directional anti-reflection coating design for the visible spectral wavelength range of 400–700 nm,where the maximum intensity of light is converted into electrical energy. Herein, we employ the quarter wavelength criteria using SiO$_2$, TiO$_2$ and ZnO to design the coating composed of single, double and triple layers. The thicknessof individual layers was optimized for maximum light transmittance using essential Mcleod simulation software to produce destructive interference between reflected waves and constructive interference between transmitted waves.

  9. An in-situ monitoring technique for optimizing antireflection coatings using a monolithic integrated photodetector

    DEFF Research Database (Denmark)

    Saini, Vikram; Yvind, Kresten; Larsson, David

    2006-01-01

    A very low reflectivity of the order of 10-4 is demonstrated for dual-layer anti-reflection coatings on normal facet semiconductor lasers, by integrated in situ monitoring. The method has been tested on three and eight quantum-well InGaAsP ridge lasers that consist of a gain section and an...

  10. Characterization of single layer anti-reflective coatings for bolometer-based rare event searches

    CERN Document Server

    Hansen, E V

    2016-01-01

    A photon signal added to the existing phonon signal can powerfully reduce backgrounds for bolometer-based rare event searches. Anti-reflective coatings can significantly increase the performance of the secondary light sensing bolometer in these experiments. Coatings of SiO2, HfO2, and TiO2 on Ge and Si were fabricated and characterized at room temperature and all angles of incidence.

  11. Modified porous silica antireflective coatings with laser damage resistance for Ti:sapphire

    Science.gov (United States)

    Jia, Qiaoying; Li, Haiyuan; Liu, Ruijun; Tang, Yongxing; Jiang, Zhonghong

    2005-04-01

    Porous SiO2 antireflective (AR) coatings are prepared from the colloidal silica solution modified with methyltriethoxysilane (MTES) based on the sol-gel route. The viscosity of modified silica suspensions changes but their stability keeps when MTES is introduced. The refractive indices of modified coatings vary little after bake treatment from 100 to 150 Celsius. The modified silica coatings on Ti:sapphire crystal, owning good homogeneity, display prominent antireflective effect within the laser output waveband (750-850 nm) of Ti:sapphire lasers, with average transmission above 98.6%, and own laser induced damage thresholds (LIDTs) of more than 2.2 J/cm2 at 800 nm with the pulse duration of 300 ps.

  12. Scale-up of Nano-Engineered Anti-Reflection Coating Process for Large Plastic Optics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In a recently completed NASA SBIR program, Agiltron and the Massachusetts Institute of Technology developed a novel nanoporous UV anti-reflection coating technology...

  13. Technological peculiarities of deposition anti-reflective layers in low-e coatings

    Science.gov (United States)

    Yurjev, Y.; Sidelev, D.

    2013-12-01

    This article reports on the investigation of technological features magnetron sputtering for deposition anti-reflection layers in low-emission (low-e) coatings. The three-layer TiO2-Cu-TiO2 films were deposited by dual and planar magnetron sputtering systems (MS) on glass substrate. Studies of the current-voltage characteristics (CVC) and the hysteresis effect show that deposition of anti-reflection layers is possible in the transition mode with higher rates. For planar magnetron, the stability of electrical discharge parameters is achieved at 60 % O2 content in mixture. The calculations optical band gap Eg show that anti-reflective films have a rutile or anatase phases that depending on the content O2 in gas mixture. The optimum deposition conditions of TiO2 films were determined for all modifications of magnetrons. Anti-reflective layers, which are deposited by balanced dual MS, improve the transparency of low-e coatings (integral TVIS increase in 15%).

  14. Technological peculiarities of deposition anti-reflective layers in low-e coatings

    International Nuclear Information System (INIS)

    This article reports on the investigation of technological features magnetron sputtering for deposition anti-reflection layers in low-emission (low-e) coatings. The three-layer TiO2-Cu-TiO2 films were deposited by dual and planar magnetron sputtering systems (MS) on glass substrate. Studies of the current-voltage characteristics (CVC) and the hysteresis effect show that deposition of anti-reflection layers is possible in the transition mode with higher rates. For planar magnetron, the stability of electrical discharge parameters is achieved at 60 % O2 content in mixture. The calculations optical band gap Eg show that anti-reflective films have a rutile or anatase phases that depending on the content O2 in gas mixture. The optimum deposition conditions of TiO2 films were determined for all modifications of magnetrons. Anti-reflective layers, which are deposited by balanced dual MS, improve the transparency of low-e coatings (integral TVIS increase in 15%)

  15. Low reflectance of diamond-like carbon/porous silicon double layer antireflection coating for silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Aroutiounian, V M [Department of Semiconductor Physics and Microelectronics, Yerevan State University, 1 Alex Manoogian Street, Yerevan 375025 (Armenia); Martirosyan, Kh [Department of Semiconductor Physics and Microelectronics, Yerevan State University, 1 Alex Manoogian Street, Yerevan 375025 (Armenia); Soukiassian, P [Commissariat a l' Energie Atomique, Laboratoire SIMA associe a l' Universite Paris-Sud/Orsay, DSM-DRECAM-SPCSI, Saclay, Batiment 462, 91191 Gif sur Yvette Cedex (France)

    2004-10-07

    Reflectance calculations for diamond-like carbon (DLC) antireflection thin-film coatings on porous silicon (PS) have been carried out using the optical matrix approach method. Comparison with the reflectance spectrum obtained for other antireflection coatings shows a much lower reflectance with a larger energy range including the ultraviolet, visible and infrared regions of the solar spectrum for the DLC/PS double layer. This finding is relevant in solar cell applications. (rapid communication)

  16. Fabrication of superhydrophilic and antireflective silica coatings on poly(methyl methacrylate) substrates

    Energy Technology Data Exchange (ETDEWEB)

    Geng, Zhi [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences (CAS) (China); Graduate University of Chinese Academy of Sciences (China); He, Junhui, E-mail: jhhe@mail.ipc.ac.cn [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences (CAS) (China); Xu, Ligang [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences (CAS) (China); Graduate University of Chinese Academy of Sciences (China)

    2012-06-15

    Graphical abstract: Self-cleaning and antireflection properties were successfully achieved by assembling (PDDA/S-20){sub n} coatings on PMMA substrates followed by oxygen plasma treatment. Highlights: ► Porous silica coatings were created by layer-by-layer assembly on PMMA substrates. ► Silica coatings were treated by oxygen plasma. ► Porous silica coatings were highly antireflective and superhydrophilic on PMMA substrates. -- Abstract: Silica nanoparticles of ca. 20 nm in size were synthesized, from which hierarchically porous silica coatings were fabricated on poly(methyl methacrylate) (PMMA) substrates via layer-by-layer (LbL) assembly followed by oxygen plasma treatment. These porous silica coatings were highly transparent and superhydrophilic. The maximum transmittance reached as high as 99%, whereas that of the PMMA substrate is only 92%. After oxygen plasma treatment, the time for a water droplet to spread to a contact angle of lower than 5° decreased to as short as 0.5 s. Scanning and transmission electron microscopy were used to observe the morphology and structure of nanoparticles and coating surfaces. Transmission and reflection spectra were recorded on UV–vis spectrophotometer. Surface wettability was studied by a contact angle/interface system. The influence of mesopores on the transmittance and wetting properties of coatings was discussed on the basis of experimental observations.

  17. Fabrication of superhydrophilic and antireflective silica coatings on poly(methyl methacrylate) substrates

    International Nuclear Information System (INIS)

    Graphical abstract: Self-cleaning and antireflection properties were successfully achieved by assembling (PDDA/S-20)n coatings on PMMA substrates followed by oxygen plasma treatment. Highlights: ► Porous silica coatings were created by layer-by-layer assembly on PMMA substrates. ► Silica coatings were treated by oxygen plasma. ► Porous silica coatings were highly antireflective and superhydrophilic on PMMA substrates. -- Abstract: Silica nanoparticles of ca. 20 nm in size were synthesized, from which hierarchically porous silica coatings were fabricated on poly(methyl methacrylate) (PMMA) substrates via layer-by-layer (LbL) assembly followed by oxygen plasma treatment. These porous silica coatings were highly transparent and superhydrophilic. The maximum transmittance reached as high as 99%, whereas that of the PMMA substrate is only 92%. After oxygen plasma treatment, the time for a water droplet to spread to a contact angle of lower than 5° decreased to as short as 0.5 s. Scanning and transmission electron microscopy were used to observe the morphology and structure of nanoparticles and coating surfaces. Transmission and reflection spectra were recorded on UV–vis spectrophotometer. Surface wettability was studied by a contact angle/interface system. The influence of mesopores on the transmittance and wetting properties of coatings was discussed on the basis of experimental observations.

  18. Interference multilayer antireflection coatings for two wavelengths in the near infrared

    Science.gov (United States)

    Pencheva, Tamara G.; Nenkov, Milen; Michev, Javor

    2001-04-01

    The investigation deals with analysis of antireflection coatings of two transparent materials with high (H) and low (L) refractive index for two wavelengths 1.30 micrometer and 1.55 micrometer in the near IR on glass/silica substrates. The results are obtained by numerical optimization approach which algorithms are realized using programming language DELPHI. The initial structures of LHL three-layer and LHLH four-layer coating (optimized for both wavelengths) are modifications of double-layer antireflection coating for one wavelength 1.4 micrometer. It is shown that the highest transmittance near 1.30 and 1.55 micrometer (practically equal to 100%) shows LHLH four-layer coating structure. The total physical and optical thickness of optimized LHLH four-layer coating is smaller than corresponding value for optimized LHL three-layer coating. Four-layer LHLH coating is more stable with respect to small n and d variations and corresponding transmittance changes are less than in case of LHL three-layer coating.

  19. Broadband antireflection and field emission properties of TiN-coated Si-nanopillars.

    Science.gov (United States)

    Chang, Yuan-Ming; Ravipati, Srikanth; Kao, Pin-Hsu; Shieh, Jiann; Ko, Fu-Hsiang; Juang, Jenh-Yih

    2014-08-21

    Broadband antireflection and field emission characteristics of silicon nanopillars (Si-NPs) fabricated by self-masking dry etching in hydrogen-containing plasma were systematically investigated. In particular, the effects of ultrathin (5-20 nm) titanium nitride (TiN) films deposited on Si-NPs by atomic layer deposition (ALD) on the optoelectronic properties were explored. The results showed that by coating the Si-NPs with a thin layer of TiN the antireflection capability of pristine Si-NPs can be significantly improved, especially in the wavelength range of 1000-1500 nm. The enhanced field emission characteristics of these TiN/Si-NP heterostructures suggest that, in addition to the reflectance suppression in the long wavelength range arising from the strong wavelength-dependent refractive index of TiN, the TiN-coating may have also significantly modified the effective work function at the TiN/Si interface as well. PMID:25029029

  20. Plasma polymerized coating for polycarbonate - Single layer, abrasion resistant, and antireflection

    Science.gov (United States)

    Wydeven, T.

    1977-01-01

    Plasma polymerized vinyltrimethoxy silane films were deposited on transparent polycarbonate substrates. The adherent, clear films protected the substrates from abrasion and also served as antireflection coatings. Posttreatment of the vinyltrimethoxy silane films in an oxygen glow discharge further improved the abrasion resistance. ESCA (electron spectroscopy for chemical analysis) and IR transmission spectra of some films were recorded, and an elemental analysis of the films was obtained.

  1. Low-Doping Effect on Nano structured ZnO: Al as Anti-Reflecting Coating

    International Nuclear Information System (INIS)

    The effects of substituting low concentration Al at Zn-site as an anti-reflecting coating (ARC) for Zn1-xAlxO compound on structural, morphological and optical properties have been studied. Zn1-xAlxO sample with x = 0.00, 0.05, 0.10 and 0.15 were synthesized via a sol gel method. The films obtained from the sol gel have been annealed at 400 degree Celsius for 2 hours. X-ray diffraction Method (XIR) and Scanning Electron Microscope (SEM) have been used for structural characterization and morphology of the film. XRD spectra show all samples exhibit hexagonal structure. The particle size decreases with increasing Al concentration. These films exhibit a dense and compact film structure that could be effective for light trapping in thin film solar cells. The optical property has been characterised using UV-Visible-NIR and photoluminescence spectrometer. The band gaps increase as the concentration of Al increases. The increase of the band gap is an important requirement for good anti-reflecting coating element. Therefore these films can be applied as anti-reflecting coating thin film for solar cells. (author)

  2. Epoxy-based broadband anti-reflection coating for millimeter-wave optics

    CERN Document Server

    Rosen, Darin; Keating, Brian; Krantz, William; Lee, Adrian T; Quealy, Erin; Richards, Paul L; Siritanasak, Praween; Walker, William

    2013-01-01

    We have developed epoxy-based, broadband anti-reflection coatings for millimeter-wave astrophysics experiments with cryogenic optics. By using multiple-layer coatings where each layer steps in dielectric constant, we achieved low reflection over a wide bandwidth. We suppressed the reflection from an alumina disk to 10% over fractional bandwidths of 92% and 104% using two-layer and three-layer coatings, respectively. The dielectric constants of epoxies were tuned between 2.06 and 7.44 by mixing three types of epoxy and doping with strontium titanate powder required for the high dielectric mixtures. At 140 Kelvin, the band-integrated absorption loss in the coatings was suppressed to less than 1% for the two-layer coating, and below 10% for the three-layer coating.

  3. Ion-assisted deposition of yttrium fluoride as a substitute for thorium fluoride: application to infrared antireflection coating on germanium

    Science.gov (United States)

    Robic, Jean-Yves; Rolland, Bernard; Deutsch, Jean-Claude; Gallais, Patrick

    1994-11-01

    Yttrium fluoride has been proposed as a substitute for thorium fluoride in anti-reflection coatings for the infrared range. We have studied the ion assisted deposition (IAD) of YF3 in order to obtain dense and low absorbency layers in the 8 to 12 mm spectral window. Refractive index and extinction coefficient of this fluoride were determined from spectrophotometry measurements. We have then associated the YF3 with ZnS and Ge layers so as to obtain four layer anti-reflection coatings on germanium. The stress induced by each layer in the coating was measured and the sum was shown to be equal to the stress of the total coating. Eventually, an industrial, high efficiency, both side anti-reflection coating on germanium was developed using IAD YF3 film.

  4. Broad-bandwidth Metamaterial Antireflection Coatings for Sub-Millimeter Astronomy and CMB Foreground Removal

    Science.gov (United States)

    McMahon, Jeff

    Sub-millimeter observations are crucial for answering questions about star and galaxy formation; understanding galactic dust foregrounds; and for removing these foregrounds to detect the faint signature of inflationary gravitational waves in the polarization of the Cosmic Microwave Background (CMB). Achieving these goals requires improved, broad-band antireflection coated lenses and half-wave plates (HWPs). These optical elements will significantly boost the sensitivity and capability of future sub-millimeter and CMB missions. We propose to develop wide-bandwidth metamaterial antireflection coatings for silicon lenses and sapphire HWPs with 3:1 ratio bandwidth that are scalable across the sub-millimeter band from 300 GHz to 3 THz. This is an extension of our successful work on saw cut metamaterial AR coatings for silicon optics at millimeter wave lengths. These, and the proposed coatings consist of arrays of sub-wavelength scale features cut into optical surfaces that behave like simple dielectrics. We have demonstrated saw cut 3:1 bandwidth coatings on silicon lenses, but these coatings are limited to the millimeter wave band by the limitations of dicing saw machining. The crucial advance needed to extend these broad band coatings throughout the sub-millimeter band is the development of laser cut graded index metamaterial coatings. The proposed work includes developing the capability to fabricate these coatings, optimizing the design of these metamaterials, fabricating and testing prototype lenses and HWPs, and working with the PIPER collaboration to achieve a sub-orbital demonstration of this technology. The proposed work will develop potentially revolutionary new high performance coatings for the sub-millimeter bands, and cary this technology to TRL 7 paving the way for its use in space. We anticipate that there will be a wide range of applications for these coatings on future NASA balloons and satellites.

  5. Plasma-polymerized coating for polycarbonate: Single-layer, abrasion resistant, and antireflection

    Science.gov (United States)

    Wydeven, Theodore

    1991-01-01

    Plasma-polymerized vinyl trimethoxy silane films were deposited on transparent polycarbonate substrates. The adherent, clear films protected the substrates from abrasion and also served as antireflection coatings. Post-treatment of the vinyl trimethoxy silane films in an oxygen glow discharge further improved their abrasion resistance. The coatings were characterized by elemental analysis of the bulk, ESCA analysis of the surface, transmission, thickness, abrasion resistance, haze, and adhesion. This patented process is currently used by the world's largest manufacturers of non-prescription sunglasses to protect the plastic glasses from scratching and thereby to increase their useful lifetime.

  6. High-performance antireflective coatings with a porous nanoparticle layer for visible wavelengths.

    Science.gov (United States)

    Murata, Tsuyoshi; Ishizawa, Hitoshi; Tanaka, Akira

    2011-03-20

    Ghosts and flares are well-known problems that are caused by reflections from lens surfaces when we take photographs. It is more difficult to prevent such stray light in a digital camera than in a film camera because of high reflectance from the low-pass filter and diffraction from the image sensor. To prevent such stray light, we introduce an ultralow refractive index layer into the antireflective (AR) coatings. We used the solgel method to form porous fluoride layers with ultralow refractive indices, and we succeeded in developing a unique process to form AR coatings with superior performance. PMID:21460972

  7. UV anti-reflection coatings for use in silicon detector design

    CERN Document Server

    Hamden, Erika T; Hoenk, Michael E; Blacksberg, Jordana; Dickie, Matthew R; Nikzad, Shouleh; Martin, Christopher D; Schiminovich, David

    2011-01-01

    We report on the development of coatings for a CCD detector optimized for use in a fixed dispersion UV spectrograph. Due to the rapidly changing index of refraction of Si, single layer broadband anti-reflection coatings are not suitable to increase quantum efficiency at all wavelengths of interest. Instead, we describe a creative solution that provides excellent performance over UV wavelengths. We describe progress in the development of a CCD detector with theoretical quantum efficiencies (QE) of greater than 60% at wavelengths from 120 to 300nm. This high efficiency may be reached by coating a backside illuminated, thinned, delta-doped CCD with a series of thin film anti-reflection coatings. The materials tested include MgF2 (optimized for highest performance from 120-150nm), SiO2 (150-180nm), Al2O3(180-240nm), MgO (200-250nm), and HfO2 (240-300nm). A variety of deposition techniques were tested and a selection of coatings which minimized reflectance on a Si test wafer were applied to live devices. We also d...

  8. A Metasurface Anti-reflection Coating for Enhancing Surface Plasmon-Polariton of Metallic Hole Array

    Science.gov (United States)

    Bhattarai, Khagendra; Jeon, Jiyeon; Kim, Jun; Ku, Zahyun; Lee, Sang Jun; Zhou, Jiangfeng; Usf, Usa Collaboration; Kriss, Korea Collaboration; Afrl, Usa Collaboration

    We demonstrate a metasurface made of metallic disk resonator array as an anti-reflection (AR) coating to enhance (reduce) the transmission (reflection) through metal hole array (MHA). Our result show that the simulated (measured) transmission at the first order surface plasmon-polariton (SPP) resonance is increased up to 82 %(88%) compared to uncoated MHA. The electric field of the surface wave is also enhanced by 33%. Using an effective medium theory, we show that the metasurface operates at off-resonance wavelengths and can be understood as a thin film that exhibits high effective permittivity (~30) with very low loss (loss tangent ~0.005). Thus we reveal the mechanism of the metasurface AR coating as the traditional thin film AR coating. With tunable effective permittivity, our structure provides great flexibility to achieve AR coating for general substance at any wavelength.

  9. High durability antireflection coatings for silicon and multispectral ZnS

    Science.gov (United States)

    Joseph, Shay; Marcovitch, Orna; Yadin, Ygal; Klaiman, Dror; Koren, Nitzan; Zipin, Hedva

    2007-04-01

    In the current complex battle field, military platforms are required to operate on land, at sea and in the air in all weather conditions both day and night. In order to achieve such capabilities, advanced electro-optical systems are being constantly developed and improved. These systems such as missile seeker heads, reconnaissance and target acquisition pods and tracking, monitoring and alert systems have external optical components (window or dome) which must remain operational even at extreme environmental conditions. Depending on the intended use of the system, there are a few choices of window and dome materials. Amongst the more common materials one can point out sapphire, ZnS, germanium and silicon. Other materials such as spinel, ALON and yittria may also be considered. Most infrared materials have high indices of refraction and therefore they reflect a large part of radiation. To minimize the reflection and increase the transmission, antireflection (AR) coatings are the most common choice. Since these systems operate at different environments and weather conditions, the coatings must be made durable to withstand these extreme conditions. In cases where the window or dome is made of relatively soft materials such as multispectral ZnS, the coating may also serve as protection for the window or dome. In this work, several antireflection coatings have been designed and manufactured for silicon and multispectral ZnS. The coating materials were chosen to be either oxides or fluorides which are known to have high durability. Ellipsometry measurements were used to characterize the optical constants of the thin films. The effects of the deposition conditions on the optical constants of the deposited thin films and durability of the coatings will be discussed. The coatings were tested according to MIL-STD-810E and were also subjected to rain erosion tests at the University of Dayton Research Institute (UDRI) whirling arm apparatus in which one of the coatings showed

  10. Broadband antireflective silicon nanostructures produced by spin-coated Ag nanoparticles.

    Science.gov (United States)

    Kim, Joon Beom; Yeo, Chan Il; Lee, Yong Hwan; Ravindran, Sooraj; Lee, Yong Tak

    2014-01-01

    We report the fabrication of broadband antireflective silicon (Si) nanostructures fabricated using spin-coated silver (Ag) nanoparticles as an etch mask followed by inductively coupled plasma (ICP) etching process. This fabrication technique is a simple, fast, cost-effective, and high-throughput method, making it highly suitable for mass production. Prior to the fabrication of Si nanostructures, theoretical investigations were carried out using a rigorous coupled-wave analysis method in order to determine the effects of variations in the geometrical features of Si nanostructures to obtain antireflection over a broad wavelength range. The Ag ink ratio and ICP etching conditions, which can affect the distribution, distance between the adjacent nanostructures, and height of the resulting Si nanostructures, were carefully adjusted to determine the optimal experimental conditions for obtaining desirable Si nanostructures for practical applications. The Si nanostructures fabricated using the optimal experimental conditions showed a very low average reflectance of 8.3%, which is much lower than that of bulk Si (36.8%), as well as a very low reflectance for a wide range of incident angles and different polarizations over a broad wavelength range of 300 to 1,100 nm. These results indicate that the fabrication technique is highly beneficial to produce antireflective structures for Si-based device applications requiring low light reflection. PMID:24484636

  11. Performance of "Moth Eye" Anti-Reflective Coatings for Solar Cell Applications

    Energy Technology Data Exchange (ETDEWEB)

    Clark, E.; Kane, M.; Jiang, P.

    2011-03-14

    An inexpensive, effective anti-reflective coating (ARC) has been developed at the University of Florida to significantly enhance the absorption of light by silicon in solar cells. This coating has nano-scale features, and its microstructure mimics that of various night active insects (e.g. a moth's eye). It is a square array of pillars, each about 700 nm high and having a diameter of about 300 nm. Samples of silicon having this coating were exposed either to various combinations of either elevated temperature and humidity or to gamma irradiation ({sup 60}Co) at the Savannah River National Laboratory, or to a broad spectrum ultraviolet light and to a 532 nm laser light at the University of Florida. The anti-reflective properties of the coatings were unaffected by any of these environmental stresses, and the microstructure of the coating was also unaffected. In fact, the reflectivity of the gamma irradiated ARC became lower (advantageous for solar cell applications) at wavelengths between 400 and 1000 nm. These results show that this coating is robust and should be tested in actual systems exposed to either weather or a space environment. Structural details of the ARCs were studied to optimize their performance. Square arrays performed better than hexagonal arrays - the natural moth-eye coating is indeed a square array. The optimal depth of the templated nanopillars in the ARC was investigated. A wet etching technology for ARC formation was developed that would be less expensive and much faster than dry etching. Theoretical modeling revealed that dimple arrays should perform better than nipple arrays. A method of fabricating both dimple and nipple arrays having the same length was developed, and the dimple arrays performed better than the nipple arrays, in agreement with the modeling. The commercial viability of the technology is quite feasible, since the technology is scalable and inexpensive. This technology is also compatible with current industrial

  12. Atomic Layer Deposition of Chemical Passivation Layers and High Performance Anti-Reflection Coatings on Back-Illuminated Detectors

    Science.gov (United States)

    Hoenk, Michael E. (Inventor); Greer, Frank (Inventor); Nikzad, Shouleh (Inventor)

    2014-01-01

    A back-illuminated silicon photodetector has a layer of Al2O3 deposited on a silicon oxide surface that receives electromagnetic radiation to be detected. The Al2O3 layer has an antireflection coating deposited thereon. The Al2O3 layer provides a chemically resistant separation layer between the silicon oxide surface and the antireflection coating. The Al2O3 layer is thin enough that it is optically innocuous. Under deep ultraviolet radiation, the silicon oxide layer and the antireflection coating do not interact chemically. In one embodiment, the silicon photodetector has a delta-doped layer near (within a few nanometers of) the silicon oxide surface. The Al2O3 layer is expected to provide similar protection for doped layers fabricated using other methods, such as MBE, ion implantation and CVD deposition.

  13. Millimeter-Wave Broadband Anti-Reflection Coatings Using Laser Ablation of Sub-Wavelength Structures

    CERN Document Server

    Matsumura, Tomotake; Wen, Qi; Hanany, Shaul; Koch, Jürgen; Suttman, Oliver; Schütz, Viktor

    2016-01-01

    We report on the first use of laser ablation to make sub-millimeter, broad-band, anti-reflection coatings (ARC) based on sub-wavelength structures (SWS) on alumina and sapphire. We used a 515 nm laser to produce pyramid-shaped structures with pitch of about 320 \\mu m and total height of near 800 \\mu m. Transmission measurements between 70 and 140 GHz are in agreement with simulations using electromagnetic propagation software. The simulations indicate that SWS ARC with the fabricated shape should have a fractional bandwidth response of $\\Delta \

  14. Antireflective coatings for multijunction solar cells under wide-angle ray bundles.

    Science.gov (United States)

    Victoria, Marta; Domínguez, César; Antón, Ignacio; Sala, Gabriel

    2012-03-26

    Two important aspects must be considered when optimizing antireflection coatings (ARCs) for multijunction solar cells to be used in concentrators: the angular light distribution over the cell created by the particular concentration system and the wide spectral bandwidth the solar cell is sensitive to. In this article, a numerical optimization procedure and its results are presented. The potential efficiency enhancement by means of ARC optimization is calculated for several concentrating PV systems. In addition, two methods for ARCs direct characterization are presented. The results of these show that real ARCs slightly underperform theoretical predictions. PMID:22453483

  15. Millimeter-Wave Broadband Anti-Reflection Coatings Using Laser Ablation of Sub-Wavelength Structures

    OpenAIRE

    Matsumura, Tomotake; Young, Karl; Wen, Qi; Hanany, Shaul; Ishino, Hirokazu; Inoue, Yuki; Hazumi, Masashi; Koch, Jürgen; Suttman, Oliver; Schütz, Viktor

    2016-01-01

    We report on the first use of laser ablation to make sub-millimeter, broad-band, anti-reflection coatings (ARC) based on sub-wavelength structures (SWS) on alumina and sapphire. We used a 515 nm laser to produce pyramid-shaped structures with pitch of about 320 $\\mu$m and total height of near 800 $\\mu$m. Transmission measurements between 70 and 140 GHz are in agreement with simulations using electromagnetic propagation software. The simulations indicate that SWS ARC with the fabricated shape ...

  16. Influence of window layer thickness on double layer antireflection coating for triple junction solar cells

    International Nuclear Information System (INIS)

    The optimization of a SiO2/TiO2, SiO2/ZnS double layer antireflection coating (ARC) on Ga0.5In0.5P/In0.02Ga0.98As/Ge solar cells for terrestrial application is discussed. The Al0.5In0.5P window layer thickness is also taken into consideration. It is shown that the optimal parameters of double layer ARC vary with the thickness of the window layer. (semiconductor technology)

  17. Millimeter-wave broadband antireflection coatings using laser ablation of subwavelength structures

    Science.gov (United States)

    Matsumura, Tomotake; Young, Karl; Wen, Qi; Hanany, Shaul; Ishino, Hirokazu; Inoue, Yuki; Hazumi, Masashi; Koch, Jürgen; Suttman, Oliver; Schütz, Viktor

    2016-05-01

    We report on the first use of laser ablation to make sub-millimeter, broad-band, anti-reflection coatings (ARC) based on sub-wavelength structures (SWS) on alumina and sapphire. We used a 515 nm laser to produce pyramid-shaped structures with pitch of about 320 $\\mu$m and total height of near 800 $\\mu$m. Transmission measurements between 70 and 140 GHz are in agreement with simulations using electromagnetic propagation software. The simulations indicate that SWS ARC with the fabricated shape should have a fractional bandwidth response of $\\Delta \

  18. Antireflective bilayer coatings based on Al2O3 film for UV region

    OpenAIRE

    Marszałek Konstanty; Winkowski Paweł; Marszałek Marta

    2015-01-01

    Bilayer antireflective coatings consisting of aluminium oxide Al2O3/MgF2 and Al2O3/SiO2 are presented in this paper. Oxide films were deposited by means of e-gun evaporation in vacuum of 5 × 10-3 Pa in the presence of oxygen, and magnesium fluoride was prepared by thermal evaporation on heated optical lenses made from quartz glass (Corning HPFS). Substrate temperature was maintained at 250 _C during the deposition. Thickness and deposition rate were controlled with a thickness measuring syste...

  19. Antireflectance coating on shielding window glasses using glacial acetic acid at ambient temperature

    International Nuclear Information System (INIS)

    High density lead glasses having thickness of several centimeters and large dimensions are used as shielding windows in hot cells. To improve visibility, the reflection of light from its optically polished surfaces needs to be minimized to improve transmission as absorption of light in the thick glasses can not be avoided. Antireflectance coating of a material having low refractive index is required for this purpose. Selective leaching of lead at ambient temperature in glacial acetic acid develops a silica rich leached layer on glass surface. Since silica has low refractive index, the leached layer serves as antireflectance coating. Two optically polished discs of shielding window glasses were leached in glacial acetic acid at ambient temperature for 2, 5 and 10 days and their reflectance and transmittance spectra were taken to find effect of leaching. For transparent glass transmittance could be improved from 78.76% to 85.31% after 10 days leaching. Reflectance from the glass could be decreased from 12.48 to 11.67%. For coloured glass transmittance improved from 87.77% to 88.24% after 5 days leaching while reflectance decreased from 12.28% to 5.6% during same period. Based on data generated, 10 days leaching time is recommended for developing anti reflectance coating on transparent shielding window glass and 5 days for coloured shielding window glass. The procedure can be used for shielding windows of any dimensions by fabrication a PVC tank of slightly high dimensions and filling with acetic acid (author)

  20. Solgel derived tantalum pentoxide films as ultraviolet antireflective coatings for silicon.

    Science.gov (United States)

    Rehg, T J; Ochoa-Tapia, J A; Knoesen, A; Higgins, B G

    1989-12-15

    A solgel process is described to produce Ta(2)O(5) films as short wavelength antireflective (AR) coatings for silicon. The AR coatings were optimized for 370 nm by controlling the acid catalyzed hydrolysis of Ta(OC(2)H(5))(5), the spin coating parameters, and the heat treatment process (rapid thermal processing (RTP) and muffle furnace). Film thickness uniformity across the wafer was better than 1%, and all the coatings tested passed the standard scotch tape test before and after heat treatment and exhibited no change in optical properties after submersion in liquid N(2). Several heat treatment protocols for densifying the films were studied. Spin coated films heat treated in a muffle furnace at 275 degrees C yielded Ta(2)O(5) AR coatings that reduced the reflectance losses from silicon at 370 nm by 86%, the reduction being within 1% of the theoretical value. Films subjected to RTP at temperatures ranging from 300 to 1000 degrees C reduced the reflectance loss in some cases by as much as 95%. The results demonstrate that spin coated solgel derived Ta(2)O(5) films subjected to a low temperature (coatings for high index silicon devices, such as charge couple imagers and photovoltaic cells. PMID:20556030

  1. Broadband Plasma-Sprayed Anti-reflection Coating for Millimeter-Wave Astrophysics Experiments

    Science.gov (United States)

    Jeong, O.; Lee, A.; Raum, C.; Suzuki, A.

    2016-08-01

    We have developed a plasma-sprayed anti-reflection (AR) coating technology for millimeter-wave astrophysics experiments with cryogenic optics which achieves minimal dissipative loss and broad bandwidth and is easily and accurately applied. Plasma spraying is a coating process through which melted or heated materials are sprayed onto a substrate. The dielectric constants of the plasma-sprayed coatings were tuned between 2.7 and 7.9 by mixing hollow ceramic microspheres with alumina powder as the base material and varying the plasma energy of the spray. By spraying low loss ceramic materials with a tunable dielectric constant, we can apply multiple layers of AR coating for broadband millimeter-wave detection. At 300 K, we achieved a fractional bandwidth of 106 over 90% transmission using a three-layer AR coating. Applying ceramic coatings on ceramic lenses offers an additional benefit of preventing cryogenic delamination of the coatings. We report on methodology of coating application and measurement of uniformity, repeatability, transmission property, and cryogenic adhesion performance.

  2. Broadband Plasma-Sprayed Anti-reflection Coating for Millimeter-Wave Astrophysics Experiments

    Science.gov (United States)

    Jeong, O.; Lee, A.; Raum, C.; Suzuki, A.

    2016-02-01

    We have developed a plasma-sprayed anti-reflection (AR) coating technology for millimeter-wave astrophysics experiments with cryogenic optics which achieves minimal dissipative loss and broad bandwidth and is easily and accurately applied. Plasma spraying is a coating process through which melted or heated materials are sprayed onto a substrate. The dielectric constants of the plasma-sprayed coatings were tuned between 2.7 and 7.9 by mixing hollow ceramic microspheres with alumina powder as the base material and varying the plasma energy of the spray. By spraying low loss ceramic materials with a tunable dielectric constant, we can apply multiple layers of AR coating for broadband millimeter-wave detection. At 300 K, we achieved a fractional bandwidth of 106 over 90% transmission using a three-layer AR coating. Applying ceramic coatings on ceramic lenses offers an additional benefit of preventing cryogenic delamination of the coatings. We report on methodology of coating application and measurement of uniformity, repeatability, transmission property, and cryogenic adhesion performance.

  3. Characterization of Silicon Moth-Eye Antireflection Coatings for Astronomical Applications in the Infrared

    Science.gov (United States)

    Jeram, Sarik; Ge, Jian; Jiang, Peng; Phillips, Blayne

    2016-01-01

    Silicon moth-eye antireflective structures have emerged to be an excellent approachfor reducing the amount of light that is lost upon incidence on a given surface of optics made of silicon. This property has been exploited for a wide variety of products ranging from eyeglasses and flat-panel displays to solar panels. These materials typically come in the form of coatings that are applied to an optical substrate such as glass. Moth-eye coatings, made of a periodic array of subwavelength pillars on silicon substrates or other substrates, can produce the desired antireflection (AR) performance for a broad wavelength range and over a wide range of incident angles. In the field of astronomy, every photon striking a detector is significant - and thus, losses from reflectivity at the various optical interfaces before a detector can have significant implications to the science at hand. Moth-eye AR coatings on these optical interfaces may minimize their reflection losses while maximizing light throughput for a multitude of different astronomical instruments. In addition, moth-eye AR coatings, which are patterned directly on silicon surfaces, can significantly enhance the coating durability. At the University of Florida, we tested two moth-eye filters designed for use in the near-infrared regime at 1-8 microns by examining their optical properties, such as transmission, the scattered light, and wavefront quality, and testing the coatings at cryogenic temperatures to characterize their viability for use in both ground- and space-based infrared instruments. This presentation will report our lab evaluation results.

  4. Advancements in organic antireflective coatings for dual-damascene processes

    Science.gov (United States)

    Deshpande, Shreeram V.; Shao, Xie; Lamb, James E., III; Brakensiek, Nickolas L.; Johnson, Joe; Wu, Xiaoming; Xu, Gu; Simmons, William J.

    2000-06-01

    Dual Damascene (DD) process has been implemented in manufacturing semiconductor devices with smaller feature sizes (EQ 0.20 micrometer), due to increased use of copper as a metal of choice for interconnects. Copper is preferred over aluminum due to its lower resistance which helps to minimize the effects of interconnect delays. Via first DD process is the most commonly used process for manufacturing semiconductor devices since it requires less number of processing steps and also it can make use of a via fill material to minimize the resist thickness variations in the trench patterning photolithography step. Absence of via fill material results in non-uniform fill of vias (in isolated and dense via regions) thus leading to non-uniform focus and dose for exposure of the resist in the deep vias. This results in poor resolution and poor critical dimension (CD) control in the trench-patterning step. When a via fill organic material such as a bottom anti- reflective coating (BARC) is used, then the resist thickness variations are minimized thus enhancing the resolution and CD control in trench patterning. Via fill organic BARC materials can also act as etch blocks at the base of the via to protect the substrate from over etch. In this paper we review the important role of via fill organic BARCs in improving the efficiency of via first DD process now being implemented in semiconductor manufacturing.

  5. Layer-by-Layer-Assembled High-Performance Broadband Antireflection Coatings

    KAUST Repository

    Shimomura, Hiroomi

    2010-03-24

    Nanoparticles are indispensable ingredients of solution-processed optical, dielectric, and catalytic thin films. Although solution-based methods are promising low-cost alternatives to vacuum methods, they can have significant limitations. Coating uniformity, thickness control, roughness control, mechanical durability, and incorporation of a diverse set of functional organic molecules into nanoparticle thin films are major challenges. We have used the electrostatic layer-by-layer assembly technique to make uniform, conformal multistack nanoparticle thin films for optical applications with precise thickness control over each stack. Two particularly sought-after optical applications are broadband antireflection and structural color. The effects of interstack and surface roughness on optical properties of these constructs (e.g., haze and spectral response) have been studied quantitatively using a combination of Fourier-transform methods and atomic force microscopy measurements. Deconvoluting root-mean-square roughness into its large-, intermediate-, and small-scale components enables enhanced optical simulations. A 4-stack broadband antireflection coating (<0.5% average reflectance in the visible range, and 0.2% haze) composed of alternating high-index (n ≈ 1.96) and low-index (n ≈ 1.28) stacks has been made on glass substrate. Films calcinated at 550 °C endure a one-hour-long cloth cleaning test under 100 kPa normal stress. © 2010 American Chemical Society.

  6. Novel conformal organic antireflective coatings for advanced I-line lithography

    Science.gov (United States)

    Deshpande, Shreeram V.; Nowak, Kelly A.; Fowler, Shelly; Williams, Paul; Arjona, Mikko

    2001-08-01

    Flash memory chips are playing a critical role in semiconductor devices due to increased popularity of hand held electronic communication devices such as cell phones and PDAs (personal Digital Assistants). Flash memory offers two primary advantages in semiconductor devices. First, it offers flexibility of in-circuit programming capability to reduce the loss from programming errors and to significantly reduce commercialization time to market for new devices. Second, flash memory has a double density memory capability through stacked gate structures which increases the memory capability and thus saves significantly on chip real estate. However, due to stacked gate structures the requirements for manufacturing of flash memory devices are significantly different from traditional memory devices. Stacked gate structures also offer unique challenges to lithographic patterning materials such as Bottom Anti-Reflective Coating (BARC) compositions used to achieve CD control and to minimize standing wave effect in photolithography. To be applicable in flash memory manufacturing a BARC should form a conformal coating on high topography of stacked gate features as well as provide the normal anti-reflection properties for CD control. In this paper we report on a new highly conformal advanced i-line BARC for use in design and manufacture of flash memory devices. Conformal BARCs being significantly thinner in trenches than the planarizing BARCs offer the advantage of reducing BARC overetch and thus minimizing resist thickness loss.

  7. Controlled synthesis and characteristics of antireflection coatings of TiO2 produced from a organometallic colloid

    International Nuclear Information System (INIS)

    Highlights: → Titanium dioxide antireflection coating was made by a less used titanium colloidal precursor solution. → Sol-gel spin-coating process was used to make thin films on silicon substrates. → Various process parameters have been studied and their effect on physical, structural and optical properties was investigated. → Application of the coating on silicon solar cells showed an enhancement more than 20% in Jsc in comparison to the cell devoid of the coating. - Abstract: Antireflection titanium dioxide (TiO2) coatings have been developed on monocrystalline silicon by a sol-gel spin-coating process using titanium di-isopropoxidebis(acetylacetonate) colloidal precursor solution. The effect of titanium content in the precursor, spin rate, sintering duration and temperature have been studied and their effect on coating thickness and optical properties (i.e., refractive index and reflectivity) were investigated. The influence of post-deposition sintering temperature on the optical characteristics, composition and the microstructure of the coatings have been evaluated by UV-vis spectroscopy, ellipsometry, X-ray photoelectron spectroscopy, atomic force microscopy and X-ray diffraction techniques. Solar cells made on silicon wafers with TiO2 as antireflection layer showed enhancement of more than 20% in short circuit current density in comparison to a cell devoid of the TiO2 coating.

  8. A New Artificial Dielectric Metamaterial and its Application as a THz Anti-Reflection Coating

    CERN Document Server

    Zhang, Jin; Mauskopf, Philip; Moncelsi, Lorenzo; Savini, Giorgio; Whitehouse, Nicola; 10.1364/AO.48.006635

    2011-01-01

    We describe a novel artificial dielectric material which has applications at millimetre and submillimetre wavelengths. The material is manufactured from layers of metal mesh patterned onto thin polypropylene sheets which are then bonded together using a hot pressing process to provide planar rugged discs which can be reliably cycled to cryogenic temperatures. The refractive index of this material can be tuned by adjusting the geometry and spacing of the metal-mesh layers. We demonstrate its usage by designing and characterising a broadband anti-reflection coating for a Z-cut crystalline Quartz plate. The coating was fabricated and applied to the quartz using the hot press technique and characterized using a Fourier Transform Spectrometer. The performance is shown to be in good agreement with HFSS and transmission line modelling results.

  9. Surface structured optical coatings with near-perfect broadband and wide-angle antireflective properties.

    Science.gov (United States)

    Perl, Emmett E; McMahon, William E; Farrell, Robert M; DenBaars, Steven P; Speck, James S; Bowers, John E

    2014-10-01

    Optical thin-film coatings are typically limited to designs where the refractive index varies in only a single dimension. However, additional control over the propagation of incoming light is possible by structuring the other two dimensions. In this work, we demonstrate a three-dimensional surface structured optical coating that combines the principles of thin-film optical design with bio-inspired nanostructures to yield near-perfect antireflection. Using this hybrid approach, we attain average reflection losses of 0.2% on sapphire and 0.6% on gallium nitride for 300-1800 nm light. This performance is maintained to very wide incidence angles, achieving less than 1% reflection at all measured wavelengths out to 45° for sapphire. This hybrid design has the potential to significantly enhance the broadband and wide-angle properties for a number of optical systems that require high transparency. PMID:25238041

  10. Large-aperture Wide-bandwidth Antireflection-coated Silicon Lenses for Millimeter Wavelengths

    Science.gov (United States)

    Datta, R.; Munson, C. D.; Niemack, M. D.; McMahon, J. J.; Britton, J.; Wollack, Edward J.; Beall, J.; Devlin, M. J.; Fowler, J.; Gallardo, P.; Hubmayr, J.; Irwin, K.; Newburgh, L.; Nibarger, J. P.; Page, L.; Quijada, Manuel A.; Schmitt, B. L.; Staggs, S. T.; Thornton, R.; Zhang, L.

    2013-01-01

    The increasing scale of cryogenic detector arrays for submillimeter and millimeter wavelength astrophysics has led to the need for large aperture, high index of refraction, low loss, cryogenic refracting optics. Silicon with n 3.4, low loss, and high thermal conductivity is a nearly optimal material for these purposes but requires an antireflection (AR) coating with broad bandwidth, low loss, low reflectance, and a matched coefficient of thermal expansion. We present an AR coating for curved silicon optics comprised of subwavelength features cut into the lens surface with a custom three-axis silicon dicing saw. These features constitute a metamaterial that behaves as a simple dielectric coating.We have fabricated silicon lenses as large as 33.4 cm in diameter with micromachined layers optimized for use between 125 and 165 GHz. Our design reduces average reflections to a few tenths of a percent for angles of incidence up to 30deg with low cross polarization.We describe the design, tolerance, manufacture, and measurements of these coatings and present measurements of the optical properties of silicon at millimeter wavelengths at cryogenic and room temperatures. This coating and lens fabrication approach is applicable from centimeter to submillimeter wavelengths and can be used to fabricate coatings with greater than octave bandwidth.

  11. Anti-Reflective and Waterproof Hard Coating for High Power Laser Optical Elements

    Science.gov (United States)

    Murahara, Masataka; Yabe, Takashi; Uchida, Shigeaki; Yoshida, Kunio; Okamoto, Yoshiaki

    2006-05-01

    A hard coating method of single crystalline porous silica film is widely used for high power laser optical elements in the air. However, there is no protective hard coating method for the elements to survive high power laser irradiance while in the water. We, thus, developed a new method for a waterproof coating with photo-oxidation of silicone oil. The silicone oil was spin-coated onto the surface of optical elements, and then irradiated with a xenon excimer lamp in the air. In this treatment, a protective coating for plastic lenses, mirrors, and nonlinear optical crystals, which are highly deliquescent, was developed by taking advantage of the phenomenon in which organic silicone oil is transformed to inorganic amorphous glass by a process of photo-oxidation. This technique has enabled an optical thin coating film to transmit ultraviolet rays of wavelengths under 200 nm and possess the characteristics of homogeneity, high density, resistance to environment, anti-reflectiveness, resistance to water, and Mohs' scale of 5, which is comparable to apatite. This allows us to cool a slab laser head and use as a mirror for underwater laser welding.

  12. Large-aperture wide-bandwidth antireflection-coated silicon lenses for millimeter wavelengths

    CERN Document Server

    Datta, R; Niemack, M D; McMahon, J J; Britton, J; Wollack, E J; Beall, J; Devlin, M J; Fowler, J; Gallardo, P; Hubmayr, J; Irwin, K; Newburgh, L; Nibarger, J P; Page, L; Quijada, M A; Schmitt, B L; Staggs, S T; Thornton, R; Zhang, L

    2013-01-01

    The increasing scale of cryogenic detector arrays for sub-millimeter and millimeter wavelength astrophysics has led to the need for large aperture, high index of refraction, low loss, cryogenic refracting optics. Silicon with n = 3.4, low loss, and relatively high thermal conductivity is a nearly optimal material for these purposes, but requires an antireflection (AR) coating with broad bandwidth, low loss, low reflectance, and a matched coefficient of thermal expansion. We present an AR coating for curved silicon optics comprised of subwavelength features cut into the lens surface with a custom three axis silicon dicing saw. These features constitute a metamaterial that behaves as a simple dielectric coating. We have fabricated and coated silicon lenses as large as 33.4 cm in diameter with coatings optimized for use between 125-165 GHz. Our design reduces average reflections to a few tenths of a percent for angles of incidence up to 30 degrees with low cross-polarization. We describe the design, tolerance, m...

  13. Evaporation of uniform antireflection coatings on hemispherical lenses to enhance infrared antenna gain

    Science.gov (United States)

    Slovick, Brian A.; Krenz, Peter M.; Zummo, Guy; Boreman, Glenn D.

    2010-03-01

    Infrared dipole-coupled bolometers receive radiation more efficiently when illuminated through a high permittivity, antireflection (AR) coated, hemispherical immersion lens. To maintain the enhanced responsivity for all illumination angles, the AR coating must be uniform over the hemispherical surface. An evaporation method for depositing a uniform AR coating on the hemispherical surface is presented. The lens is tilted relative to the source, which can be either electron-beam or thermal, and rotated throughout the deposition. Evaporation at an angle of 70° yields a uniform film with less than 10% thickness variation over a 120° full angle of the hemispherical surface. A theoretical model is developed and compared to profilometer measurements. In all cases, there is general agreement between theory and measurement. A single dipole is fabricated onto the flat surface of an AR-coated germanium immersion lens and the responsivity is measured for both substrate-side and air-side illumination. With a zinc sulfide (ZnS) single-layer AR coating, substrate-side illumination yields a broadside antenna response 49 ± 2.7 times greater than air-side illumination.

  14. Multispectral antireflection coating simultaneously effective in visible, diode laser, Nd-YAG and eye safe laser wavelength

    International Nuclear Information System (INIS)

    Multi-spectral antireflection coating effective in visible region for sighting system, Nd-YAG laser wavelength for designator/seeker system, both diode laser and eye safe laser wavelength for ranging purpose can use common objective/receiver optics highly useful for state of art laser instrumentation. In this paper, design and fabrication of antireflection coating simultaneously effective in visible region (500 to 650nm), diode laser at 904±25nm and Nd-YAG laser at 1064±25nm, and erbium-glass laser wavelength at 1540±25nm has been reported. Inhomogeneous refractive index profile as suggested by Southwell was used to design this coating. The inhomogeneous profile was then approximated with eleven steps from substrate to air medium in order to obtain desirable antireflection property in the visible and laser wavelengths. These steps were then converted into the available coating materials (titanium-di-oxide and magnesium fluoride) of twenty-two layer stack. The multilayer stack was fabricated by using electron beam gun evaporation system in Balzers BAK-600 vacuum coating unit. The result achieved were less than 2% average reflection (98% average transmission) from 500 to 650nm, 1.5% reflection (98.5% average transmission) at 904nm, 1064nm and 1540nm. The coated samples successfully passed the specifications of MIL-C-14806 tests

  15. Bright Single-Photon Sources Based on Anti-Reflection Coated Deterministic Quantum Dot Microlenses

    Directory of Open Access Journals (Sweden)

    Peter Schnauber

    2015-12-01

    Full Text Available We report on enhancing the photon-extraction efficiency (PEE of deterministic quantum dot (QD microlenses via anti-reflection (AR coating. The AR-coating deposited on top of the curved microlens surface is composed of a thin layer of Ta2O5, and is found to effectively reduce back-reflection of light at the semiconductor-vacuum interface. A statistical analysis of spectroscopic data reveals, that the AR-coating improves the light out-coupling of respective microlenses by a factor of 1.57 ± 0.71, in quantitative agreement with numerical calculations. Taking the enhancement factor into account, we predict improved out-coupling of light with a PEE of up to 50%. The quantum nature of emission from QDs integrated into AR-coated microlenses is demonstrated via photon auto-correlation measurements revealing strong suppression of two-photon emission events with g(2(0 = 0.05 ± 0.02. As such, these bright non-classical light sources are highly attractive with respect to applications in the field of quantum cryptography.

  16. An experimental study of antireflective coatings in Ge light detectors for scintillating bolometers

    Science.gov (United States)

    Mancuso, M.; Beeman, J. W.; Giuliani, A.; Dumoulin, L.; Olivieri, E.; Pessina, G.; Plantevin, O.; Rusconi, C.; Tenconi, M.

    2014-01-01

    Luminescent bolometers are double-readout devices able to measure simultaneously the phonon and the light yields after a particle interaction in the detector. This operation allows in some cases to tag the type of the interacting quantum, crucial issue for background control in rare event experiments such as the search for neutrinoless double beta decay and for interactions of particle dark matter candidates. The light detectors used in the LUCIFER and LUMINEU searches (projects aiming at the study of the double beta interesting candidates 82Se and 100Mo using ZnSe and ZnMoO4 scintillating bolometers) consist of hyper-pure Ge thin slabs equipped with NTD thermistors. A substantial sensitivity improvement of the Ge light detectors can be obtained applying a proper anti-reflective coatings on the Ge side exposed to the luminescent bolometer. The present paper deals with the investigation of this aspect, proving and quantifying the positive effect of a SiO2 and a SiO coating and setting the experimental bases for future tests of other coating materials. The results confirm that an appropriate coating procedure helps in improving the sensitivity of bolometric light detectors by an important factor (in the range 20% - 35%) and needs to be included in the recipe for the development of an optimized radio-pure scintillating bolometer.

  17. Titanium dioxide antireflection coating for silicon solar cells by spray deposition

    Science.gov (United States)

    Kern, W.; Tracy, E.

    1980-01-01

    A high-speed production process is described for depositing a single-layer, quarter-wavelength thick antireflection coating of titanium dioxide on metal-patterned single-crystal silicon solar cells for terrestrial applications. Controlled atomization spraying of an organotitanium solution was selected as the most cost-effective method of film deposition using commercial automated equipment. The optimal composition consists of titanium isopropoxide as the titanium source, n-butyl acetate as the diluent solvent, sec-butanol as the leveling agent, and 2-ethyl-1-hexanol to render the material uniformly depositable. Application of the process to the coating of circular, large-diameter solar cells with either screen-printed silver metallization or with vacuum-evaporated Ti/Pd/Ag metallization showed increases of over 40% in the electrical conversion efficiency. Optical characteristics, corrosion resistance, and several other important properties of the spray-deposited film are reported. Experimental evidence indicates a wide tolerance in the coating thickness upon the overall efficiency of the cell. Considerations pertaining to the optimization of AR coatings in general are discussed, and a comprehensive critical survey of the literature is presented.

  18. An experimental study of antireflective coatings in Ge light detectors for scintillating bolometers

    Directory of Open Access Journals (Sweden)

    Mancuso M.

    2014-01-01

    Full Text Available Luminescent bolometers are double-readout devices able to measure simultaneously the phonon and the light yields after a particle interaction in the detector. This operation allows in some cases to tag the type of the interacting quantum, crucial issue for background control in rare event experiments such as the search for neutrinoless double beta decay and for interactions of particle dark matter candidates. The light detectors used in the LUCIFER and LUMINEU searches (projects aiming at the study of the double beta interesting candidates 82Se and 100Mo using ZnSe and ZnMoO4 scintillating bolometers consist of hyper-pure Ge thin slabs equipped with NTD thermistors. A substantial sensitivity improvement of the Ge light detectors can be obtained applying a proper anti-reflective coatings on the Ge side exposed to the luminescent bolometer. The present paper deals with the investigation of this aspect, proving and quantifying the positive effect of a SiO2 and a SiO coating and setting the experimental bases for future tests of other coating materials. The results confirm that an appropriate coating procedure helps in improving the sensitivity of bolometric light detectors by an important factor (in the range 20% – 35% and needs to be included in the recipe for the development of an optimized radio-pure scintillating bolometer.

  19. Highly transparent triboelectric nanogenerator for harvesting water-related energy reinforced by antireflection coating

    Science.gov (United States)

    Liang, Qijie; Yan, Xiaoqin; Gu, Yousong; Zhang, Kui; Liang, Mengyuan; Lu, Shengnan; Zheng, Xin; Zhang, Yue

    2015-03-01

    Water-related energy is an inexhaustible and renewable energy resource in our environment, which has huge amount of energy and is not largely dictated by daytime and sunlight. The transparent characteristic plays a key role in practical applications for some devices designed for harvesting water-related energy. In this paper, a highly transparent triboelectric nanogenerator (T-TENG) was designed to harvest the electrostatic energy from flowing water. The instantaneous output power density of the T-TENG is 11.56 mW/m2. Moreover, with the PTFE film acting as an antireflection coating, the maximum transmittance of the fabricated T-TENG is 87.4%, which is larger than that of individual glass substrate. The T-TENG can be integrated with silicon-based solar cell, building glass and car glass, which demonstrates its potential applications for harvesting waste water energy in our living environment and on smart home system and smart car system.

  20. Indium doped zinc oxide nanowire thin films for antireflection and solar absorber coating applications

    Energy Technology Data Exchange (ETDEWEB)

    Shaik, Ummar Pasha [ACRHEM, University of Hyderabad, Hyderabad-500046 (India); Krishna, M. Ghanashyam, E-mail: mgksp@uohyd.ac.in [ACRHEM and School of Physics, University of Hyderabad, Hyderabad-500046 (India)

    2014-04-24

    Indium doped ZnO nanowire thin films were prepared by thermal oxidation of Zn-In metal bilayer films at 500°C. The ZnO:In nanowires are 20-100 nm in diameter and several tens of microns long. X-ray diffraction patterns confirm the formation of oxide and indicate that the films are polycrystalline, both in the as deposited and annealed states. The transmission which is <2% for the as deposited Zn-In films increases to >90% for the ZnO:In nanowire films. Significantly, the reflectance for the as deposited films is < 10% in the region between 200 to 1500 nm and < 2% for the nanowire films. Thus, the as deposited films can be used solar absorber coatings while the nanowire films are useful for antireflection applications. The growth of nanowires by this technique is attractive since it does not involve very high temperatures and the use of catalysts.

  1. Characterization and simulation on antireflective coating of amorphous silicon oxide thin films with gradient refractive index

    Science.gov (United States)

    Huang, Lu; Jin, Qi; Qu, Xingling; Jin, Jing; Jiang, Chaochao; Yang, Weiguang; Wang, Linjun; Shi, Weimin

    2016-08-01

    The optical reflective properties of silicon oxide (SixOy) thin films with gradient refractive index are studied both theoretically and experimentally. The thin films are widely used in photovoltaic as antireflective coatings (ARCs). An effective finite difference time domain (FDTD) model is built to find the optimized reflection spectra corresponding to structure of SixOy ARCs with gradient refractive index. Based on the simulation analysis, it shows the variation of reflection spectra with gradient refractive index distribution. The gradient refractive index of SixOy ARCs can be obtained in adjustment of SiH4 to N2O ratio by plasma-enhanced chemical vapor deposition (PECVD) system. The optimized reflection spectra measured by UV-visible spectroscopy confirms to agree well with that simulated by FDTD method.

  2. Millimeter-wave broadband antireflection coatings using laser ablation of subwavelength structures.

    Science.gov (United States)

    Matsumura, Tomotake; Young, Karl; Wen, Qi; Hanany, Shaul; Ishino, Hirokazu; Inoue, Yuki; Hazumi, Masashi; Koch, Jürgen; Suttman, Oliver; Schütz, Viktor

    2016-05-01

    We report on the first use of laser ablation to make submillimeter, broadband, antireflection coatings (ARCs) based on subwavelength structures (SWSs) on alumina and sapphire. We used a 515 nm laser to produce pyramid-shaped structures with a pitch of about 320 μm and a total height of near 800 μm. Transmission measurements between 70 and 140 GHz are in agreement with simulations using electromagnetic propagation software. The simulations indicate that SWS-ARCs with the fabricated shape should have a fractional bandwidth response of Δν/νcenter=0.55 centered on 235 GHz for which reflections are below 3%. Extension of the bandwidth to both lower and higher frequencies, between a few tens of gigahertz and a few terahertz, should be straightforward with appropriate adjustment of laser ablation parameters. PMID:27140362

  3. New generation of bottom anti-reflective coatings (BARCs): photodefinable BARCs

    Science.gov (United States)

    Guerrero, Douglas J.; Trudgeon, Tonya

    2003-06-01

    Three polymer systems, polycarbonates, polysulfonyl esters, and hybrid carbonate-sulfones, were evaluated as materials for a new generation of bottom anti-reflective coatings (BARCs). The polymers were tested for their solubility in accepted industry solvents, resistance to photoresist solvents after casting, thermal stability, and photosensitivity. From these, polysulfonyl esters show more promising properties as photodefinable BARCs than the other systems because of their good solvent solubility and resistance to photoresist solvents after casting. These polymers can be formulated in ethyl lactate (EL) or 1-methoxy-2-acetoxypropane (PGMEA) but are insoluble in the same solvents after curing above 170°C. The polysulfonyl esters were thermally stable up to ~300°C in air. The cured films were exposed with DUV light at 200 to 600 mJ/cm2. After exposure, the films can be easily removed in alkaline developer.

  4. Laser-induced damage behaviors of antireflective coatings at cryogenic condition.

    Science.gov (United States)

    Wang, He; Zhang, Weili; He, Hongbo

    2012-12-20

    The laser-induced damage to antireflective coatings on Yb:YAG crystals under different temperatures was investigated. An optical profiler, field-emission scanning-electron microscopy, and a step profiler were used to determine the damage morphology, including size and depth. The results show that there is about 5 J/cm(2) decrease in the laser-induced damage threshold of cryogenic conditions compared to that of room temperature in 1-on-1 test mode, and a 3 J/cm(2) decrease in 100-on-1 mode. There is an accumulation effect in both cases. Meanwhile, the damage areas and depths are also much larger under cryogenic conditions. The precipitation of the subsurface defects in the substrate and the thermal stress in the interface between the film and the substrate under cryogenic conditions are considered to be the key factors in the unique damage behaviors. PMID:23262610

  5. Reflectance spectrum of diamond-like carbon/porous silicon double-layer antireflection coatings designed for silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Aroutiounian, V.M.; Martirosyan, Kh.S. [Department of Physics of Semiconductors and Microelectronics, Yerevan State University, 375025 Yerevan (Armenia); Soukiassian, P.G. [Commissariat a l' Energie Atomique, Laboratoire SIMA associe a l' Universite de Paris-Sud/Orsay, DSM/DRECAM/SPCSI, Batiment 462, Saclay, 91191 Gif-sur-Yvette Cedex (France)

    2007-07-01

    In this study, our purpose was to investigate the possibility of using a diamond-like carbon/porous silicon double-layer antireflection coating which is characterized by low reflectance, in order to enhance the performance of silicon solar cells and to protect them from various external influences. Experimental results obtained from reflectance measurements showed the possibility of achieving low reflectance value. Theoretical simulations of the reflectance spectra were carried out. The comparison of the reflectance spectrum of such diamond-like carbon/porous silicon double layer antireflection coating with spectra obtained from other types of coating layers showed a much lower reflectance within larger energy range including the UV, visible and infrared regions of the solar spectrum. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. A moisture-resistant antireflective coating by sol-gel process for neodymium-doped phosphate laser glass

    Institute of Scientific and Technical Information of China (English)

    Ruijun Liu; Ruoyu Zhan; Yongxing Tang; Jianqiang Zhu

    2006-01-01

    @@ Using methyl triethoxysilicane as precursor, a moisture-resistant coating for neodymium-doped laser glass was developed by the sol-gel process. Colloidal silica was added in coating solution as modifier. The refractive index of this coating varied from 1.31 to 1.42. A porous antireflective (AR) silica coating with the index of 1.27 was coated on the moisture-resistant coating surface. The two-layer coating possessed transmission up to 99.1% at wavelength of 966 nm, surface root-mean-square (RMS) roughness of 1.245nm, and roughness of average (RA) of 0.961 nm. In the case of laser of 1053-nm laser wavelength and 1-ns pulse duration, the damage threshold of the two-layer coatings was more than 15 J/cm2.

  7. Broad band antireflection coating on zinc sulphide simultaneously effective in SWIR, MWIR and LWIR regions

    Science.gov (United States)

    Ghosh, A.; Upadhyaya, A. S.

    2009-07-01

    In recent years multi-spectral imagery is steadily growing popularity. Multi-channel imaging which includes short-wave infrared (SWIR), mid-wave infrared (MWIR) and long-wave infrared (LWIR) systems are useful for threat detection, tracking, thermal signature detection and terrain analysis. In this paper, a broad band antireflection coating on ZnS substrate, simultaneously effective in SWIR, MWIR and LWIR is reported. The coating design approach was evolved using gradient index concept, where refractive index varies gradually from incident media to the ZnS ( n = 2.2) substrate. The gradient index profile depicted by 4th degree polynomial n( t) = -0.45 t4 + 1.9 t3 - 2.7 t2 + 1.9 t + 1,where n( t) is the refractive index at the distance t from ambient, and t is the thickness in micron. The profile is best approximated by eight discrete step index layers, whose first layer is thorium fluoride ( n = 1.42; lowest index stable material available). Other seven layers are replaced by two equivalent layer system of real materials thorium fluoride and zinc sulphide. Final 15 layers design is deposited by e-beam evaporation. The maximum layer thickness was restricted around 0.7 μm to overcome the stress problem in the film. This 15 layers coating has shown average transmission 95% in 0.9-10.5 μm spectral band having peak 99% at 9 μm.

  8. Effect of substrate index of refraction on the design of antireflection coatings

    Science.gov (United States)

    Willey, Ronald R.

    2011-09-01

    Formulae to estimate the average percent reflectance (Rave) of a broadband antireflection (AR) coating as a function of the bandwidth (B), the overall thickness (C), the index of refraction of the last layer (L), and the difference between the indices of the high- and low-index layers (D) were reported in 1991. Various refinements of these formulae and other insights into the underlying behavior of such coating designs have been reported up until the present time. Dobrowolski, et al.6 and Tikhonravov, et al.7 have also added independent viewpoints to this subject over this period. In the previous studies, the effects of the index of refraction of the substrate have mostly been ignored and have appeared to be very minor. This study has investigated the influence of the substrate index on the Rave results. It has been found that there seem to be two classes of designs with respect to the effect of substrate index. In the class of "step down" AR designs, there is a significant effect, in the other class, there is no significant effect. Even in the step-down case, there is no effect of substrate index if any and all indices of refraction for the coating materials are available from that of the index of the substrate to the index of the media.

  9. Broadband anti-reflective and water-repellent coatings on glass substrates for self-cleaning photovoltaic cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiaoyu [Functional Nanomaterials Laboratory and Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry (TIPC), Chinese Academy of Sciences, Zhongguancun Donglu 29, Haidianqu, Beijing 100190 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); He, Junhui, E-mail: jhhe@mail.ipc.ac.cn [Functional Nanomaterials Laboratory and Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry (TIPC), Chinese Academy of Sciences, Zhongguancun Donglu 29, Haidianqu, Beijing 100190 (China); Liu, Weiyi [Institute of Optoelectronics, Nankai University, Tianjin 300071 (China)

    2013-07-15

    Graphical abstract: High performance broadband antireflective and water-repellent coatings were fabricated on glass substrates, which can improve the short-circuit current of solar cells as much as 6.6% in comparison with glass substrates without the coatings. - Highlights: • Broadband anti-reflective and water-repellent coatings were fabricated. • Transmittance increased to 99.0%, significantly higher than that of commercial solar glasses. • The performance of standard solar cells with the AR coating was enhanced as much as 6.6%. - Abstract: High performance broadband antireflective (AR) and water-repellent coatings were fabricated on glass substrates by assembly of silica nanoparticles and polyelectrolytes via the layer-by-layer (LbL) assembly technique, followed by calcination and hydrophobic modification. A porous poly(diallyladimethylammonium chloride) (PDDA)/20 nm SiO{sub 2} nanoparticles (S-20) multilayer coating with AR property was prepared first. The maximum transmittance is as high as 99.0%, while that of the glass substrate is only 91.3%. After calcination and hydrophobic modification, the coating became water-repellent while maintaining the good AR property. Such water-repellent AR coatings can improve the short-circuit current of solar cells as much as 6.6% in comparison with glass substrates without the coatings. Scanning electron microscopy (SEM) was used to observe the morphology and thickness of coatings. Transmission spectra and reflection spectra were characterized by UV–vis spectrophotometer. The surface wettability was studied by a contact angle/interface system.

  10. Broadband anti-reflective and water-repellent coatings on glass substrates for self-cleaning photovoltaic cells

    International Nuclear Information System (INIS)

    Graphical abstract: High performance broadband antireflective and water-repellent coatings were fabricated on glass substrates, which can improve the short-circuit current of solar cells as much as 6.6% in comparison with glass substrates without the coatings. - Highlights: • Broadband anti-reflective and water-repellent coatings were fabricated. • Transmittance increased to 99.0%, significantly higher than that of commercial solar glasses. • The performance of standard solar cells with the AR coating was enhanced as much as 6.6%. - Abstract: High performance broadband antireflective (AR) and water-repellent coatings were fabricated on glass substrates by assembly of silica nanoparticles and polyelectrolytes via the layer-by-layer (LbL) assembly technique, followed by calcination and hydrophobic modification. A porous poly(diallyladimethylammonium chloride) (PDDA)/20 nm SiO2 nanoparticles (S-20) multilayer coating with AR property was prepared first. The maximum transmittance is as high as 99.0%, while that of the glass substrate is only 91.3%. After calcination and hydrophobic modification, the coating became water-repellent while maintaining the good AR property. Such water-repellent AR coatings can improve the short-circuit current of solar cells as much as 6.6% in comparison with glass substrates without the coatings. Scanning electron microscopy (SEM) was used to observe the morphology and thickness of coatings. Transmission spectra and reflection spectra were characterized by UV–vis spectrophotometer. The surface wettability was studied by a contact angle/interface system

  11. Breath Figure-Assisted Fabrication of Nanostructured Coating on Silicon Surface and Evaluation of Its Antireflection Power

    Directory of Open Access Journals (Sweden)

    Francesco Galeotti

    2016-01-01

    Full Text Available We report our recent results on the fabrication of nanostructured polymer layers aimed at developing efficient antireflection coating on silicon. The proposed manufacturing approach is based on self-assembly and relies on breath figure formation. By simple and straightforward operations, we are able to produce different nanostructured coatings: densely packed nanodomes, randomly distributed nanopores, and multilayered close-packed nanopores. By optical reflectivity measurements on coated silicon wafers, we show that the latter type of nanostructure is able to reduce the reflectivity of standard silicon surface (≈40% at 450 nm to about 10%.

  12. Broadband terahertz absorption enabled by coating an ultrathin antireflection film on doped semiconductor.

    Science.gov (United States)

    Wu, Hongxing; Shi, Fenghua; Chen, Yihang

    2016-09-01

    We show that perfect absorption of terahertz wave can be achieved in a compact system where an ultrathin film of lossless dielectric is coated on a doped semiconductor substrate. Due to the nontrivial reflection phase shift at the interface between the two media, strong resonant behavior and the concomitant antireflection occur at wavelengths that are much larger than the thickness of the dielectric film, resulting in strong absorption of the incident wave in a wide frequency range. Using this mechanism, we design a broadband terahertz absorber by coating a Ge film on a highly doped GaAs substrate. We show that such a system not only has a perfect absorption peak, but also exhibits high absorptance (over 0.9) within a fractional bandwidth of over 20%. By varying the free carrier density in the GaAs substrate, the central frequency of the absorption band can be tuned from 1.79 to 2.69 THz. In addition, the absorption performance of the proposed system is shown to be insensitive to both incident angle and polarization. Our results offer a low-cost way for the design of absorption-based THz devices. PMID:27607670

  13. Antireflective Coatings using Layer-by-Layer Self Assembly of Silica and Titania Nanoparticles

    Science.gov (United States)

    Velasco Castedo, Raisa; Lal, Anitesh Anand; Mazilu, Dan

    2011-03-01

    It is known that glass substrates (borosilicate glass) reflect about 4% of light at each air/glass interface and thus, they transmit only 92% of light. For some devices like camera lenses, it is important to maximize the amount of transmitted light. Previous research has demonstrated that it is possible to do so by adding antireflective coatings to the substrates. Our research aimed to deposit thin films on glass substrates that would minimize the reflectance of light and thus, maximize its transmittance. The thin films consisted of multiple alternating layers of silica and titania nanoparticles following the theory behind double-quarter periodic systems and were deposited on the substrates via the ISAM (ionically self-assembled monolayers) technique. Several experiments were conducted in order to investigate the factors that affected the quality of the coatings and some of the significant factors observed were the pH and the molarity of the silica, titania and PDDA solutions. A number of factor-level combinations yielded transmittances in excess of 96%, well above the value for uncoated substrates. R.E.Lee Summer Research Program at Washington and Lee University.

  14. Deep-ultraviolet tailored- and low-refractive index antireflection coatings for light-extraction enhancement of light emitting diodes

    Science.gov (United States)

    Yan, Xing; Shatalov, Max; Saxena, Tanuj; Shur, Michael S.

    2013-04-01

    An omnidirectional antireflection (AR) coating for a deep-ultraviolet (UV) AR band is designed and fabricated on the sapphire substrate of a deep-UV flip-chip light-emitting diode (LED) device. The two-layer AR coating uses the tailored- and low-refractive index nanoporous alumina fabricated by glancing-angle deposition methodology. The AR coating effectively matches the refractive indices between the air and sapphire substrate. At close-to-normal angles of incidence, this AR coating almost completely eliminates the Fresnel reflection at the sapphire/air interface of the deep-UV LED device. The resulting improvement of the light-extraction efficiency by 8% is in good agreement with the simulation results. For a total thickness of 172 nm for the two-layer AR coating, extinction was negligible (coating applications.

  15. Robust antireflection coatings By UV cross-linking of silica nanoparticles and diazo-resin polycation

    Science.gov (United States)

    Ridley, Jason I.; Heflin, James R.; Ritter, Alfred L.

    2007-09-01

    Antireflection coatings have been fabricated by self-assembly using silica nanoparticles. The ionic self-assembled multilayer (ISAM) films are tightly packed and homogeneous. While the geometric properties of a matrix of spherical particles with corresponding void interstices are highly suitable to meet the conditions for minimal reflectivity, it is also a cause for the lack of cohesion within the constituent body, as well as to the substrate surface. This study investigates methods for improving the interconnectivity of the nanoparticle structure. One such method involves UV curing of diazo-resin (DAR)/silica nanoparticle films, thereby converting the ionic interaction into a stronger covalent bond. Factorial analysis and response surface methods are incorporated to determine factors that affect film properties, and to optimize their optical and adhesive capabilities. The second study looks at the adhesive strength of composite multilayer films. Films are fabricated with silica nanoparticles and poly(allylamine hydrochloride) (PAH), and dipped into aqueous solutions of PAH and poly(methacrylic acid, sodium salt) (PMA) to improve cohesion of silica nanoparticles in the matrix, as well as binding strength to the substrate surface. The results of the two studies are discussed.

  16. Study of major factors to affect photoresist profile on developable bottom anti-reflective coating process

    Science.gov (United States)

    Roh, Hyo Jung; Ju, Dong Kyu; Kim, Hyun Jin; Kim, Jaehyun

    2011-04-01

    As critical dimensions continue to shrink in lithography, new materials will be needed to meet the new demands imposed by this shrinkage. Recently, there are needs for novel materials with various substrates and immersing process, including double patterning process, a high resolution implant process, and so on. Among such materials, Developable Bottom Anti-reflective Coating material (DBARC) is a good candidate for high resolution implant application as well as double patterning. DBARC should have reflectivity control function as an ordinary BARC, as well as an appropriate solubility in TMAH-based conventional developer after exposure and bake process. The most distinguished advantage of DBARC is to skip BARC etch process that is required in normal BARC process. In spite of this advantage, the photoresist profile on DBARC could be influenced by components and process conditions of DBARC. Several groups have tried to solve this issue to implement DBARC to new process. We have studied material-related factors affecting photoresist profiles, such as a polymer, photo-acid generators (PAGs), and additives. And we explored the effect of process condition for photoresist and DBARC. In case of polymer, we studied the effect of dissolution rate in developer and crosslinking functionality. For PAGs and additives, the effect of acid diffusivity and cross-linking degree according to their bulkiness were examined. We also evaluated coated film stability in a photoresist solvent after BARC bake process and compared lithographic performance of various DBARC formulations. In addition, the effect of photoresist profile with bake condition of photoresist and DBARC were investigated. In this paper, we will demonstrate the most influential factors of DBARC to photoresist profile and suggest the optimum formulation and process condition for DBARC application.

  17. Antireflective bilayer coatings based on Al2O3 film for UV region

    Directory of Open Access Journals (Sweden)

    Marszałek Konstanty

    2015-03-01

    Full Text Available Bilayer antireflective coatings consisting of aluminium oxide Al2O3/MgF2 and Al2O3/SiO2 are presented in this paper. Oxide films were deposited by means of e-gun evaporation in vacuum of 5 × 10-3 Pa in the presence of oxygen, and magnesium fluoride was prepared by thermal evaporation on heated optical lenses made from quartz glass (Corning HPFS. Substrate temperature was maintained at 250 _C during the deposition. Thickness and deposition rate were controlled with a thickness measuring system Inficon XTC/2. The experimental results of the optical measurements carried out during and after the deposition process have been presented. Physical thickness measurements were made during the deposition process and resulted in 44 nm/52 nm for Al2O3/MgF2 and 44 nm/50 nm for Al2O3/SiO2 system. Optimization was carried out for ultraviolet region with minimum of reflectance at 300 nm. The influence of post deposition annealing on the crystal structure was determined by X-ray measurements. In the range from ultraviolet to the beginning of visible region, the reflectance of both systems decreased and reached minimum at 290 nm. The value of reflectance at this point, for the coating Al2O3/MgF2 was equal to R290nm = 0.6 % and for Al2O3/SiO2R290nm = 1.1 %. Despite the difference between these values both are sufficient for applications in the UV optical systems for medicine and UV laser technology.

  18. Studies and testing of antireflective (AR) coatings for soda-lime glass

    Science.gov (United States)

    Pastirik, E. M.; Sparks, T. G.; Coleman, M. G.

    1978-01-01

    Processes for producing antireflection films on glass are concentrated in three areas: acid etching of glass, plasma etching of glass, and acid development of sodium silicate films on glass. The best transmission was achieved through the acid etching technique, while the most durable films were produced from development of sodium silicate films. Control of the acid etching technique is presently inadequate for production implementation. While films having excellent antireflective properties were fabricated by plasma etching techniques, all were water soluble.

  19. Reflective and antireflective coatings for the optical chain of the ASTRI SST-2M prototype

    Science.gov (United States)

    Bonnoli, Giacomo; Canestrari, Rodolfo; Catalano, Osvaldo; Pareschi, Giovanni; Perri, Luca; Stringhetti, Luca

    2013-09-01

    ASTRI is a Flagship Project of the Italian Ministry of Education, University and Research, led by the Italian National Institute of Astrophysics, INAF. One of the main aims of the ASTRI Project is the design, construction and on-field verification of a dual mirror (2M) end-to-end prototype for the Small Size Telescope (SST) envisaged to become part of the Cherenkov Telescope Array. The ASTRI SST-2M prototype is designed according to the Schwarzschild-Couder optical scheme, and adopts a camera based on Silicon Photo Multipliers (SiPM); it will be assembled at the INAF astronomical site of Serra La Nave on mount Etna (Catania, Italy) in the second half of 2014, and will start scientific validation phase soon after. With its 4m wide primary dish, the telescope will be sensitive to multi-TeV Very High Energy (VHE) gamma rays up to 100 TeV and above, with a point spread function of ~2 arcminutes and a wide (semiaperture 4.8°) corrected field of view. The peculiarities of the optical design and of the SiPM bandpass pushed towards specifically optimized choices in terms of reflective coatings for both the primary and the secondary mirror. Fully dielectric multi-layer coatings have been developed and tested as an option for the primary mirror, aiming to filter out the large Night Sky Background contamination at wavelengths λ>~700 nm. On the other hand, for the large monolithic secondary mirror a simpler design with quartz-overcoated aluminium has been optimized for incidences far from normality. The conformation of the ASTRI camera in turn pushed towards the design of a reimaging system based on thin pyramidal light guides, that could be optionally integrated in the focal surface, aiming to increase the fill factor. An anti-reflective coating optimized for a wide range of incident angles faraway from normality was specifically developed to enhance the UV-optical transparency of these elements. The issues, strategy, simulations and experimental results are thoroughly

  20. A simplified method for generating periodic nanostructures by interference lithography without the use of an anti-reflection coating

    International Nuclear Information System (INIS)

    Interference lithography has proven to be a useful technique for generating periodic sub-diffraction limited nanostructures. Interference lithography can be implemented by exposing a photoresist polymer to laser light using a two-beam arrangement or more simply a one beam configuration based on a Lloyd's Mirror Interferometer. For typical photoresist layers, an anti-reflection coating must be deposited on the substrate to prevent adverse reflections from cancelling the holographic pattern of the interfering beams. For silicon substrates, such coatings are typically multilayered and complex in composition. By thinning the photoresist layer to a thickness well below the quarter wavelength of the exposing beam, we demonstrate that interference gratings can be generated without an anti-reflection coating on the substrate. We used ammonium dichromate doped polyvinyl alcohol as the positive photoresist because it provides excellent pinhole free layers down to thicknesses of 40 nm, and can be cross-linked by a low-cost single mode 457 nm laser, and can be etched in water. Gratings with a period of 320 nm and depth of 4 nm were realized, as well as a variety of morphologies depending on the photoresist thickness. This simplified interference lithography technique promises to be useful for generating periodic nanostructures with high fidelity and minimal substrate treatments

  1. A simplified method for generating periodic nanostructures by interference lithography without the use of an anti-reflection coating

    Energy Technology Data Exchange (ETDEWEB)

    Kapon, Omree; Muallem, Merav; Palatnik, Alex; Aviv, Hagit; Tischler, Yaakov R. [Department of Chemistry, Bar-Ilan University, Ramat-Gan 5920002 (Israel); Bar-Ilan University Institute for Nanotechnology and Advanced Materials, Ramat-Gan 5920002 (Israel)

    2015-11-16

    Interference lithography has proven to be a useful technique for generating periodic sub-diffraction limited nanostructures. Interference lithography can be implemented by exposing a photoresist polymer to laser light using a two-beam arrangement or more simply a one beam configuration based on a Lloyd's Mirror Interferometer. For typical photoresist layers, an anti-reflection coating must be deposited on the substrate to prevent adverse reflections from cancelling the holographic pattern of the interfering beams. For silicon substrates, such coatings are typically multilayered and complex in composition. By thinning the photoresist layer to a thickness well below the quarter wavelength of the exposing beam, we demonstrate that interference gratings can be generated without an anti-reflection coating on the substrate. We used ammonium dichromate doped polyvinyl alcohol as the positive photoresist because it provides excellent pinhole free layers down to thicknesses of 40 nm, and can be cross-linked by a low-cost single mode 457 nm laser, and can be etched in water. Gratings with a period of 320 nm and depth of 4 nm were realized, as well as a variety of morphologies depending on the photoresist thickness. This simplified interference lithography technique promises to be useful for generating periodic nanostructures with high fidelity and minimal substrate treatments.

  2. A simplified method for generating periodic nanostructures by interference lithography without the use of an anti-reflection coating

    Science.gov (United States)

    Kapon, Omree; Muallem, Merav; Palatnik, Alex; Aviv, Hagit; Tischler, Yaakov. R.

    2015-11-01

    Interference lithography has proven to be a useful technique for generating periodic sub-diffraction limited nanostructures. Interference lithography can be implemented by exposing a photoresist polymer to laser light using a two-beam arrangement or more simply a one beam configuration based on a Lloyd's Mirror Interferometer. For typical photoresist layers, an anti-reflection coating must be deposited on the substrate to prevent adverse reflections from cancelling the holographic pattern of the interfering beams. For silicon substrates, such coatings are typically multilayered and complex in composition. By thinning the photoresist layer to a thickness well below the quarter wavelength of the exposing beam, we demonstrate that interference gratings can be generated without an anti-reflection coating on the substrate. We used ammonium dichromate doped polyvinyl alcohol as the positive photoresist because it provides excellent pinhole free layers down to thicknesses of 40 nm, and can be cross-linked by a low-cost single mode 457 nm laser, and can be etched in water. Gratings with a period of 320 nm and depth of 4 nm were realized, as well as a variety of morphologies depending on the photoresist thickness. This simplified interference lithography technique promises to be useful for generating periodic nanostructures with high fidelity and minimal substrate treatments.

  3. Wide band antireflective coatings Al2O3 / HfO2 / MgF2 for UV region

    Science.gov (United States)

    Winkowski, P.; Marszałek, Konstanty W.

    2013-07-01

    Deposition technology of the three layers antireflective coatings consists of hafnium compound are presented in this paper. Oxide films were deposited by means of e-gun evaporation in vacuum of 5x10-5 mbar in presence of oxygen and fluoride films by thermal evaporation. Substrate temperature was 250°C. Coatings were deposited onto optical lenses made from quartz glass (Corning HPFS). Thickness and deposition rate were controlled by thickness measuring system Inficon XTC/2. Simulations leading to optimization of thickness and experimental results of optical measurements carried during and after deposition process were presented. Physical thickness measurements were made during deposition process and were equal to 43 nm/74 nm/51 nm for Al2O3 / HfO2 / MgF2 respectively. Optimization was carried out for ultraviolet region from 230nm to the beginning of visible region 400 nm. In this region the average reflectance of the antireflective coating was less than 0.5% in the whole range of application.

  4. Injection moulding antireflective nanostructures

    DEFF Research Database (Denmark)

    Christiansen, Alexander Bruun; Clausen, Jeppe Sandvik; Mortensen, N. Asger;

    We present a method for injection moulding antireflective nanostructures on large areas, for high volume production. Nanostructured black silicon masters were fabricated by mask-less reactive ion etching, and electroplated with nickel. The nickel shim was antistiction coated and used in an...... index of the nanostructured surfaces was estimated from atomic force micrographs and the theoretical reflectance was calculated using the transfer matrix method and effective medium theory. The measured reflectance shows good agreement with the theory of graded index antireflective nanostructures...

  5. Synthesis of antireflective silica coatings through the synergy of polypeptide layer-by-layer assemblies and biomineralization

    Science.gov (United States)

    Lee, Yung-Lun; Lin, Ting-Xuan; Hsu, Feng-Ming; Jan, Jeng-Shiung

    2016-01-01

    We report a versatile approach to synthesize silica coatings with antireflective (AR) characteristics through the combination of a layer-by-layer (LbL) assembly technique and biomineralization. LbL assembled decanoyl-modified poly(l-lysine)/poly(l-glutamic acid) (PLL-g-Dec/PLGA) multilayer films were used as templates for silica mineralization, followed by calcination. The specific deposition of silica onto the LbL polypeptide assemblies through amine-catalyzed polycondensation resulted in silica coatings that exhibited the transcription of the nano-/microstructured polypeptide films and their film thickness and porosity can be tuned by varying the number of bilayers, degree of substitution, and PLL molecular weight. AR silica coatings exhibiting more than 6% increase in transmittance in the near UV/visible spectral range can be obtained at an optimized refractive index, thickness, and surface roughness. The abrasion test showed that the silica coatings exhibited sufficient structural durability due to continuous silica nanostructures and low surface roughness. This study demonstrated that nanostructured thin films can be synthesized for AR coatings using the synergy between the LbL assembly technique and biomineralization.We report a versatile approach to synthesize silica coatings with antireflective (AR) characteristics through the combination of a layer-by-layer (LbL) assembly technique and biomineralization. LbL assembled decanoyl-modified poly(l-lysine)/poly(l-glutamic acid) (PLL-g-Dec/PLGA) multilayer films were used as templates for silica mineralization, followed by calcination. The specific deposition of silica onto the LbL polypeptide assemblies through amine-catalyzed polycondensation resulted in silica coatings that exhibited the transcription of the nano-/microstructured polypeptide films and their film thickness and porosity can be tuned by varying the number of bilayers, degree of substitution, and PLL molecular weight. AR silica coatings exhibiting

  6. Antireflection coatings for Si-base photoelectrical devices made of lanthanum, samarium and dysprosium fluorides

    International Nuclear Information System (INIS)

    Spectral dependences of light transmission through rare-element fluorides and the antireflection effect of the surface of silicon photoelectric converters with usage of the fluorides are investigated. It is established that fluoride films of lanthanum, samarium and dysprosium have a high transparency in the spectral reflection coefficient for a silicon surface up to 3.3-4.0%

  7. Employing SiO_2 Buffer Layer to Improve Adhesion of the Frequency-doubled Antireflection Coating on LBO

    Institute of Scientific and Technical Information of China (English)

    TAN Tianya; SHAN Jing; WU Wei; GUO Yongxin; SHAO Jianda; FAN Zhengxiu

    2009-01-01

    Frequency-doubled antireflection coatings simultaneously effective at 1064 nm and 532 nm were deposited on the lithium triborate(LiB_3O_5 or LBO)crystals using the electron beam evaporation method.Comparing with the sample without buffer layer,it is found that the adhesion of the sample with buffer layer of SiO_2 between coating and LBO substrate is improved significantly from 137.4 mN to greater than 200 mN.And the laser-induced damage threshold is increased by 20% from 15.1 J/cm~2 to 18.6 J/cm~2 .The strengthening mechanism of adhesion of the buffer layer of SiO_2 is discussed by considering full plastic indentation and shear theory.

  8. Two-layer anti-reflection coating with mullite and polyimide foam for large-diameter cryogenic infrared filters

    CERN Document Server

    Inoue, Yuki; Hasegawa, Masaya; Hazumi, Masashi; Hori, Yasuto; Suzuki, Aritoki; Tomaru, Takayuki; Matsumura, Tomotake; Sakata, Toshifumi; Minamoto, Tomoyuki; Hirai, Tohru

    2016-01-01

    We have developed a novel two-layer anti-reflection (AR) coating method for large-diameter infrared (IR) filters made of alumina, for the use at cryogenic temperatures in millimeter wave measurements. Thermally- sprayed mullite and polyimide foam (Skybond Foam) are used as the AR material. An advantage of the Skybond Foam is that the index of refraction is chosen between 1.1 and 1.7 by changing the filling factor. Combination with mullite is suitable for wide-band millimeter wave measurements with sufficient IR cutoff capability. We present the material properties, fabrication of a large-diameter IR filter made of alumina with this AR coating method, and characterizations at cryogenic temperatures. This technology can be applied to a low-temperature receiver system with a large-diameter focal plane for next-generation cosmic microwave background (CMB) polarization measurements, such as POLARBEAR-2 (PB-2).

  9. Almost zero reflectance of a silicon oxynitride/porous silicon double layer antireflection coating for silicon photovoltaic cells

    Energy Technology Data Exchange (ETDEWEB)

    Aroutiounian, V M [Department of Semiconductor Physics and Microelectronics, Yerevan State University, 1 Alex Manoukian Street, Yerevan 375025 (Armenia); Martirosyan, Kh [Department of Semiconductor Physics and Microelectronics, Yerevan State University, 1 Alex Manoukian Street, Yerevan 375025 (Armenia); Soukiassian, P [Commissariat a l' Energie Atomique, Laboratoire SIMA associe a l' Universite de Paris-Sud/Orsay, DSM/DRECAM/SPCSI, Batiment 462, Saclay, 91191 Gif-sur-Yvette Cedex (France)

    2006-04-21

    Reflectance spectrum calculations for a silicon oxynitride (SiO{sub x}N{sub y})-porous silicon (PS) double layer antireflection coating is performed using the matrix method. The results are compared with the corresponding spectrum of diamond-like carbon (DLC)/PS and SiO{sub 2}/TiO{sub 2} double layer coatings. A lower reflectance in the visible and infrared regions of the solar spectrum for the SiO{sub x}N{sub y}/PS double layer is obtained, especially in the 450-600 nm spectral range (with a flat reflectance response remaining as low as {approx}0.01%), which corresponds to the maximum intensity of solar irradiation. These findings are of importance in solar cell applications.

  10. Functional photocatalytically active and scratch resistant antireflective coating based on TiO2 and SiO2

    Science.gov (United States)

    Mazur, M.; Wojcieszak, D.; Kaczmarek, D.; Domaradzki, J.; Song, S.; Gibson, D.; Placido, F.; Mazur, P.; Kalisz, M.; Poniedzialek, A.

    2016-09-01

    Antireflection (AR) multilayer coating, based on combination of five TiO2 and SiO2 thin films, was deposited by microwave assisted reactive magnetron sputtering process on microscope glass substrates. In this work X-ray diffraction, X-ray photoelectron spectroscopy, atomic force microscopy and wettability measurements were used to characterize the structural and surface properties of the deposited coating. These studies revealed that prepared coating was amorphous with low surface roughness. Photocatalytic properties were determined based on phenol decomposition reaction. Measurements of optical properties showed that transmittance in the visible wavelength range was increased after the deposition of AR coating as-compared to bare glass substrate. The mechanical properties were determined on the basis of nano-indentation and scratch resistance tests. Performed research has shown that deposition of an additional thin 10 nm thick TiO2 thin film top layer, the prepared AR coating was photocatalytically active, hydrophobic, scratch resistant and had increased hardness as-compared to bare glass substrate. These results indicate that prepared AR multilayer could be used also as a self-cleaning and protective coating.

  11. Antireflection and self-cleaning properties of a moth-eye-like surface coated with TiO2 particles.

    Science.gov (United States)

    Nakata, Kazuya; Sakai, Munetoshi; Ochiai, Tsuyoshi; Murakami, Taketoshi; Takagi, Katsuhiko; Fujishima, Akira

    2011-04-01

    Poly(ethylene terephthalate) (PET) films with a moth-eye-like surface are coated with TiO(2) particles to form self-cleaning antireflective films. The use of a TiO(2) suspension of high concentration to coat the PET surface produces a thicker TiO(2) layer with smaller pores, whereas a low concentration of a TiO(2) suspension gives a thinner layer of TiO(2) with larger pores. The PET films coated with TiO(2) particles exhibit a high transmittance of 76-95% and almost no absorption in the range of 400-800 nm. The PET films coated with a TiO(2) suspension with a concentration of ≥2 vol % exhibit superhydrophilicity after irradiation with UV light. After irradiation, the superhydrophilic nature is retained for at least 18 days. The TiO(2)-coated PET films showed the ability to decompose methylene blue under UV irradiation. PMID:21391643

  12. Antireflection coating formed by plasma-enhanced chemical-vapor deposition for terahertz-frequency germanium optics

    Science.gov (United States)

    Hosako, Iwao

    2003-07-01

    A method of manufacturing optical coatings for germanium optics used at terahertz frequencies has been developed. The various optical coatings used at terahertz frequencies are difficult to manufacture conventionally because these coatings must be as thick as several tens of micrometers, which is far thicker than those used in the optical region. One way to overcome this problem is to form a silicon oxide layer through plasma-enhanced chemical-vapor deposition, with silane (SiH4) as a source gas. Using this method, I formed 21-μm-thick silicon oxide films as antireflection (AR) layers for germanium optics and obtained low reflection at 1.7 THz (wavelength, λ = 175 μm). This method is easily applied to large-aperture optics and micro-optics as well as to optics with a complex surface form. The AR coatings can also be formed for photoconductive detectors made from germanium doped with gallium at a low temperature (160 °C) this low temperature ensures that the doped impurities in the germanium do not diffuse. Fabrication of optical coatings upon substrates that have refractive indices of 3.84-11.7 may also be possible by control of the refractive indices of the deposited layers.

  13. 17.1%-Efficient Multi-Scale-Textured Black Silicon Solar Cells without Dielectric Antireflection Coating: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Toor, F.; Page, M. R.; Branz, H. M.; Yuan, H. C.

    2011-07-01

    In this work we present 17.1%-efficient p-type single crystal Si solar cells with a multi-scale-textured surface and no dielectric antireflection coating. Multi-scale texturing is achieved by a gold-nanoparticle-assisted nanoporous etch after conventional micron scale KOH-based pyramid texturing (pyramid black etching). By incorporating geometric enhancement of antireflection, this multi-scale texturing reduces the nanoporosity depth required to make silicon 'black' compared to nanoporous planar surfaces. As a result, it improves short-wavelength spectral response (blue response), previously one of the major limiting factors in 'black-Si' solar cells. With multi-scale texturing, the spectrum-weighted average reflectance from 350- to 1000-nm wavelength is below 2% with a 100-nm deep nanoporous layer. In comparison, roughly 250-nm deep nanopores are needed to achieve similar reflectance on planar surface. Here, we characterize surface morphology, reflectivity and solar cell performance of the multi-scale textured solar cells.

  14. ZnSe hollow nanospheres in mechanically stable near-IR antireflection coatings for ZnSe substrates

    Science.gov (United States)

    Li, Chao; Luo, Rui-Chun; Mao, Yong-Qiang; Du, Xi-Wen; Yang, Jing

    2016-09-01

    Though possessing low absorption throughout a wide infrared (IR) spectral regime, owing to a high refractive index, zinc selenide substrates are generally covered by antireflection coatings (ARCs) for practical optical uses. However, achieving a high transmission of ZnSe substrates in the near-IR (NIR) region is still challenging. Herein, for the first time, colloidal ZnSe hollow nanospheres (HNSs) smaller than 100 nm were prepared and adopted to assemble ARCs for ZnSe substrates. The voiding kinetics of the HNSs was found to agree well with the nanoscale Kirkendall effect, and the self-diffusion of the Zn ion in the core was faster than its diffusion through the ZnSe shell. With single-index ARCs, the transmission of ZnSe substrates was remarkably enhanced in the NIR region, with up to an 18% increase at 840 nm. Besides, the ZnSe HNS-based ARCs showed superior mechanical stability even under violent ultrasonication in organic solutions. We expect that ZnSe HNSs will make it possible to construct graded-index ARCs to realize omnidirectional and broadband antireflection in IR, through further tuning of HNSs’ void fraction.

  15. Broadband omnidirectional antireflection coatings for metal-backed solar cells optimized using simulated annealing algorithm incorporated with solar spectrum.

    Science.gov (United States)

    Chang, Yin-Jung; Chen, Yu-Ting

    2011-07-01

    Broadband omnidirectional antireflection (AR) coatings for solar cells optimized using simulated annealing (SA) algorithm incorporated with the solar (irradiance) spectrum at Earth's surface (AM1.57 radiation) are described. Material dispersions and reflections from the planar backside metal are considered in the rigorous electromagnetic calculations. Optimized AR coatings for bulk crystalline Si and thin-film CuIn(1-x)GaxSe(2) (CIGS) solar cells as two representative cases are presented and the effect of solar spectrum in the AR coating designs is investigated. In general, the angle-averaged reflectance of a solar-spectrum-incorporated AR design is shown to be smaller and more uniform in the spectral range with relatively stronger solar irradiance. By incorporating the transparent conductive and buffer layers as part of the AR coating in CIGS solar cells (2μm-thick CIGS layer), a single MgF(2) layer could provide an average reflectance of 8.46% for wavelengths ranging from 350 nm to 1200 nm and incident angles from 0° to 80°. PMID:21747557

  16. Influence of Vacuum Organic Contaminations on Laser-Induced Damage of 1064 nm Anti-Reflective Coatings

    Institute of Scientific and Technical Information of China (English)

    CUI Yun; LIU Shi-Jie; HE Hong-Bo; ZHAO Yuan-An; SHAO Jian-Da; FAN Zheng-Xiu

    2007-01-01

    We investigate the influence of vacuum organic contaminations on laser-induced damage threshold (LIDT) of optical coatings. Anti-reflective (AR) coatings at 1064nm made by Ta2O5/SiO2 are deposited by the ion beam sputtering method. The LIDTs of AR coatings are measured in vacuum and in atmosphere, respectively. It is exhibited that contaminations in vacuum are easily to be absorbed onto optical surface because of lower pressure,and they become origins of damage, resulting in the decrease of LIDT from 24.5 J/cm2 in air to 15.7J/cm2 in vacuum. The LIDT of coatings in vacuum has is slightly changed compared with the value in atmosphere after the organic contaminations are wiped off. These results indicate that organic contaminations are the main reason of the LIDT decrease in vacuum. Additionally, damage morphologies have distinct changes from vacuum to atmosphere because of the differences between the residual stress and thermal decomposability of filmy materials.

  17. Long term testing and evaluation of PV modules with and without Sunarc antireflective coating of the cover glass

    DEFF Research Database (Denmark)

    Perers, Bengt; Furbo, Simon; Han, Jiangong; Kong, Weiqiang; Stergiakis, Stamoulis

    2015-01-01

    3% up to 6%. The improvement is best in facade and off south tilted orientations, where the better incidence angle modifier, has a larger influence. In the PV application only one side of the glass treatment is active. This reduces the possible improvement compared to solar thermal and greenhouse...... applications. In PV applications the slightly higher cell temperature, due to the higher transmittance of the glass for all solar wavelengths, reduces the potential electrical performance improvement.......Two Photovoltaic (PV) modules have been manufactured by Swemodule. One with Sunarc antireflective coated glass and one without glass surface treatment. The modules have been tested at DTU during 16 months under realistic outdoor conditions. Exactly the same polycrystalline cells were used in the...

  18. Dual wavelength laser-induced damage threshold measurements of alumina/silica and hafnia/silica ultraviolet antireflective coatings.

    Science.gov (United States)

    Mrohs, Marius; Jensen, Lars; Günster, Stefan; Alig, Thimotheus; Ristau, Detlev

    2016-01-01

    An approach for the measurement of the laser-induced damage threshold with two wavelengths combined was made while testing antireflective coatings for the wavelengths 266 and 532 nm. Samples were made of Al2O3/SiO2 and HfO2/SiO2 ion beam sputtered films. The results show that adding radiation of a second wavelength might lead to a significant reduction of the threshold. The damage morphology of single and dual wavelength tests is very similar and does not suggest an altered damage mechanism. Further investigations indicated that the dual wavelength threshold is a function of the temporal delay of the two pulses. PMID:26835628

  19. Preparation and stress evolution of sol–gel SiO2 antireflective coatings for small-size anisotropic lithium triborate crystals

    OpenAIRE

    Bingtao Tian; Xiaodong Wang; Yanyan Niu; Jinlong Zhang; Qinghua Zhang; Zhihua Zhang; Guangming Wu; Bin Zhou; Jun Shen

    2016-01-01

    Lithium triborate (LiB3O5, LBO) crystal is now one of the most useful nonlinear optical materials for frequency conversion of high power lasers. The use of the crystal, however, has been hampered by the unavailability of antireflective (AR) coatings with high laser damage resistance. In this work, a “point contact” dip-coating method is developed to prepare sol–gel SiO2 AR coatings on small-size LBO crystals. Using this approach, we obtain a homogenous coating surface on an 8 mm×8 mm×3 mm LBO...

  20. An abrasion-resistant and broadband antireflective silica coating by block copolymer assisted sol-gel method.

    Science.gov (United States)

    Zou, Liping; Li, Xiaoguang; Zhang, Qinghua; Shen, Jun

    2014-09-01

    A double-layer broadband antireflective (AR) coating was prepared on glass substrate via sol-gel process using two kinds of acid-catalyzed TEOS-derived silica sols. The relative dense layer with a porosity of ∼10% was obtained from an as-prepared sol, while the porous layer with a porosity of ∼55% was from a modified one with block copolymer (BCP) Pluronic F127 as template which results in abundant ordered mesopores. The two layers give rise to a reasonable refractive index gradient from air to the substrate and thus high transmittance in a wide wavelength range, and both of them have the same tough skeleton despite different porosity, for which each single-layer and the double-layer coatings all behaved well in the mechanical property tests. The high transmittance and the strong ability of resisting abrasion make this coating promising for applications in some harsh conditions. In addition, the preparation is simple, low-cost, time-saving, and flexible for realizing the optical property. PMID:25117300

  1. Improvement in power conversion efficiency of organic photovoltaic devices by using excimer ultraviolet-radiation induced mesoporous silica anti-reflection coating

    International Nuclear Information System (INIS)

    An anti-reflection thin film with a mesoporous structure is demonstrated to improve the light-collection and photocurrent-generation abilities of organic photovoltaic cells. The mesoporous film was prepared by sol–gel-derived silica with an excimer ultraviolet-radiation removable self-assembling triblock copolymer as the nanostructured template. The method for fabricating this film was much easier than conventional processes used to prepare anti-reflection materials as they involve vacuum or high-temperature conditions. By using this mesoporous film as an anti-reflection coating on the glass side of an indium tin oxide-coated glass substrate, an enhancement of about 6% in the photocurrent generation could be achieved in a device with a poly(3-hexylthiophene):(6,6)-phenyl-C61-butyric acid methyl ester bulk-heterojunction layer. A glass substrate with a coating of the mesoporous anti-reflection film showed an obvious improvement in transmittance for wavelengths extending from the visible-light region to the near-infrared region. The result also indicates that the prepared anti-reflection material is not only compatible with the photoactive materials with wide band gaps but works very well with semiconductors with small band gaps as well, e.g. thieno(3,4-b)-thiophene/benzodithiophene copolymer (PTB7). In this work, ∼ 3.6% photocurrent enhancement can also be obtained in PTB7-based solar cells, indicating the wide compatibility of thus-prepared mesoporous film. - Highlights: • A mesoporous film is demonstrated to improve light collection of organic photovoltaic cells. • The film was prepared by sol–gel silica with a light removable copolymer template. • An enhancement of 6% in photocurrent could be achieved in the devices

  2. TiO2/Ni composite as antireflection coating for solar cell application

    Science.gov (United States)

    Haider, Adawiya J.; Najim, Aus A.; Muhi, Malik A. H.

    2016-07-01

    Titanium dioxide (TiO2) considered as one of the best material already used as a window in solar cells due to its antireflection capability. In this work, pure and Ni-doped (1, 3 and 5 wt%) TiO2 thin films were deposited using pulsed laser deposition (PLD) method. The optical measurements obtained by UV-vis indicate that the highest optical band gap was found with (5%) doping level (Eg=3.82 eV), corresponding to a lower reflectance and higher transmittance. Empirical equations between energy band gap and concentration level, reflectance with energy band gap, refractive index and concentration have been determined; a perfect fit with the experimental data was obtained.

  3. High efficiency antireflection coating in MWIR region (3.6-4.9 μm) simultaneously effective for Germanium and Silicon optics

    Science.gov (United States)

    Bhatt, Meenakshi; Nautiyal, B. B.; Bandyopadhyay, P. K.

    2010-01-01

    Antireflection coatings have critical importance in thermal imaging system working in MWIR region (3-5 μm) since optics of high refractive index materials are used. Germanium (Ge) and Silicon (Si) optics are used extensively in the MWIR thermal systems. In this paper a study has been carried out on the design and fabrication of multi-substrate antireflection coating effective for Germanium and Silicon optics in MWIR (3.6-4.9 μm) region. The wave band 3.6-4.9 μm is chosen for the reported work because detector system used in MWIR region has a band selection filter effective in the same wavelength region and atmospheric transmission window in MWIR region is effective in 3-5 μm spectral band. Comprehensive search method was used to design the multilayer stack on the substrate. The coating materials used in the design were Germanium (Ge), Hafnium oxide (HfO 2) and Y-Ba-Fluoride (IR-F625). The fabrication of coating was made in a coating plant fitted with Cryo pump system and residual gas analyzer (RGA). The evaporation was carried out at high vacuum (2-6 × 10 -6 mbar) with the help of electron beam gun system and layer thicknesses were measured with crystal monitor. The result achieved for the antireflection coating was 98.5% average transmission in 3.6-4.9 μm band for Germanium and Silicon optics. This work will be helpful in reducing the plant operation time, material and power consumption, as two different kinds of optics are simultaneously coated in a single coating cycle.

  4. Injection moulding antireflective nanostructures

    DEFF Research Database (Denmark)

    Christiansen, Alexander Bruun; Clausen, Jeppe Sandvik; Mortensen, N. Asger;

    2014-01-01

    We present a method for injection moulding antireflective nanostructures on large areas, for high volume production. Nanostructured black silicon masters were fabricated by mask-less reactive ion etching, and electroplated with nickel. The nickel shim was antistiction coated and used in an...... injection moulding process, to fabricate the antireflective surfaces. The cycle-time was 35 s. The injection moulded structures had a height of 125 nm, and the visible spectrum reflectance of injection moulded black polypropylene surfaces was reduced from 4.5±0.5% to 2.5±0.5%. The gradient of the refractive...

  5. Injection moulding antireflective nanostructures

    DEFF Research Database (Denmark)

    Christiansen, Alexander Bruun; Clausen, Jeppe Sandvik; Mortensen, N. Asger;

    We present a method for injection moulding antireflective nanostructures on large areas, for high volume production. Nanostructured black silicon masters were fabricated by mask-less reactive ion etching, and electroplated with nickel. The nickel shim was antistiction coated and used in an...... injection moulding process, to fabricate the antireflective surfaces. The cycle-time was 35 s. The injection moulded structures had a height of 125 nm, and the visible spectrum reflectance of injection moulded black polypropylene surfaces was reduced from 4.5±0.5% to 2.5±0.5%. The gradient of the refractive...

  6. Ion-plasma way of receiving strengthening heat reflecting anti-reflection coating

    International Nuclear Information System (INIS)

    The ion-plasma deposition strengthening heat reflecting clarifying coatings is developed for plastic screens of means of individual protection. The method of magnetron sputtering are received strengthening coatings with integrated coefficient of a transmission in visible area of a range more than 96%

  7. Realization of Colored Multicrystalline Silicon Solar Cells with SiO2/SiNx:H Double Layer Antireflection Coatings

    Directory of Open Access Journals (Sweden)

    Minghua Li

    2013-01-01

    Full Text Available We presented a method to use SiO2/SiNx:H double layer antireflection coatings (DARC on acid textures to fabricate colored multicrystalline silicon (mc-Si solar cells. Firstly, we modeled the perceived colors and short-circuit current density (Jsc as a function of SiNx:H thickness for single layer SiNx:H, and as a function of SiO2 thickness for the case of SiO2/SiNx:H (DARC with fixed SiNx:H (refractive index n=2.1 at 633 nm, and thickness = 80 nm. The simulation results show that it is possible to achieve various colors by adjusting the thickness of SiO2 to avoid significant optical losses. Therefore, we carried out the experiments by using electron beam (e-beam evaporation to deposit a layer of SiO2 over the standard SiNx:H for 156×156 mm2 mc-Si solar cells which were fabricated by a conventional process. Semisphere reflectivity over 300 nm to 1100 nm and I-V measurements were performed for grey yellow, purple, deep blue, and green cells. The efficiency of colored SiO2/SiNx:H DARC cells is comparable to that of standard SiNx:H light blue cells, which shows the potential of colored cells in industrial applications.

  8. Magnetron sputtered TiO/sub 2/ and Al/sub 2/O/sub 3/ antireflection coatings

    International Nuclear Information System (INIS)

    The optical and structural properties of single- and double-layer films from TiO/sub 2/ and Al/sub 2/O/sub 3/, obtained by the method of reactive magnetron sputtering at direct current are investigated with values of a discharge current density 5, 10 and 20 mA/cm/sup 2/ and partial oxygen presence P=8.7*10/sup -2/ Pa. The films were deposited on the silicon and quartz substrates using pipeline type magnetron apparatus with three magnetrons. The Ti- and Al - targets were installed on the magnetron's cathodes. The results of X-ray diffraction (RXD) evidence that the TiO/sub 2/ films have structure of anatase modification and Al/sub 2/O/sub 3/ films were amorphous. With the growth of the discharge current density the films with higher values of refraction coefficient were deposited. Computer simulation showed that the utilisation of the obtained TiO/sub 2/ and Al/sub 2/O/sub 3/ films one can be make double-layer antireflection coating. (AC) with an average value of the reflection coefficient not exceeding 3% within the spectral range of 0.4 - 1.1 mu m. (author)

  9. Rapid replication and facile modulation of subwavelength antireflective polymer film using injection nanomolding and optical property of multilayer coatings

    Science.gov (United States)

    Fuh, Yiin-Kuen; Peng, Cheng-Chang; Huang, Chieh-Tse

    2013-10-01

    A rapid, cost-effective and high-throughput process for nanotexturing subwavelength structures with high uniformity using the polycarbonate (PC) is realized via injection nanomolding. The process enables the precise control of nanohole array (NHA) surface topography (nanohole depth, diameter, and periodicity) over large areas thereby presenting a highly versatile platform for fabricating substrates with user-defined, functional performance. Specifically, the optical property of the PC substrates were systematically characterized and tuned through the modulation of the depths of NHA. The aspect ratio submicron holes can be easily modulated and experimentally proven by simply adjusting the molding temperature. The nanotextured depths were reliably fabricated in the range of 200 to 400 nm with a period of approximately 700 nm. The fabricated PC films can reduce the reflectivity from an original bare film of 10.2% and 8.9% to 1.4% and 2.1% with 400-nm depth of nanoholes at the wavelength of 400 and 550 nm, respectively. Compared with conventional moth-like nanostructures with nanopillar arrays with heights adjustable only by an etching process, this paper proposes a facile route with submicron holes to achieve a similar antireflective function, with a significantly reduced time and facile height modulation capability. Furthermore, the effects of multilayer coatings of dielectric and metallic layers on the nanomolded NHA have been performed and potential sensing application is explored.

  10. Nanocrystalline ZnO film deposited by ultrasonic spray on textured silicon substrate as an anti-reflection coating layer

    International Nuclear Information System (INIS)

    A ZnO thin film was successfully synthesized on glass, flat surface and textured silicon substrates by chemical spray deposition. The textured silicon substrate was carried out using two solutions (NaOH/IPA and Na2CO3). Textured with Na2CO3 solution, the sample surface exhibits uniform pyramids with an average height of 5 μm. The properties and morphology of ZnO films were investigated. X-ray diffraction (XRD) spectra revealed a preferred orientation of the ZnO nanocrystalline film along the c-axis where the low value of the tensile strain 0.26% was obtained. SEM images show that all films display a granular, polycrystalline morphology. The morphology of the ZnO layers depends dramatically on the substrate used and follows the contours of the pyramids on the substrate surface. The average reflectance of the textured surface was found to be around 13% and it decreases dramatically to 2.57% after deposition of a ZnO antireflection coating. FT-IR peaks arising from the bonding between Zn-O are clearly represented using a silicon textured surface. A very intense photoluminescence (PL) emission peak is observed for ZnO/textured Si, revealing the good quality of the layer. The PL peak at 380.5 nm (UV emission) and the high-intensity PL peak at 427.5 nm are observed and a high luminescence occurs when using a textured Si substrate.

  11. Nano-Enabled Low-Cost High-Performance UV Anti-Reflection Coatings Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Agiltron together with Prof. Michael Rubner's group at MIT is developing a new family of nanoporous, low refractive index coatings for next generation NASA UV...

  12. Broad Bandwidth Meta-Material Antireflection Coatings for Measurement of the Cosmic Microwave Background Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The effort's objective is to realize broadband low-reflectance coatings. The two key technical challenges are the design of the precision engineered materials...

  13. High-Quality Hollow Closed-Pore Silica Antireflection Coatings Based on Styrene-Acrylate Emulsion @ Organic-Inorganic Silica Precursor.

    Science.gov (United States)

    Guo, Zhaolong; Zhao, Haixin; Zhao, Wei; Wang, Tao; Kong, Depeng; Chen, Taojing; Zhang, Xiaoyan

    2016-05-11

    Making use of a facile and low-cost way for the preparation of a hierarchically organized novel hollow closed-pore silica antireflective coating (CHAR) with tailored optical properties and a mechanical reliability is of great interest in the field of solar photovoltaic technology. The process mainly contains two aspects: (1) a styrene-acrylate emulsion @ organic-inorganic silica precursor (SA@OISP) core/shell hierarchical nanostructure, consisting of a sacrificial styrene-acrylate (SA) primary template, was fabricated using a sol-gel method; (2) the self-assembly of the nanostructures leads to SA@OISP nanospheres forming the high-quality hollow closed-pore silica antireflection coating (CHAR) by a dip-coating process and a subsequent calcination treatment. The resulting SA@OISP nanospheres have a mean diameter of 65.2 nm and contained a SA soft core with a mean diameter of approximately 54.8 nm and an organic-inorganic silica precursor (OISP) shell with a thickness of approximately 6-10 nm. Furthermore, the prepared CHAR film exhibited a high transmittance and good ruggedness. An average transmittance (TAV) of 97.64% was obtained, and the value is close to the ideal single-layered antireflection coating (98.09%) over a broad range of wavelengths (from 380 to 1100 nm). The CHAR film showed a stable TAV, with attenuation values of less than 0.8% and 0.43% after the abrasion test and the damp heat test, respectively. The conversion efficiency of the CHAR coating cover solar modules tends to be increased by 3.75%. The promising results obtained in this study suggest that the CHAR film was considered as an essential component of the solar module and were expected to provide additional solar energy harvest under extreme outdoor climates. PMID:27104837

  14. Broad Band Antireflection Coating on Zinc Sulphide Window for Shortwave infrared cum Night Vision System

    International Nuclear Information System (INIS)

    In state of art technology, integrated devices are widely used or their potential advantages. Common system reduces weight as well as total space covered by its various parts. In the state of art surveillance system integrated SWIR and night vision system used for more accurate identification of object. In this system a common optical window is used, which passes the radiation of both the regions, further both the spectral regions are separated in two channels. ZnS is a good choice for a common window, as it transmit both the region of interest, night vision (650 – 850 nm) as well as SWIR (0.9 – 1.7 μm). In this work a broad band anti reflection coating is developed on ZnS window to enhance the transmission. This seven layer coating is designed using flip flop design method. After getting the final design, some minor refinement is done, using simplex method. SiO2 and TiO2 coating material combination is used for this work. The coating is fabricated by physical vapour deposition process and the materials were evaporated by electron beam gun. Average transmission of both side coated substrate from 660 to 1700 nm is 95%. This coating also acts as contrast enhancement filter for night vision devices, as it reflect the region of 590 – 660 nm. Several trials have been conducted to check the coating repeatability, and it is observed that transmission variation in different trials is not very much and it is under the tolerance limit. The coating also passes environmental test for stability.

  15. Perfect anti-reflection from first principles

    Science.gov (United States)

    Kim, Kyoung-Ho; Q-Han Park

    2013-01-01

    Reducing unwanted reflections through impedance matching, called anti-reflection, has long been an important challenge in optics and electrical engineering. Beyond trial and error optimization, however, a systematic way to realize anti-reflection is still absent. Here, we report the discovery of an analytic solution to this long standing problem. For electromagnetic waves, we find the graded permittivity and permeability that completely remove any given impedance mismatch. We demonstrate that perfect broadband anti-reflection is possible when a dispersive, graded refractive index medium is used for the impedance-matching layer. We also present a design rule for the ultra-thin anti-reflection coating which we confirm experimentally by showing the anti-reflection behavior of an exemplary λ/25-thick coating made of metamaterials. This work opens a new path to anti-reflection applications in optoelectronic device, transmission line and stealth technologies.

  16. Ultraporous nanocrystalline TiO2-based films: synthesis, patterning and application as anti-reflective, self-cleaning, superhydrophilic coatings

    Science.gov (United States)

    Faustini, Marco; Grenier, Antonin; Naudin, Guillaume; Li, Ronghua; Grosso, David

    2015-11-01

    Crack-free, anatase-based optical coatings with a refractive index down to 1.27, a porosity up to 80 vol%, and a tunable thickness up to 1.5 μm were fabricated. The extraordinary stability of the porosity upon thermally induced crystallisation and template removal was attributed to the combined effects of the presence of 10% molar silica in the inorganic phase, a flash treatment at 500 °C, and the use of templates with different dimensions ranging from a few nanometers to 50 nm. The hierarchical porous system was directly patterned by UV lithography and used as multifunctional anti-reflective, self-cleaning coatings.Crack-free, anatase-based optical coatings with a refractive index down to 1.27, a porosity up to 80 vol%, and a tunable thickness up to 1.5 μm were fabricated. The extraordinary stability of the porosity upon thermally induced crystallisation and template removal was attributed to the combined effects of the presence of 10% molar silica in the inorganic phase, a flash treatment at 500 °C, and the use of templates with different dimensions ranging from a few nanometers to 50 nm. The hierarchical porous system was directly patterned by UV lithography and used as multifunctional anti-reflective, self-cleaning coatings. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr06466j

  17. Antireflection coating on germanium for dual channel (3-5 and 7.5-10.6 μm) thermal imagers

    Science.gov (United States)

    Ghosh, A.; Kant, P.; Bandyopadhyay, P. K.; Chandra, P.; Nijhawan, O. P.

    1999-02-01

    The dual channel thermal imager, operating in the 3-5 and 7.5-10.6 μm wavelength bands, is one of the latest achievements in instrumentation for target recognition and acquisition. While the 3-5 μm band is utilised for detecting hot objects such as engine exhausts of vehicles and fighter planes, the 7.5-10.6 μm band is employed for human bodies and objects at ambient temperatures. Many substrates are available which transmit in both these wavelength bands and their transmission can be enhanced by providing a suitable antireflection coating. In this paper, a broad band antireflection coating on germanium substrate is reported. The design approach involves achieving a continuously varying refractive index from that of the incident medium to the substrate. The continuously varying refractive index profile may be generated by using a sequence of thin layers of high and low refractive index materials. In this design a continuous refractive index profile is approximated by using a 13-layer stack of thorium fluoride and germanium as low and high index coating materials respectively. This coating conforms to environmental stability standards and shows an average transmission of 91% in 3-5 μm band and 94.5% in 7.5-10.6 μm band with a peak of 97% at 9 μm on 10 mm thick germanium substrate. Polycrystalline germanium has 2.5% absorption for a 10 mm thick substrate.

  18. Application of ionized cluster beam to anti-reflection coating of transmission windows

    International Nuclear Information System (INIS)

    High transmission films with high adhesive strength have been developed by using the ionized cluster beam (ICB) method. It was demonstrated that the acceleration voltage plays a very important role in controlling the optical quality of films. The transmission windows obtained are as follows. (1) The germanium (Ge) window coated with a zinc sulfide (ZnS) film obtained at 3 kV acceleration voltage had a transmittance of 96% at 10 μm wavelength and the adhesive strength of the film obtained was over 430 kg cm-2, which endured even after thermal treatment at 4600C. (2) The zinc sulfide (ZnS) window coated with lead fluoride (PbF2) film obtained by controlling the acceleration voltage within the range from 0.5 kV to zero had a transmittance of 95% at 10 μm wavelength and the adhesive strength of the film was 240 kg cm-2. (author)

  19. Sol gel TiO2 antireflection coatings for silicon solar cells

    OpenAIRE

    L.A. Dobrzański; M. Szindler

    2012-01-01

    Purpose: The aim of this paper was to investigate changes in surface morphology and optical reflection of thin films of titanium dioxide. Thin films were prepared using sol gel spin coating method.Design/methodology/approach: The microanalysis have been investigated by the Energy-dispersive X-ray spectroscopy EDS. The changes in surface topography was observed by the atomic force microscope AFM and scanning electron microscope SEM. The results of roughness have been prepared in the software X...

  20. Preparation and stress evolution of sol-gel SiO2 antireflective coatings for small-size anisotropic lithium triborate crystals

    Science.gov (United States)

    Tian, Bingtao; Wang, Xiaodong; Niu, Yanyan; Zhang, Jinlong; Zhang, Qinghua; Zhang, Zhihua; Wu, Guangming; Zhou, Bin; Shen, Jun

    2016-04-01

    Lithium triborate (LiB3O5, LBO) crystal is now one of the most useful nonlinear optical materials for frequency conversion of high power lasers. The use of the crystal, however, has been hampered by the unavailability of antireflective (AR) coatings with high laser damage resistance. In this work, a "point contact" dip-coating method is developed to prepare sol-gel SiO2 AR coatings on small-size LBO crystals. Using this approach, we obtain a homogenous coating surface on an 8 mm×8 mm×3 mm LBO crystal. The stress measurements show that the stresses in sol-gel SiO2 coatings vary with the time of natural drying, which is beyond our expectation. The anisotropic Young's modulus of the LBO crystal and the different evolution tendency of the stress in the different SiO2 coating layers are found to be responsible for the crack of the double-layer AR coatings on anisotropic LBO crystal. Meanwhile, the resulting coatings on LBO crystal achieve a LIDT of over 15 J/cm2 (532 nm, 3ns) and the coated LBO is expected to have a transmittance of over 99% at 800 nm.

  1. Preparation and stress evolution of sol–gel SiO2 antireflective coatings for small-size anisotropic lithium triborate crystals

    Directory of Open Access Journals (Sweden)

    Bingtao Tian

    2016-04-01

    Full Text Available Lithium triborate (LiB3O5, LBO crystal is now one of the most useful nonlinear optical materials for frequency conversion of high power lasers. The use of the crystal, however, has been hampered by the unavailability of antireflective (AR coatings with high laser damage resistance. In this work, a “point contact” dip-coating method is developed to prepare sol–gel SiO2 AR coatings on small-size LBO crystals. Using this approach, we obtain a homogenous coating surface on an 8 mm×8 mm×3 mm LBO crystal. The stress measurements show that the stresses in sol–gel SiO2 coatings vary with the time of natural drying, which is beyond our expectation. The anisotropic Young’s modulus of the LBO crystal and the different evolution tendency of the stress in the different SiO2 coating layers are found to be responsible for the crack of the double-layer AR coatings on anisotropic LBO crystal. Meanwhile, the resulting coatings on LBO crystal achieve a LIDT of over 15 J/cm2 (532 nm, 3ns and the coated LBO is expected to have a transmittance of over 99% at 800 nm.

  2. Radiation sensitive developable bottom anti-reflective coatings (DBARC) for 193nm lithography: first generation

    Science.gov (United States)

    Toukhy, Medhat; Oberlander, Joseph; Mullen, Salem; Lu, PingHung; Neisser, Mark

    2007-03-01

    A first generation DBARC applicable for 1 st minimum 193nm lithography is described in this paper. The polymer used in this DBARC is insoluble in the casting solvent of the resist, which is propyleneglycolmonomethyletheracetate (PGMEA). Photo acid generator (PAG) and base extractions from the DBARC coating by the resist casting solvent were examined by the DBARC dissolution rates in the developer, before and after solvent treatments. Although the resist and the DBARC do not appear to intermix, strong interaction between the two is evident by their lithographic performance and dissolution rate study.

  3. Composite films prepared by plasma ion-assisted deposition (IAD) for design and fabrication of antireflection coatings in visible and near-infrared spectral regions

    Science.gov (United States)

    Tsai, Rung-Ywan; Ho, Fang C.

    1994-11-01

    Ion-assisted deposition (IAD) processes configured with a well-controlled plasma source at the center base of a vacuum chamber, which accommodates two independent e-gun sources, is used to deposition TiO2MgF2 and TiO2-SiO2 composite films of selected component ratios. Films prepared by this technology are found durable, uniform, and nonabsorbing in visible and near-IR regions. Single- and multilayer antireflection coatings with refractive index from 1.38 to 2.36 at (lambda) equals 550 nm are presented. Methods of enhancement in optical performance of these coatings are studied. The advantages of AR coatings formed by TiO2-MgF2 composite films over those similar systems consisting of TiO2-SiO2 composite films in both visible and near-IR regions are also presented.

  4. Optimal design and fabrication method for antireflection coatings for P-polarized 193 nm laser beam at large angles of incidence (68°-74°).

    Science.gov (United States)

    Jin, Jingcheng; Jin, Chunshui; Li, Chun; Deng, Wenyuan; Chang, Yanhe

    2013-09-01

    Most of the optical axes in modern systems are bent for optomechanical considerations. Antireflection (AR) coatings for polarized light at oblique incidence are widely used in optical surfaces like prisms or multiform lenses to suppress undesirable reflections. The optimal design and fabrication method for AR coatings with large-angle range (68°-74°) for a P-polarized 193 nm laser beam is discussed in detail. Experimental results showed that after coating, the reflection loss of a P-polarized laser beam at large angles of incidence on the optical surfaces is reduced dramatically, which could greatly improve the output efficiency of the optical components in the deep ultraviolet vacuum range. PMID:24323257

  5. Effect of diffuse roof cover with anti-reflection coating for roses; Effect van diffuus kasdek met Anti Reflectie coating bij Roos

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Victoria, N.; Kempkes, F.

    2012-10-15

    The rose Red Naomi was cultivated in two greenhouses at Wageningen UR Greenhouse Horticulture in Bleiswijk, Netherlands (August 2010 - September 2011). One greenhouse covered with normal float glass; the other with AR coated diffuse glass (70% haze). This Anti-Reflection coating on both glass sides compensated for the loss in light transmission caused by the diffusing structure in the glass. The diffuse AR glass lead to a 5.2% higher production (>6.1% fresh weight). Sunscreens were necessary in spring and summer to avoid high light levels on the flower buds, as they cause very high bud temperatures leading to quality problems (blue petal edges and burnt leaf tips). The diffuse greenhouse cover allowed a 100 W/m{sup 2} higher screening threshold than the reference glass. This caused a 2.7% higher daily light integral, able to explain part of the extra production obtained. Part of the extra production achieved can not be explained by the measured factors as no differences were found in the amount of light intercepted by the crop or in leaf photosynthesis under both cover types. The light under the diffuse AR cover was nevertheless much smoother, so the crop seemed to suffer less (lower bud temperatures and less burned leaf tips), and this should provide an explanation for the rest of the extra production. The cover properties did not influence disease development (powdery mildew). The obtained extra production makes the tempered, diffuse glass with Anti Reflection coating on both sides economically feasible [Dutch] Tussen augustus 2010 en september 2011 is bij Wageningen UR Glastuinbouw het effect van diffuus glas, met dubbelzijdige AR coating, op de productie en energiegebruik van roos 'Red Naomi' onderzocht. Onder het diffuse glas werden 5,2% meer bloemtakken geproduceerd, deze rozen waren ook iets langer en zwaarder (6,1% meer versgewicht). Dit verschil kan deels verklaard worden doordat er onder het diffuse glas pas bij hogere stralingsniveau

  6. Effects of the chemical bonding on the optical and mechanical properties for germanium carbide films used as antireflection and protection coating of ZnS windows

    Science.gov (United States)

    Hu, Chaoquan; Zheng, Weitao; Tian, Hongwei; LeXu; Jiang, Qing

    2006-05-01

    Germanium carbide (Ge1-xCx) films have been prepared by RF reactive sputtering a pure Ge(111) target at different flow rate ratios of CH4/(CH4+Ar) in a CH4/Ar mixture discharge, and it has been found that the composition, chemical bonding, optical and mechanical properties of Ge1-xCx films are remarkably influenced by the flow rate ratio of CH4/(CH4+Ar). The effects of the chemical bonding on the optical and mechanical properties of the Ge1-xCx films have been explored. In addition, an antireflection Ge1-xCx double-layer coating deposited on both sides of the ZnS substrate wafer has been developed for application as an infrared window. It is shown that the transmittance in the wavelength region between 8 and 12 µm and the hardness of the ZnS substrate have been significantly improved by the double-layer coating.

  7. Design and preparation of frequency doubling antireflection coating with different thicknesses of interlayer for LiB3O5 crystal

    Institute of Scientific and Technical Information of China (English)

    Zhenxia Deng; Huihui Gao; Lianjun Xiao; Hongbo He; Zhengxiu Fan; Jianda Shao

    2007-01-01

    Design and preparation of frequency doubling antireflection coating with different thicknesses of interlayer were investigated for LiB3O5 (LBO) substrate. The design was based on the vector method. The thickness of the inserted SiO2 interlayer could be changed in a wide range for the four-layer design with two zeros at 1064 and 532 nm. The coatings without any interlayer and with 0.1 quarter-wave (λ/4), 0.3 λ/4, 0.5 λ/4 SiO2 interlayer were deposited respectively on LBO by using electron beam evaporation technique.All the prepared coatings with SiO2 interlayer indicated satisfying optical behavior. This expanded our option for the thickness of an interlayer when coating on LBO substrate. The prepared films with SiO2 interlayer showed better adhesion than that without any interlayer. The thickness of the interlayer affected the adhesion, the adhesion for the coating with 0.5 λ/4 SiO2 interlayer was not as good as the other two.

  8. Design and fabrication of a SiOx/ITO double-layer anti-reflective coating for heterojunction silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, D.; Digdaya, A.; Santbergen, R.; Van Swaaij, R.A.C.M.M.; Zeman, M. [Photovoltaic Materials and Devices, Delft University of Technology, P.O. Box 5031, 2600 GA Delft (Netherlands); Bronsveld, P.; Van Roosmalen, J.A.M.; Weeber, A.W. [ECN Solar Energy, P.O. Box 1, 1755 ZG Petten (Netherlands)

    2013-10-15

    In this contribution optical simulations of both flat and textured heterojunction silicon solar cells are presented and verified experimentally. Using Advanced Semiconductor Analysis (ASA) software, we optimize a double-layer anti-reflective (AR) coating, which has an additional SiOx film on the top of the existing indium tin oxide (ITO) coating. Our approach is based on maximizing the absorbance of the crystalline silicon (c-Si) wafer, which is strongly correlated with the solar cell's short circuit current (Jsc). Our simulations show that for a flat heterojunction silicon solar cell c-Si absorbance can increase by using a double-layer AR coating instead of a single-layer AR coating. As predicted by the simulations, experimental devices show corresponding Jsc increase, leading to the increase of the solar cell efficiency. On a textured heterojunction silicon solar cell the incident light travels an oblique path through the AR coating and we use an advanced ray-tracing model to optimize the single and double-layer AR coating for this case. Our simulations show that for the textured heterojunction silicon solar cell, reflection losses are lower but parasitic absorption losses in the ITO and amorphous silicon layers play a more important role. Using a double-layer AR coating not only reduces reflection losses further, but because a thinner ITO layer can be used it also reduces parasitic absorption losses. Experimentally, our textured heterojunction silicon solar cell with a double-layer AR coating shows that the Jsc (active area) of 40.5 mA/cm{sup 2} and an efficiency of 19.0%.

  9. Omnidirectional wavelength selective emitters/absorbers based on dielectric-filled anti-reflection coated two-dimensional metallic photonic crystals

    Science.gov (United States)

    Yeng, Yi Xiang; Chou, Jeffrey B.; Rinnerbauer, Veronika; Shen, Yichen; Kim, Sang-Gook; Joannopoulos, John D.; Soljačić, Marin; Čelanović, Ivan

    2014-08-01

    We demonstrate designs of dielectric-filled anti-reflection coated (ARC) two-dimensional (2D) metallic photonic crystals (MPhCs) capable of omnidirectional, polarization insensitive, wavelength selective emission/absorption. Up to 26% improvement in hemispherically averaged emittance/absorptance below the cutoff wavelength is observed for optimized hafnium oxide filled 2D tantalum (Ta) PhCs over the unfilled 2D Ta PhCs. The optimized designs possess high hemispherically averaged emittance/absorptance of 0.86 at wavelengths below the cutoff wavelength and low hemispherically averaged emittance/absorptance of 0.12 at wavelengths above the cutoff wavelength, which is extremely promising for applications such as thermophotovoltaic energy conversion, solar absorption, and infrared spectroscopy.

  10. Investigation of the degradation of the antireflection coatings of the nonlinear crystal under the action of the high average power laser radiation

    International Nuclear Information System (INIS)

    The analysis of the local heating role in the processes of the degradation of the antireflection coatings of the nonlinear crystals when they have been used in the CW and quasi-CW YAG lasers was carried out. The broad sample range of the oxide, nitride and fluoride films deposited on the LiNbO3, BaNaNbO5, LiIO3 KTP and BBO crystals was considered. Investigation of these samples was carried out under the intense heating of their surfaces by the action of the CO2 laser pulses. The analysis of the obtained results with account for the chemical reaction thermodynamics, thermotension and other factors is presented

  11. Design and Preparation of SiO2/TiO2/SiO2-TiO2 Antireflective Coatings with Excellent Abrasion-resistance and Transmittance via Sol-Gel Process

    Directory of Open Access Journals (Sweden)

    YE Long-Qiang, ZHANG Qing-Hua, ZHANG Yu-Lu, ZHANG Xin-Xiang, JIANG Bo

    2012-08-01

    Full Text Available Triple-layer broadband antireflective (AR coatings with excellent abrasion-resistance and transmittance were designed using the theory of optical coating design. And the designed coatings were prepared on K9 glass via Sol-Gel process in this work. SiO2 and TiO2 sols were prepared using tetraethylorthosilicate (TEOS and titanium tetraisopropoxide (TTIP as precursors, respectively, and hydrochloric acid as catalyst. It is found that the average transmittance of the AR coatings over the entire visible region can reach 98.7%, which is 7.1% higher than that at the blank K9 glass. Moreover the transmittance of the AR coating does not obviously decrease after abrasion test, showing the excellent abrasion-resistance of the AR coatings. Hexamethyldisiloxane (HMDS is further used to modify the surface of the AR coatings, which greatly improves the hydrophobicity of the coatings, and thus gives the AR coatings excellent environmental resistance.

  12. A novel method for crystalline silicon solar cells with low contact resistance and antireflection coating by an oxidized Mg layer

    Science.gov (United States)

    Lee, Jonghwan; Lee, Youn-Jung; Ju, Minkyu; Ryu, Kyungyul; Kim, Bonggi; Yi, Junsin

    2012-01-01

    One of the key issues in the solar industry is lowering dopant concentration of emitter for high-efficiency crystalline solar cells. However, it is well known that a low surface concentration of dopants results in poor contact formation between the front Ag electrode and the n-layer of Si. In this paper, an evaporated Mg layer is used to reduce series resistance of c-Si solar cells. A layer of Mg metal is deposited on a lightly doped n-type Si emitter by evaporation. Ag electrode is screen printed to collect the generated electrons. Small work function difference between Mg and n-type silicon reduces the contact resistance. During a co-firing process, Mg is oxidized, and the oxidized layer serves as an antireflection layer. The measurement of an Ag/Mg/n-Si solar cell shows that V oc, J sc, FF, and efficiency are 602 mV, 36.9 mA/cm2, 80.1%, and 17.75%, respectively. It can be applied to the manufacturing of low-cost, simple, and high-efficiency solar cells.

  13. Defect Band Luminescence Intensity Reversal as Related to Application of Anti-Reflection Coating on mc-Si PV Cells: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Guthrey, H.; Johnston, S.; Yan, F.; Gorman, B.; Al-Jassim, M.

    2012-06-01

    Photoluminescence (PL) imaging is widely used to identify defective regions within mc-Si PV cells. Recent PL imaging investigations of defect band luminescence (DBL) in mc-Si have revealed a perplexing phenomenon. Namely, the reversal of the DBL intensity in various regions of mc-Si PV material upon the application of a SiNx:H anti-reflective coating (ARC). Regions with low DBL intensity before ARC application often exhibit high DBL intensity afterwards, and the converse is also true. PL imaging alone cannot explain this effect. We have used high resolution cathodoluminescence (CL) spectroscopy and electron beam induced current (EBIC) techniques to elucidate the origin of the DBL intensity reversal. Multiple sub-bandgap energy levels were identified that change in peak position and intensity upon the application of the ARC. Using this data, in addition to EBIC contrast information, we provide an explanation for the DBL intensity reversal based on the interaction of the detected energy levels with the SiNx:H ARC application. Multiple investigations have suggested that this is a global problem for mc-Si PV cells. Our results have the potential to provide mc-Si PV producers a pathway to increased efficiencies through defect mitigation strategies.

  14. Silicon nitride anti-reflection coating on the glass and transparent conductive oxide interface for thin film solar cells and modules

    Science.gov (United States)

    Iwahashi, T.; Morishima, M.; Fujibayashi, T.; Yang, R.; Lin, J.; Matsunaga, D.

    2015-10-01

    Anti-reflection coating (ARC) is well known as an important technique to enhance solar cell performance. Typical ARC has been applied on the glass surface to reduce light reflection loss at the air/glass interface. However, reflection loss occurs not only at glass surface but also at other interfaces such as glass/transparent conductive oxide (TCO) interface. The refractive index of SiNx is tunable from 1.6 to 2.7, and the range from 1.7 to 2.0 is suitable for ARC at glass/TCO interface. In this study, we examined the AR effect of silicon nitride (SiNx) deposited by plasma enhanced chemical vapor deposition at the glass/TCO interface with thin film silicon solar cell and module. Reflectivity reduction of 1.6% for glass/ZnO substrate has been obtained with optimal SiNx layer, which contribute 2.0% gain in cell efficiency. Besides, we also confirmed the relative efficiency gain of around 2% for large-sized solar module, leading to a world-record large area stabilized module conversion efficiency of 12.34%.

  15. Measurements and simulations of the optical gain and anti-reflection coating modal reflectivity in quantum cascade lasers with multiple active region stacks

    International Nuclear Information System (INIS)

    We report spectrally resolved gain measurements and simulations for quantum cascade lasers (QCLs) composed of multiple heterogeneous stacks designed for broadband emission in the mid-infrared. The measurement method is first demonstrated on a reference single active region QCL based on a double-phonon resonance design emitting at 7.8 μm. It is then extended to a three-stack active region based on bound-to-continuum designs with a broadband emission range from 7.5 to 10.5 μm. A tight agreement is found with simulations based on a density matrix model. The latter implements exhaustive microscopic scattering and dephasing sources with virtually no fitting parameters. The quantitative agreement is furthermore assessed by measuring gain coefficients obtained by studying the threshold current dependence with the cavity length. These results are particularly relevant to understand fundamental gain mechanisms in complex semiconductor heterostructure QCLs and to move towards efficient gain engineering. Finally, the method is extended to the measurement of the modal reflectivity of an anti-reflection coating deposited on the front facet of the broadband QCL

  16. Measurements and simulations of the optical gain and anti-reflection coating modal reflectivity in quantum cascade lasers with multiple active region stacks

    Science.gov (United States)

    Bidaux, Y.; Terazzi, R.; Bismuto, A.; Gresch, T.; Blaser, S.; Muller, A.; Faist, J.

    2015-09-01

    We report spectrally resolved gain measurements and simulations for quantum cascade lasers (QCLs) composed of multiple heterogeneous stacks designed for broadband emission in the mid-infrared. The measurement method is first demonstrated on a reference single active region QCL based on a double-phonon resonance design emitting at 7.8 μm. It is then extended to a three-stack active region based on bound-to-continuum designs with a broadband emission range from 7.5 to 10.5 μm. A tight agreement is found with simulations based on a density matrix model. The latter implements exhaustive microscopic scattering and dephasing sources with virtually no fitting parameters. The quantitative agreement is furthermore assessed by measuring gain coefficients obtained by studying the threshold current dependence with the cavity length. These results are particularly relevant to understand fundamental gain mechanisms in complex semiconductor heterostructure QCLs and to move towards efficient gain engineering. Finally, the method is extended to the measurement of the modal reflectivity of an anti-reflection coating deposited on the front facet of the broadband QCL.

  17. Improvement in photovoltaic properties of silicon solar cells with a doped porous silicon layer with rare earth (Ce, La) as antireflection coatings

    International Nuclear Information System (INIS)

    The performance improvement of solar cells due to the formation of a porous silicon layer treated with rare earth (Ce, La) in the n+ emitter of silicon n+/p junctions has been investigated. The photovoltaic properties of the cells with and without treatment of the porous silicon layer are compared. From the reflection measurements, it was shown that the cells with treated PS layers have lower reflectivity value compared to cell with untreated PS layer. The main result is that the photovoltaic energy conversion efficiency of solar cells can be enhanced by using the treated porous silicon layers with the rare earth (Ce, La) as anti-reflection coatings. -- Highlights: • The reduction of optical loss in silicon (c-Si) solar cells attracts the attention of many researches to achieve high efficiencies. • To attain this aim, the treated PS layers with rare earth (La, Ce) are suggested to be used as an (ARC) of c-Si solar cell. • The result showed a decrease in the optical losses which can explain the improved photovoltaic properties

  18. Effect of substrate heating on the adhesion and humidity resistance of evaporated MgF{sub 2}/ZnS antireflection coatings and on the performance of high-efficiency silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guangchun; Zhao, Jianhua; Green, Martin A. [Photovoltaics Special Research Centre, University of New South Wales, Sydney, NSW (Australia)

    1998-02-27

    This paper reports experimental results with substrate heating during thermal evaporation of MgF{sub 2}/ZnS DLAR (double-layer antireflection) coatings. The higher substrate temperature significantly improves the adhesion and humidity resistance of such coatings, while marginally reducing the performance of high-efficiency silicon PERL (passivated emitter, rear locally diffused) cells. The optimum substrate temperature for the evaporation of such DLAR coatings on the PERL cells is about 150C. At this temperature, the DLAR coatings have good durability, but give only slightly reduced PERL cell performance compared to the unheated substrate case. This reduction in the PERL cell performance is believed due to the partial removal of the hydrogen passivation, which was introduced through a standard `alneal` (aluminium anneal) process

  19. Multi-layer coatings

    Energy Technology Data Exchange (ETDEWEB)

    Maghsoodi, Sina; Brophy, Brenor L.; Abrams, Ze' ev R.; Gonsalves, Peter R.

    2016-06-28

    Disclosed herein are coating materials and methods for applying a top-layer coating that is durable, abrasion resistant, highly transparent, hydrophobic, low-friction, moisture-sealing, anti-soiling, and self-cleaning to an existing conventional high temperature anti-reflective coating. The top coat imparts superior durability performance and new properties to the under-laying conventional high temperature anti-reflective coating without reducing the anti-reflectiveness of the coating. Methods and data for optimizing the relative thickness of the under-layer high temperature anti-reflective coating and the top-layer thickness for optimizing optical performance are also disclosed.

  20. The optimization of triple layer anti-reflection coatings and its application on solar cells%三层减反射膜的模拟及其在太阳电池中的应用

    Institute of Scientific and Technical Information of China (English)

    宫臣; 张静全; 冯良桓; 武莉莉; 李卫; 黎兵; 曾广根; 王文武

    2013-01-01

    The anti-reflection coatings with the structure of Al2O3/H4/MgF2 triple layer were prepared with electron beam evaporation technology on the glass substrate. The transmittance and surface morphology of the films were examined. The anti-reflection coating structure was optimized considering AMI. 5 spectrum and the spectroscopy response band of CdS/CdTe thin film solar cells through TFCALC software simulation. Then the optimized anti-reflection coatings were prepared on the CdTe thin film solar cells. It was found that the quantum efficiency of solar cells with anti-reflection coatings increase by 7. 3% than without, and the photoelectric conversion efficiency increased from 12. 5% to 13. 3%.%使用减反射膜层是提高太阳电池短路电流密度进而提高电池转换效率的有效手段之一.针对CdTe薄膜太阳电池的光谱响应范围,基于AM1.5辐照光谱,优化设计了MgF2/H4/Al2O3结构的减反射薄膜,使用电子束蒸发技术制备了该减反射膜,使用椭圆偏振仪、紫外/可见分光光度计、原子力显微镜分别测量了所制备薄膜的光学性质和表面形貌,对比分析了膜系结构理论模拟与实验测量结果.结果表明,使用该减反射薄膜后,电池的量子效率提高了7.3%;光电转换效率从12.5%提高到13.3%.

  1. Wet-recess process optimization of a bottom antireflective coating for the via-first dual-damascene scheme

    Science.gov (United States)

    Brakensiek, Nickolas L.; Kidd, Brian; Washburn, Carlton A.; Murphy, Earnest

    2004-05-01

    The via-first process is unique by the fact that a material is needed to fill the vias to some arbitrary value, with little or no isolated-dense via bias so that the underlying layer underneath the via is protected from the trench etch step. Secondly, this material may have to coat over the surface of the wafer with some chosen thickness again with minimum or no bias to maximize the trench photolithography process window. Finally, the material must be easily removed from the via after the trench etch with no residue, crowning, or fencing. The ideal via fill material would be able to perform all the above listed parameters, but no perfect solution exists yet. The etchback process that is discussed herein, called the solvent etchback (SOLVE) process bypasses these lengthy modules, will fit within today"s manufacturing processes and will have little impact on throughput of the photobay coating tools. The process utilizes industry standard photoresists solvents such as PGMEA, Ethyl Lactate, PGME and existing solvent prewet dispense nozzles in the BARC coater module. Also, this process only requires one material that can both fill the via and act as a BARC during the trench photo step with a user defined thickness on top the wafer that will minimize light reflections coming from the substrate. The process flow for the SOLVE process is: 1. Coat a wafer with a thick BARC to planarize the wafer and minimize isolated-dense bias. 2. Bake the BARC so that it is partially crosslinked. 3. Apply a solvent to the wafer and etchback the BARC to a thickness that suits the trench photo step. 4. Bake the BARC to fully crosslink the BARC. Process variables that can have an affect on the SOLVE process are the softbake temperature and time to modify the BARC thickness on the wafer. Dispense parameters that will modify the post-etch uniformity of the wafer include the dispense time, dispense spin speed and the IDI M450 dispense pressure. The repeatability of the process can be modified

  2. Antireflective nanostructured zinc oxide arrays produced by pulsed electrodeposition

    International Nuclear Information System (INIS)

    Conditions for the pulsed electrochemical deposition of nanostructured zinc oxide arrays with a certain morphology, crystal structure, and optical properties from aqueous electrolytes onto substrates of transparent electrically conducting tin dioxide and on single-crystal silicon wafers with built-in homojunctions are studied in order to develop antireflection coatings for solar cells. It is shown that it is possible to obtain single-layer planar antireflection coatings or arrays of nanorods of this material, both having the form of hexagonal prisms and exhibiting the moth-eye effect

  3. Space qualification of an antireflection coating on the surface of a ruled grating prism: increasing the throughput of the single-object slitless spectroscopy mode of NIRISS onboard JWST

    Science.gov (United States)

    Albert, Loïc.; Doyon, René; Kuzmenko, Paul J.; Little, Steve L.; Enzor, Greg S.; Maszkiewicz, Michael

    2014-07-01

    Grating prisms (grism) designed for near-infrared spectroscopy typically make use of high-refractive index materials such as zinc selenide (ZnSe), at the expense of large Fresnel losses ( 18%). Part of the loss can be recovered by using anti-reflection (AR) coatings. The technique is however considered risky when applied on the ruled surface of a grating, especially for a space application at cryogenic temperature. Such a grism, made of ZnSe and machined at Lawrence Livermore National Laboratory (LLNL) is mounted in the Near-Infrared Slitless Spectrograph (NIRISS) onboard the James Webb Space Telescope (JWST). Its Single Object Slitless Spectrograph (SOSS) observing mode uses the ZnSe grism and a cross-dispersing prism to produce R=700 spectra in orders 1 and 2 to cover the 0.6 to 2.5 microns spectral domain. The ZnSe grism is blazed at 1.23 microns, has a density of 54 lines/mm and its triangular grooves have a depth of 700 nm, a base of 18 microns, with facets angled at 1.9 degrees. Here, an AR coating produced by Thin Film Lab (TFL) and deposited on the ruled surface of a ZnSe grism sample was space qualified. Atomic force microscopy (AFM) showed no groove profile change pre/post coating despite the large relative thickness of the AR coating to that of the groove depth ( 35%). Also, the wavefront error map remained almost unchanged at lambda/8 (peak-to-valley at 632 nm) and survived unscathed through a series of three cryogenic cycles to 20 K. Finally, the transmission gain across our operating spectral range was almost as high as that for a unruled surface covered with the same AR coating (10-15%).

  4. Design, Preparation and Modification of Third-Harmonic Silica Antireflective Coatings with Different Thickness%不同厚度三倍频SiO2增透膜的设计、制备与改性

    Institute of Scientific and Technical Information of China (English)

    张雨露; 张欣向; 业海平; 晏良宏; 江波

    2012-01-01

    本文通过光学计算设计了具有不同厚度的三倍频增透膜.以氨水为催化剂、正硅酸乙酯(TEOS)为前驱体,通过溶胶-凝胶(Sol-Gel)技术制得SiO2溶胶;采用浸渍提拉法镀膜得到符合设计要求的三倍频增透膜.研究结果表明,增透膜的耐磨擦性能随着膜层厚度的增大而增大,本文制得的厚度达到200 nm以上的三倍频增透膜耐磨擦性能显著优于传统的1/4波长三倍频增透膜.此外,本文以甲基含氢硅油为膜表面修饰剂,提出一种全新的超快的表面疏水性改性的方法.经该方法处理后,增透膜由亲水膜转变为疏水膜,对水的接触角从23.4.增大至95.,增透膜的耐环境性显著提高.%Third-harmonic antireflective (AR) coatings with different thickness were designed via optical formula in this work. Using tetraethylorthosilicate (TEOS) as precursor and ammonia as catalyst, SiC>2 sol was prepared by sol-gel process. The designed AR coatings were obtained by dip-coating process. It is found that the abrasion-resistance of AR coatings increased with film thickness, indicating that the abrasion-resistance of third-harmonic AR coatings prepared in this work is much better than that of the traditional quarter-wave third-harmonic AR coating. In addition, a totally new and super-fast surface modification method was proposed by using methyl hydrogen silicone oil as modifier. The water contact angle of AR coating increased from 23.4° to 95° after the surface modification.

  5. Scaling up the neutral solution antireflection process

    Energy Technology Data Exchange (ETDEWEB)

    Wirtenson, G.R.; Brown, N.J.; Cook, L.M.

    The neutral solution process (NSP) for chemically producing antireflection coatings has been scaled up from 24 cm and used successfully to treat components as large as 90 cm diameter. Since the process is primarily determined by diffusion through the surface, it has proven to be relatively insensitive to fluid flow effects which influence the chemical concentration buildup at the surface. Large parts visually appear more uniform than small parts processed in model tanks. The major problems encountered have been associated with using plastic support components beyond their normal temperature limits and with handling parts to the required cleanliness outside of a clean room environment.

  6. Optimization of the genetic operators and algorithm parameters for the design of a multilayer anti-reflection coating using the genetic algorithm

    Science.gov (United States)

    Patel, Sanjaykumar J.; Kheraj, Vipul

    2015-07-01

    This paper describes a systematic investigation on the use of the genetic algorithm (GA) to accomplish ultra-low reflective multilayer coating designs for optoelectronic device applications. The algorithm is implemented using LabVIEW as a programming tool. The effects of the genetic operators, such as the type of crossover and mutation, as well as algorithm parameters, such as population size and range of search space, on the convergence of design-solution were studied. Finally, the optimal design is obtained in terms of the thickness of each layer for the multilayer AR coating using optimized genetic operators and algorithm parameters. The program is successfully tested to design AR coating in NIR wavelength range to achieve average reflectivity (R) below 10-3 over the spectral bandwidth of 200 nm with different combinations of coating materials in the stack. The random-point crossover operator is found to exhibit a better convergence rate of the solution than single-point and double-point crossover. Periodically re-initializing the thickness value of a randomly selected layer from the stack effectively prevents the solution from becoming trapped in local minima and improves the convergence probability.

  7. Review of modern techniques to generate antireflective properties on thermoplastic polymers

    Science.gov (United States)

    Schulz, Ulrike

    2006-03-01

    Modern optical applications need solutions for providing polymer surfaces with antireflective properties. The problems involved in coating comprise thermal limitations, incompatible mechanical properties of coating and substrate materials, and interaction between polymers and plasma. As an alternative for coating, antireflective properties on polymers can also be obtained by hot embossing or by ion etching of surface structures. My objective is to provide the criteria for choosing suitable deposition or structuring methods based on an understanding of plasma-, radiation-, and ion-induced surface phenomena; material compatibility; mechanical and environmental performance; and cost issues. The potential to produce antireflective interference coatings is documented for plasma-enhanced physical- and chemical-vapor-deposition methods, including modern hybrid techniques, as well as for solgel wet-chemical processes. The review about state-of-the-art coatings focuses on the thermoplastic acrylic, polycarbonate, and cycloolefin polymers.

  8. Simulation and fabrication of SiO2/graded-index TiO2 antireflection coating for triple-junction GaAs solar cells by using the hybrid deposition process

    International Nuclear Information System (INIS)

    GaAs-based multi-junction solar cells (MJ-SCs) provide a wide solar-energy absorption-band (300–1800 nm), but designing and fabricating a broadband antireflection coating (ARC) are challenging. Because MJ-SCs are typically in a series that connects each subcell, the total output current is limited by the subcell that generates the smallest photocurrent. Thus, the ARC for MJ-SCs must be designed not only to obtain broadband absorption but also to minimize light reflection at the wavelength band of the current-limited cell. This study proposes a broadband SiO2/graded-index TiO2 ARC for improving the current-limited subcell performance by using a hybrid deposition (e-beam evaporation and spin-on coating). A bottom TiO2 layer and a top SiO2 layer were deposited through e-beam evaporation, but the middle TiO2 layer was deposited using spin-on coating because the refractive index values of the TiO2 films could be tuned by applying the spin speed. Therefore, the graded-index TiO2 layers were easily obtained using a hybrid deposition method. In addition, a suitable reflectance spectrum of an ARC structure for a middle-cell current-limited triple-junction (3-J) GaAs solar cell was simulated using commercial optical software. The photovoltaic current–voltage and external quantum efficiency (EQE) were measured and compared. The resulting improvements of a short-circuit current of 32.4% and conversion efficiency of 31.8% were attributed to an enhanced EQE of 32.97% as well as a low broadband reflectance exhibited on the middle cell of the 3-J GaAs solar cell with a SiO2/graded-index TiO2 ARC. - Highlights: • A broadband SiO2/graded-index TiO2 ARC obtained by a hybrid deposition • A suitable triple-layer ARC was simulated by a commercial optical software. • Optical reflection, photovoltaic I–V, and EQE of 3-J GaAs solar cell were characterized. • An increased Jsc of 32.4% and an increased η of 31.8% are obtained in the cell with proposed ARC

  9. Optical coating and nano-structuring on plastics

    Institute of Scientific and Technical Information of China (English)

    U.Schulz; P.Munzert; A.Kaless; N.Kaiser

    2005-01-01

    The coating of plastics for optical applications is intended to improve the mechanical durability of soft polymers and to serve an antireflection function. Usually a classic four-layer antireflection system is added on top of a single-layer hard coating. With needle optimisation,an alternative coating design has been developed. Plasma ion assisted deposition was used to deposit coatings upon polymers. Uniform antireflection and high scratch resistance have been achieved.

  10. Large-Area Crystalline Silicon Solar Cell Using Novel Antireflective Nanoabsorber Texturing Surface by Multihollow Cathode Plasma System and Spin-On Doping

    OpenAIRE

    Utpal Gangopadhyay; Sukhendu Jana; Sayan Das

    2013-01-01

    We present 11.7% efficient p-type crystalline silicon solar cells with a nanoscale textured surface and no dielectric antireflection coating. We propose nanocrystalline-like textured surface consisting of nanocrystalline columnar structures of diameters from 50 to 100 nm and depth of about 500 nm formed by reactive-ion etching (RIE) in multihollow cathode system. This novel nano textured surface acts as an antireflective absorbing surface of c-Si abbreviate as ARNAB (antireflective nanoabsorb...

  11. Development of antireflection coatings with a sup 6 LiF/ sup 6 sup 2 Ni multilayer converter for ultracold neutron detectors

    CERN Document Server

    Maier-Komor, P; Bergmaier, A; Dollinger, G; Paul, S; Schott, W

    2002-01-01

    High efficiency detectors for ultracold neutrons (UCN) are needed at the new high flux neutron source, Forschungsreaktor Muenchen II. In the development described, silicon PIN diodes were chosen to detect the alpha-particles or the tritons created in the reaction sup 6 Li(n,alpha)t. The high reflectance of UCN on sup 6 Li with its positive optical potential must be compensated by a material with negative optical potential. The isotope sup 6 sup 2 Ni was chosen for this. To avoid problems due to chemical reactions of Li with humidity, the compound sup 6 LiF was chosen. One hundred and fifty double layers of sup 6 LiF/ sup 6 sup 2 Ni had to be deposited by physical vapor deposition on silicon PIN diodes which had already been coated with 88 nm approx 77 mu g/cm sup 2 of sup 5 sup 8 Ni for reflection of the UCN. The theoretical optimal thickness of the sup 6 sup 2 Ni layers is 3 nm, and that of sup 6 LiF is 6 nm. Since expensive isotopes were involved, a small source-to-substrate distance had to be used, but wit...

  12. BDS Thin Film UV Antireflection Laser Damage Competition

    Energy Technology Data Exchange (ETDEWEB)

    Stolz, C J

    2010-10-26

    UV antireflection coatings are a challenging coating for high power laser applications as exemplified by the use of uncoated Brewster's windows in laser cavities. In order to understand the current laser resistance of UV AR coatings in the industrial and university sectors, a double blind laser damage competition was performed. The coatings have a maximum reflectance of 0.5% at 355 nm at normal incidence. Damage testing will be performed using the raster scan method with a 7.5 ns pulse length on a single testing facility to facilitate direct comparisons. In addition to the laser resistance results, details of deposition processes and coating materials will also be shared.

  13. Tunable Antireflection Layers for Planar Bolometer Arrays

    Science.gov (United States)

    Brown, Ari-David; Chuss, David; Woolack, Edward; Chervenak, James; Henry, Ross; Wray, James

    2007-01-01

    It remains a challenge to obtain high-efficiency coupling of far-infrared through millimeter radiation to large-format detector arrays. The conventional approach of increasing detector coupling is to use reflective backshorts. However, this approach often results in excessive systematic errors resulting from reflections off the backshort edge. An alternate approach to both increasing quantum efficiency and reducing systematics associated with stray light is to place an antireflective coating near the front surface of the array. When incorporated with a resistive layer and placed behind the detector focal plane, the AR coating can serve to prevent optical ghosting by capturing radiation transmitted through the detector. By etching a hexagonal pattern in silicon, in which the sizes of the hexes are smaller than the wavelength of incident radiation, it is possible to fabricate a material that has a controllable dielectric constant, thereby allowing for simple tunable optical device fabrication. To this end, we have fabricated and tested tunable silicon "honeycomb" AR layers and AR/resistive layer devices. These devices were fabricated entirely out of silicon in order to eliminate problems associated with differential contraction upon detector cooling.

  14. Development of new maskless manufacturing method for anti-reflection structure and application to large-area lens with curved surface

    Science.gov (United States)

    Yamamoto, Kazuya; Takaoka, Toshimitsu; Fukui, Hidetoshi; Haruta, Yasuyuki; Yamashita, Tomoya; Kitagawa, Seiichiro

    2016-03-01

    In general, thin-film coating process is widely applied on optical lens surface as anti-reflection function. In normal production process, at first lens is manufactured by molding, then anti-reflection is added by thin-film coating. In recent years, instead of thin-film coating, sub-wavelength structures adding on surface of molding die are widely studied and development to keep anti-reflection performance. As merits, applying sub-wavelength structure, coating process becomes unnecessary and it is possible to reduce man-hour costs. In addition to cost merit, these are some technical advantages on this study. Adhesion of coating depends on material of plastic, and it is impossible to apply anti-reflection function on arbitrary surface. Sub-wavelength structure can solve both problems. Manufacturing method of anti-reflection structure can be divided into two types mainly. One method is with the resist patterning, and the other is mask-less method that does not require patterning. What we have developed is new mask-less method which is no need for resist patterning and possible to impart an anti-reflection structure to large area and curved lens surface, and can be expected to apply to various market segments. We report developed technique and characteristics of production lens.

  15. Nanostructured Antireflective and Thermoisolative Cicada Wings.

    Science.gov (United States)

    Morikawa, Junko; Ryu, Meguya; Seniutinas, Gediminas; Balčytis, Armandas; Maximova, Ksenia; Wang, Xuewen; Zamengo, Massimiliano; Ivanova, Elena P; Juodkazis, Saulius

    2016-05-10

    Inter-related mechanical, thermal, and optical macroscopic properties of biomaterials are defined at the nanoscale by their constituent structures and patterns, which underpin complex functions of an entire bio-object. Here, the temperature diffusivity of a cicada (Cyclochila australasiae) wing with nanotextured surfaces was measured using two complementary techniques: a direct contact method and IR imaging. The 4-6-μm-thick wing section was shown to have a thermal diffusivity of α⊥ = (0.71 ± 0.15) × 10(-7) m(2)/s, as measured by the contact temperature wave method along the thickness of the wing; it corresponds to the inherent thermal property of the cuticle. The in-plane thermal diffusivity value of the wing was determined by IR imaging and was considerably larger at α∥ = (3.6 ± 0.2) × 10(-7) m(2)/s as a result of heat transport via air. Optical properties of wings covered with nanospikes were numerically simulated using an accurate 3D model of the wing pattern and showed that light is concentrated between spikes where intensity is enhanced by up to 3- to 4-fold. The closely packed pattern of nanospikes reduces the reflectivity of the wing throughout the visible light spectrum and over a wide range of incident angles, hence acting as an antireflection coating. PMID:27101865

  16. Antireflection-structured surfaces for mid-infrared entrance windows

    Science.gov (United States)

    Dubreuil, Didier; Harvey, Erol C.; Pigot, Claude; Rizvi, Nadeem H.

    1998-08-01

    SubWavelength Structured Surfaces (SWS), by synthesizing effective index of refraction, offer an attractive way to mimic antireflective coating effects. It is of particular interest for some IR materials of high index of refraction such as CdTe or KRS-5. These material are often used for entrance window in cryogenic IR instrument in the 20 microns band. For these materials, multilayer antireflective coatings provide limited performances in transmission, while expected performances of SWS can be very high even for a wavelength range covering both the N and Q atmospheric windows, from 7 microns to 28 microns. The SWS simulates a gradient index layer. Its main parameters are its pitch and its depth. The pitches required depend on the IR material index. For CdTe and KRS5, they are around 3 microns to work in N-band and Q-band and around 6 microns to work only on Q- band, and the depth required is around 10 microns to work till 28 microns. We have tried a new approach to realize these structures by using excimer laser ablation technique. We describe the used technique and our results for different materials such as CdTe, KRS5, CsBr and CsI. Antireflection structured surfaces on CdTe could offer an increase in transmission better than 25 percent at 24 microns. We measured a transmission efficiency of near 96 percent between 23 micrometers and 35 micrometers on KRS-5, and more than 95 percent between 18.5 micrometers and 35.5 micrometers on CsI.

  17. Development of broadband antireflection of high-index substrate using SiNx/SiO2

    Science.gov (United States)

    Lim, Kim Peng; Ng, Doris K. T.; Wang, Qian

    2016-03-01

    Broadband antireflection coatings are commonly required in many silicon or III-V compound semiconductor based optoelectronic devices such as solar cells, photodetectors, and image sensors so as to enhance light conversion efficiency. Conventional approach using a single-layer antireflection coating is simple and commonly used in industry but it has a limited working bandwidth. To achieve broadband or even omni-directional characteristics, structures using thick graded refractive index (GRIN) multilayers or nanostructured surfaces which have equivalent graded refractive index profile have been proposed and demonstrated. In this paper, we will show our development of broadband antireflection for high index substrate using SiNx/SiO2 via inductively coupled plasma chemical vapour deposition (ICPCVD). Global optimization of thin-film broadband antireflection coating using adaptive simulated annealing is presented. Unlike the conventional optical coating design which uses the refractive index of available materials, the optimization approach used here decides the optimal values of the refractive index as well as the thickness of each layer. The first thin-film material optimization is carried out on the ICP-CVD machine operating at low temperature of 250°C by tuning the SiH4/N2 gas ratio. The demonstrated double layer antireflection thin film reduces the average reflectance of Si surface from ~32% to ~3.17% at normal incidence for wavelength range from 400 to 1100 nm. This optical thin-film design and material development can be extended to optical wavelength filters and integrated micro-GRIN devices.

  18. Tailored antireflective biomimetic nanostructures for UV applications

    Energy Technology Data Exchange (ETDEWEB)

    Morhard, Christoph; Pacholski, Claudia; Spatz, Joachim P [Department of New Materials and Biosystems, Max Planck Institute for Metals Research, Heisenbergstrasse 3, D-70569 Stuttgart (Germany); Lehr, Dennis; Brunner, Robert; Helgert, Michael [Carl Zeiss Jena GmbH, Technology Center, Carl-Zeiss-Promenade 10, D-07745 Jena (Germany); Sundermann, Michael, E-mail: Pacholski@mf.mpg.de [Carl Zeiss Jena GmbH, Technology Center, Carl-Zeiss-Strasse 56, D-73447 Oberkochen (Germany)

    2010-10-22

    Antireflective surfaces composed of biomimetic sub-wavelength structures that employ the 'moth eye principle' for reflectance reduction are highly desirable in many optical applications such as solar cells, photodetectors and laser optics. We report an efficient approach for the fabrication of antireflective surfaces based on a two-step process consisting of gold nanoparticle mask generation by micellar block copolymer nanolithography and a multi-step reactive ion etching process. Depending on the RIE process parameters nanostructured surfaces with tailored antireflective properties can easily be fabricated that show optimum performance for specific applications.

  19. 碱/酸两步催化法制备耐候性SiO2增透膜的研究%Preparation and Characterization of Environment-Resistant Silica Antireflective Coating by Base/Acid Two-Step Catalyzed Sol-Gel Process

    Institute of Scientific and Technical Information of China (English)

    业海平; 张欣向; 肖波; 晏良宏; 江波

    2011-01-01

    Antireflective (AR) coatings with high transmittance and abrasion-resistance were prepared by a two-step base/acid catalyzed sol-gel process using tetraethylorthosilicate (TEOS) as precursor. It was found that addition of 50% acid-catalyzed SiO2 in the sol afforded the AR coatings relatively high transmittance and enhanced abrasion-resistance. It provided the AR coating with highest transmittance while the mole ratio of nH2O/nHCl was 1∶0.001 0. The water contact angle of base/acid two-step catalyzed AR coating was 11.3°, in this work,hexamethyldisiloxane (HMDS) was further used to modify the hydrophobicity of AR coatings. After HMDS treatment, the hydroxyl groups of AR coating were replaced by -OSi (CH3)3, which greatly increases the hydrophobicity of the coating, affording HMDS modified AR coating excellent environment resistance.%以正硅酸乙酯(TEOS)为先驱体,采用碱/酸两步催化溶胶-凝胶法制备出一种兼具碱催化增透膜的高透过率和酸催化增透膜的良好耐摩擦性能的优点的SiO2增透膜.对酸碱催化SiO2相对比例及酸催化时水含量的系统研究表明,当酸催化SiO2的含量为50%时,增透膜综合性能最好,即具有高透过率和高耐摩擦性;当nH2o/nHCI=1∶0.0010时,增透膜的透过率最高.碱/酸两步催化法制备的增透膜与水的接触角仅为11.3°,本文进一步用六甲基二硅氧烷(HMDS)对增透膜表面进行了修饰,修饰后增透膜的接触角提高至52.5°,增透膜的疏水性及环境稳定性得到较大的提高.

  20. Optical phenomena and antifrosting property on biomimetics slippery fluid-infused antireflective films via layer-by-layer comparison with superhydrophobic and antireflective films.

    Science.gov (United States)

    Manabe, Kengo; Nishizawa, Shingo; Kyung, Kyu-Hong; Shiratori, Seimei

    2014-08-27

    Sophisticated material interfaces generated by natural life forms such as lotus leaves and Nepenthes pitcher plants have exceptional abilities to resolve challenges in wide areas of industry and medicine. The nano- and microstructures inspired by these natural materials can repel various liquids and form self-cleaning coatings. In particular, slippery liquid-infused surfaces are receiving remarkable interest as transparent, nonfouling, and antifrosting synthetic surfaces for solar cells and optical devices. Here we focus on the transparency of lubricant-infused texture on antireflective films fabricated by layer-by-layer self-assembly that decrease light scattering, which is important to maintain device properties. A slippery fluid-infused antireflective film composed of chitin nanofibers less than 50 nm in diameter prevented light scattering at the long-wavelength side by Rayleigh scattering to achieve 97.2% transmittance. Moreover, films composed of the same materials demonstrated three different morphologies: superhydrophilicity with antireflection, superhydrophobicity, and omniphobicity, mimicking the biological structures of moth eyes, lotus leaves, and pitcher plants, respectively. The effect of thermal changes on the ability of each film to prevent frost formation was investigated. The slippery fluid-infused antireflective film showed effective antifrosting behavior. PMID:25093243

  1. Perfect anti-reflection from first principles

    OpenAIRE

    Kim, Kyoung-Ho; Q-Han Park

    2013-01-01

    Reducing unwanted reflections through impedance matching, called anti-reflection, has long been an important challenge in optics and electrical engineering. Beyond trial and error optimization, however, a systematic way to realize anti-reflection is still absent. Here, we report the discovery of an analytic solution to this long standing problem. For electromagnetic waves, we find the graded permittivity and permeability that completely remove any given impedance mismatch. We demonstrate that...

  2. Design and fabrication of infrared antireflecting bi-periodic micro-structured surfaces

    Science.gov (United States)

    Bouffaron, R.; Escoubas, L.; Simon, J. J.; Torchio, Ph.; Flory, F.; Berginc, G.; Masclet, Ph.; Perret, C.; Schiavone, P.

    2008-04-01

    Broadband antireflection properties of material surfaces are of primary interest for a wide variety of applications: to enhance the efficiency of photovoltaic cells, to increase the sensitivity of photodetectors, to improve the performance of light emitting diodes, etc... In the past, broadband antireflection multilayer coatings were widely used and recently very low refractive index materials in thin film form have been fabricated by several groups. The research work presented in this paper aims at modeling and fabricating bi-periodic micro-structured silicon surfaces exhibiting broadband antireflection properties in the infrared range. These structures of pyramidal shape, which typical dimensions are smaller than the wavelength, are not in the Effective Medium Theory (EMT) validity domain. The optimization of the optical properties of such patterned surfaces needs a fully Finite Difference Time Domain (FDTD) rigorous description of light propagation phenomena. The influence of various opto-geometrical parameters such as period, depth, shape of the pattern is examined. The antireflective properties of such bi-periodic patterned surfaces is then discussed using the photonic crystal theory and photonic band diagrams description. The structure is considered as a two dimensional periodic structure with a nonuniform third dimension. Correlations between the density of Bloch modes, flatness of dispersion curves and the surface reflectance are presented. The last part of this paper is devoted to the presentation of the fabrication and the characterization of the structures. Low cost and large surface processing techniques are proposed using wet anisotropic etching through a silica mask obtained by photolithography or nanoimprinting.

  3. Texturing of the Silicon Substrate with Nanopores and Si Nanowires for Anti-reflecting Surfaces of Solar Cells

    Directory of Open Access Journals (Sweden)

    A.A. Druzhinin

    2015-06-01

    Full Text Available The paper presents the prospects of obtaining a functional multi-layer anti-reflecting coating of the front surface of solar cells by texturing the surface of the silicon by electrochemical etching. The physical model of the "Black Si" coating with discrete inhomogeneity of the refractive index and technological aspects of producing of "Black Si" functional anti-reflecting coatings were presented. The investigation results of the spectral characteristics of the obtained multilayer multiporous "Black Si" coatings for silicon solar cells made by electrochemical etching are presented. The possibility of creating the texture on a silicon wafer surface using silicon nanowires and ordered nanopores obtained by metal-assisted chemical etching was shown.

  4. Coatings.

    Science.gov (United States)

    Anderson, Dennis G.

    1989-01-01

    This review covers analytical techniques applicable to the examination of coatings, raw materials, and substrates upon which coatings are placed. Techniques include chemical and electrochemical methods, chromatography, spectroscopy, thermal analysis, microscopy, and miscellaneous techniques. (MVL)

  5. Antireflective silica thin films with super water repellence via a solgel process.

    Science.gov (United States)

    Xu, Yao; Fan, Wen Hao; Li, Zhi Hong; Wu, Dong; Sun, Yu Han

    2003-01-01

    A solgel process was developed, through which silica films possessing both high antireflection and super water repellence were obtained. In this process, methyl-modified SiO2 sols synthesized by colloidal suspension of SiO2 particles and hexamethyldisilazane (HMDS) were used to deposit spinning-coating films on optical glass substrates. On the resultant films the contact angle for water increased with the increasing amount of HMDS in the reaction mixture. The biggest contact angle was 165 degrees, and the lowest reflectivity on one-sided film reached 0.03%. The antireflections were high all the while. One advantage of this process is that neither a roughened surface nor fluoroalkyltrialkoxylsilane (FAS) is needed to obtained super water repellence. PMID:12518829

  6. Enhancement in broadband and quasi-omnidirectional antireflection of nanopillar arrays by ion milling.

    Science.gov (United States)

    Huang, Zhifeng; Hawkeye, Matthew M; Brett, Michael J

    2012-07-11

    A new technique is developed to fabricate biomimetic antireflection coatings (ARCs). This technique combines a bottom-up fabrication approach (glancing angle deposition, or GLAD) with a top-down engineering process (ion milling). The GLAD technique is first utilized to produce nanopillar arrays (NPAs) with broadened structures, which are subsequently transformed into biomimetic tapered geometries by means of post-deposition ion milling. This structure transformation, due to milling-induced mass redistribution, remarkably decreases reflection over a wide wavelength range (300-1700 nm) and field of view (angle of incidence index transition from the substrate to the air, which improves the impedance match and reduces reflection losses. Additionally, ion bombardment tends to alter the stoichiometry and diminish the crystallographic structure of the NPA materials. The broadband and quasi-omnidirectional antireflection observed establishes the strong competitiveness of this technique with the methods previously reported. PMID:22705498

  7. Broadband and omnidirectional anti-reflection layer for III/V multi-junction solar cells

    CERN Document Server

    Diedenhofen, Silke L; Haverkamp, Erik; Bauhuis, Gerard; Schermer, John; Rivas, Jaime Gómez; 10.1016/j.solmat.2012.02.022

    2012-01-01

    We report a novel graded refractive index antireflection coating for III/V quadruple solar cells based on bottom-up grown tapered GaP nanowires. We have calculated the photocurrent density of an InGaP-GaAs-InGaAsP-InGaAs solar cell with a MgF2/ZnS double layer antireflection coating and with a graded refractive index coating. The photocurrent density can be increased by 5.9 % when the solar cell is coated with a graded refractive index layer with a thickness of 1\\mu m. We propose to realize such a graded refractive index layer by growing tapered GaP nanowires on III/V solar cells. For a first demonstration of the feasibility of the growth of tapered nanowires on III/V solar cells, we have grown tapered GaP nanowires on AlInP/GaAs substrates. We show experimentally that the reflection from the nanowire coated substrate is reduced and that the transmission into the substrate is increased for a broad spectral and angular range.

  8. Antireflective Boundary Conditions for Deblurring Problems

    Directory of Open Access Journals (Sweden)

    Marco Donatelli

    2010-01-01

    Full Text Available This survey paper deals with the use of antireflective boundary conditions for deblurring problems where the issues that we consider are the precision of the reconstruction when the noise is not present, the linear algebra related to these boundary conditions, the iterative and noniterative regularization solvers when the noise is considered, both from the viewpoint of the computational cost and from the viewpoint of the quality of the reconstruction. In the latter case, we consider a reblurring approach that replaces the transposition operation with correlation. For many of the considered items, the anti-reflective algebra coming from the given boundary conditions is the optimal choice. Numerical experiments corroborating the previous statement and a conclusion section end the paper.

  9. Comparison of Base-catalyzed Silica Antireflective Coatings Modified by Different Surface Treatments of Water-NH3 and/or Hexamethyldisilazane Vapors%水氨或/和六甲基二硅氮烷表面处理碱催化二氧化硅增透膜结果的对比研究

    Institute of Scientific and Technical Information of China (English)

    霍艳芳; 罗荣辉; 苏永钢

    2013-01-01

    Aiming at the shortcoming that base-catalyzed quarter-wave silica antireflective coatings,prepared by sol-gel method,are porous and therefore low environment-resistant,water/NH3 vapor and/or hexamethyldisilazane vapor were utilized to modify the surface of these coatings to obtain high hydrophobicity and abrasion-resistance.Otherwise,comparison between different modified results from single vapor and combined vapors,were carried out to show the changes of coatings' physical properties and microstructures after different surface modifications and the influence of the treated order of combined vapors to the result coatings.According to the investigations,some conclusion can be drawn that water-ammonia vapor treatment facilitates the cross-link between hydroxyl groups in coatings,which reduces the film thickness,strengthens the abrasion-resistance,and simultaneously maintains the high transmittance; hexamethyldisilazane vapor treatment introduces methyl groups into coatings,making the polarity of coating surface and the interaction between particles decreased obviously,leading to poorer abrasion-resistance but fortunately,distinctly improved hydrophobicity; when coatings are treated by water-ammonia combined hexamethyldisilazane vapor,the water-ammonia vapor firstly strengthens the abrasion-resistance and meanwhile reduces the amount of hydroxyl groups which hindered the later hexamethyldisilazane vapor treatment,finally obtaining AR coatings with good abrasion-resistance and a certain extent of hydrophobicity; when coatings are treated by hexamethyldisilazane combined water-ammonia vapor,the hexamethyldisilazane vapor obviously improves the hydrophobicity but weakens the effect of water-ammonia vapor,resulting in a slight weaker abrasion-resistance compared to that after single water-ammonia vapor treatment.%针对溶胶-凝胶法制备的1/4波长二氧化硅增透膜耐环境性差的缺点,对其进行了水氨或/和六甲基二硅氮烷的表面处理,并对单

  10. Durable superhydrophobic and antireflective surfaces by trimethylsilanized silica nanoparticles-based sol-gel processing.

    Science.gov (United States)

    Manca, Michele; Cannavale, Alessandro; De Marco, Luisa; Aricò, Antonino S; Cingolani, Roberto; Gigli, Giuseppe

    2009-06-01

    We present a robust and cost-effective coating method to fabricate long-term durable superhydrophobic andsimultaneouslyantireflective surfaces by a double-layer coating comprising trimethylsiloxane (TMS) surface-functionalized silica nanoparticles partially embedded into an organosilica binder matrix produced through a sol-gel process. A dense and homogeneous organosilica gel layer was first coated onto a glass substrate, and then, a trimethylsilanized nanospheres-based superhydrophobic layer was deposited onto it. After thermal curing, the two layers turned into a monolithic film, and the hydrophobic nanoparticles were permanently fixed to the glass substrate. Such treated surfaces showed a tremendous water repellency (contact angle = 168 degrees ) and stable self-cleaning effect during 2000 h of outdoor exposure. Besides this, nanotextured topology generated by the self-assembled nanoparticles-based top layer produced a fair antireflection effect consisting of more than a 3% increase in optical transmittance. PMID:19466786

  11. Control of polarization effects by internal antireflection.

    Science.gov (United States)

    Knittl, Z

    1981-01-01

    Mouchart's theory of the buffer layer is reformulated in terms of internal antireflection and extended to general dielectric/metallic media. The all-dielectric case is then studied in oblique incidence as a means of depolarizing partial reflectors. Several procedures are indicated for the construction of buffering stacks which, when coupled with germinal stacks, balance out their p and s reflections at the given level. Examples of depolarized half-mirrors are presented. A novel version of the Argand diagram for thin films in oblique incidence is introduced during the analysis. PMID:20309073

  12. Al2O3 antireflection coatings for silicon solar cells

    OpenAIRE

    L.A. Dobrzański; M. Szindler

    2013-01-01

    Purpose: The aim of this paper was to investigate changes in surface morphology and optical properties of thin films of Al2O3. Thin films were prepared using atomic layer deposition (ALD) method.Design/methodology/approach: The microanalysis was investigated by the Energy-dispersive X-ray spectroscopy EDS. The changes in surface topography was observed by the atomic force microscope AFM XE-100 and scanning electron microscope SEM. The results of roughness was obtained by the software XEI Park...

  13. Questionable effects of antireflective coatings on inefficiently cooled solar cells

    DEFF Research Database (Denmark)

    Akhmatov, Vladislav; Galster, Georg; Larsen, Esben

    1998-01-01

    of the output power and efficiency curves throughout the day the coherence between technical parameters of the solar cells and the climate in the operation region is observed and examined. It is shown how the drop in output power around noon can be avoided by fitting technical parameters of the solar cells......A model for temperature effects in p-n junction solar cells is introduced. The temperature of solar cells and the losses in the solar cell junction region caused by elevating temperature are discussed. The model developed is examined for low-cost silicon solar cells. In order to improve the shape...

  14. High efficiency infrared antireflection coatings (ARCs) for space optics

    Science.gov (United States)

    Nagendra, C. L.; Thutupalli, G. K. M.; Mohan, S.

    1989-05-01

    The development of non-quarter-wave IR ARCs for the Ge optics of space electrooptic hardware is described. A novel design-optimization method is applied in which the geometrical thicknesses of the ARC layers are calculated analytically (as explained by Nagendra, 1987). Two ARCs are developed: a three-layer system (ThF4/Ge/ThF4) for use at 7-12 microns and a two-layer system (CdTe/CdSe) for 14-16 microns. The ARCs are deposited in a vacuum-evaporation facility and subjected to optical and durability testing. The results are presented in graphs, and it is demonstrated that the ARCs are durable and transparent over the desired wavelength range and have spectral transmittance characteristics in good agreement with the theoretically predicted values.

  15. Laser processing of solar cells with anti-reflective coating

    Energy Technology Data Exchange (ETDEWEB)

    Harley, Gabriel; Smith, David D.; Dennis, Tim; Waldhauer, Ann; Kim, Taeseok; Cousins, Peter John

    2016-02-16

    Contact holes of solar cells are formed by laser ablation to accommodate various solar cell designs. Use of a laser to form the contact holes is facilitated by replacing films formed on the diffusion regions with a film that has substantially uniform thickness. Contact holes may be formed to deep diffusion regions to increase the laser ablation process margins. The laser configuration may be tailored to form contact holes through dielectric films of varying thicknesses.

  16. Fabrication of sub-wavelength antireflective structure to enhance the efficiency of InGaAs solar cells

    Directory of Open Access Journals (Sweden)

    Yen-Yu Chou

    2014-08-01

    Full Text Available Large differences in the refractive index between semiconductors (Si, GaAs, etc. and air produces considerable Fresnel loss, which can seriously hinder the absorption of sunlight by photovoltaic solar cells. This study presents a cost-effective roller nanoimprinting technique for the fabrication of sub-wavelength structures (SWSs as an alternative to conventional anti-reflective coatings used to reduce reflectance in triple-junction InGaP/InGaAs/Ge solar cells. The proposed nanoimprinting technology uses a soft PDMS mold duplicated from a hard silicon template, which is fabricated using PS sphere lithography and dry etching processes. To evaluate the anti-reflective performance of SWSs, we employed rigorous coupled wave analysis (RCWA to simulate the propagation of electromagnetic plane waves in a GaAs substrate. Simulation results demonstrated a considerable reduction in reflectance resulting from a gradual change in the refractive index provided by SWSs. Photoelectric conversion efficiency was also increased.

  17. Wide-angle antireflection ZnO films on bullet-like nanostructures of multi-crystalline silicon

    International Nuclear Information System (INIS)

    Nanosphere lithography and antireflection coating techniques have been applied to fabricate wide-angle antireflection structures on multicrystalline silicon substrates. Self-assembled 550-nm SiO2 nanospheres were arranged periodically to act as a mask to block the inductively coupled plasma dry etching and form bulletlike nanostructures on the surface of the multicrystalline silicon wafer. Then a 65-nm-thick zinc oxide film was deposited on the nanostructures using the atomic layer deposition method. The results show that when applying the nanostructure with a ZnO film the average reflectivity of the multicrystalline silicon wafer can be decreased from 36% to 0.65% in the wavelength range from 400 nm to 850 nm for an incident angle of 8 deg. . When the incident angle reaches 60 deg. the average reflectivity of the sample becomes less than 4.6%.

  18. Optical thin films and coatings from materials to applications

    CERN Document Server

    Flory, Francois

    2013-01-01

    Optical coatings, including mirrors, anti-reflection coatings, beam splitters, and filters, are an integral part of most modern optical systems. This book provides an overview of thin film materials, the properties, design and manufacture of optical coatings and their use across a variety of application areas.$bOptical coatings, including mirrors, anti-reflection coatings, beam splitters, and filters, are an integral part of most modern optical systems. Optical thin films and coatings provides an overview of thin film materials, the properties, design and manufacture of optical coatings and their use across a variety of application areas. Part one explores the design and manufacture of optical coatings. Part two highlights unconventional features of optical thin films including scattering properties of random structures in thin films, optical properties of thin film materials at short wavelengths, thermal properties and colour effects. Part three focusses on novel materials for optical thin films and coatings...

  19. Anti-reflective nanoporous silicon for efficient hydrogen production

    Science.gov (United States)

    Oh, Jihun; Branz, Howard M

    2014-05-20

    Exemplary embodiments are disclosed of anti-reflective nanoporous silicon for efficient hydrogen production by photoelectrolysis of water. A nanoporous black Si is disclosed as an efficient photocathode for H.sub.2 production from water splitting half-reaction.

  20. Broadband antireflection nanodome structures on SiC substrate

    DEFF Research Database (Denmark)

    Ou, Yiyu; Zhu, Xiaolong; Møller, Uffe Visbech;

    2013-01-01

    Nanodome structures are demonstrated on the SiC substrate by using nanosphere lithography and dry etching. Significant surface antireflection has been observed over a broad spectral range from 400 nm to 1600 nm.......Nanodome structures are demonstrated on the SiC substrate by using nanosphere lithography and dry etching. Significant surface antireflection has been observed over a broad spectral range from 400 nm to 1600 nm....

  1. Coatings and Tints of Spectacle Lenses

    Directory of Open Access Journals (Sweden)

    H. Zeki Büyükyıldız

    2012-10-01

    Full Text Available Spectacle lenses are made of mineral or organic (plastic materials. Various coatings and tints are applied to the spectacle lenses according to the characteristic of the lens material, and for the personal needs and cosmetic purpose. The coatings may be classified in seven groups: 1 Anti-reflection coatings, 2 Hard coatings, 3 Clean coat, 4 Mirror coatings, 5 Color tint coating (one of coloring processes, 6 Photochromic coating (one of photochromic processes, and 7 Anti-fog coatings. Anti-reflection coatings reduce unwanted reflections from the lens surfaces and increase light transmission. Hard coatings are applied for preventing the plastic lens surface from scratches and abrasion. Hard coatings are not required for the mineral lenses due to their hardness. Clean coat makes the lens surface smooth and hydrophobic. Thus, it prevents the adherence of dust, tarnish, and dirt particles on the lens surface. Mirror coatings are applied onto the sunglasses for cosmetic purpose. Color tinted and photochromic lenses are used for sun protection and absorption of the harmful UV radiations. Anti-fog coatings make the lens surface hydrophilic and prevent the coalescence of tiny water droplets on the lens surface that reduces light transmission. (Turk J Ophthalmol 2012; 42: 359-69

  2. Simple fabrication of an antireflective hemispherical surface structure using a self-assembly method for the terahertz frequency range.

    Science.gov (United States)

    Kim, Dae-Seon; Kim, Dong-Ju; Kim, Dong-Hyun; Hwang, Sehyun; Jang, Jae-Hyung

    2012-07-01

    A hemispherical surface structure was fabricated on a sapphire substrate by utilizing a self-assembly and spin-coating process for a terahertz (THz) antireflection coating. The self-assembled glass spheres and spin-coated material led to a gradual change in the effective refractive index. The aspect ratio of the hemispherical surface structure was controlled easily by adjusting the thickness of the B-staged bisbenzocyclobutene used as a coating. The reflectance of the fabricated hemispherical surface structure, having a period of 140 μm, exhibited low reflectance and low Fabry-Perot resonance in a THz spectral range from 0.1 to 1.9 THz. PMID:22743514

  3. Simple, Fast, and Cost-Effective Fabrication of Wafer-Scale Nanohole Arrays on Silicon for Antireflection

    Directory of Open Access Journals (Sweden)

    Di Di

    2014-01-01

    Full Text Available A simple, fast, and cost-effective method was developed in this paper for the high-throughput fabrication of nanohole arrays on silicon (Si, which is utilized for antireflection. Wafer-scale polystyrene (PS monolayer colloidal crystal was developed as templates by spin-coating method. Metallic shadow mask was prepared by lifting off the oxygen etched PS beads from the deposited chromium film. Nanohole arrays were fabricated by Si dry etching. A series of nanohole arrays were fabricated with the similar diameter but with different depth. It is found that the maximum depth of the Si-hole was determined by the diameter of the Cr-mask. The antireflection ability of these Si-hole arrays was investigated. The results show that the reflection decreases with the depth of the Si-hole. The deepest Si-hole arrays show the best antireflection ability (reflection 600 nm, which was about 28 percent of the nonpatterned silicon wafer’s reflection. The proposed method has the potential for high-throughput fabrication of patterned Si wafer, and the low reflectivity allows the application of these wafers in crystalline silicon solar cells.

  4. Design and fabrication of antireflective GaN subwavelength grating structures using periodic silica sphere monolayer array patterning

    Science.gov (United States)

    Ko, Yeong Hwan; Yu, Jae Su

    2013-12-01

    We designed and fabricated gallium nitride (GaN) subwavelength grating (SWG) structures on GaN/sapphire via patterning using the periodic silica sphere monolayer array as an etch mask and a subsequent dry etching for efficient antireflection coatings. Theoretical optimization of GaN SWG structures was performed in terms of their geometrical parameters by the rigorous coupled-wave analysis simulation using a theoretical structural model. The bullet-like parabola-shaped SWGs with a large height-to-diameter ratio ( R H/D) yielded good broadband and wide-angle antireflective surface properties. Considering the R H/D, the GaN SWG structure using 320-nm silica spheres theoretically and experimentally exhibited the most efficient antireflection property because it provided a linearly graded effective refractive index profile with relatively long relaxation length. For various geometries of the fabricated GaN SWGs on GaN/sapphire, the calculated reflectance results showed a similar tendency with the experimental results.

  5. Antireflective characteristics of hemispherical grid grating

    Institute of Scientific and Technical Information of China (English)

    REN Zhibin; JIANG Huilin; LIU Guojun; SUN Qiang

    2005-01-01

    In this paper, the optical characteristics of new type hemispherical grid subwavelength grating are studied by using multi-level column structure approximation and rigorous coupled-wave analysis. This kind of grating could be fabricated by chemical methods, thus simplifying the fabrication technology of subwavelength gratings for visible light. By computer simulation and calculation, the hemispherical grid subwavelength gratings are proved to have antireflective characteristics. Two design schemes of this kind of grating are presented. In the first scheme, the grating could achieve a reflectivity as low as 3.4416×10-7, which can be adapted to 0.46―0.7 μm of visible waveband and ±12° incident angle field. In the second scheme, the grating can achieve a reflectivity as low as 3.112×10-4 and adapted to the whole visible waveband and ±23° incident angle field. The application field of the latter scheme is wider than that of the former. The results of this paper could provide reference for the applications of the hemispherical grid subwavelength gratings for the visible waveband.

  6. Fabrication of Antireflective Sub-Wavelength Structures on Silicon Nitride Using Nano Cluster Mask for Solar Cell Application

    Directory of Open Access Journals (Sweden)

    Lin Men-Ku

    2009-01-01

    Full Text Available Abstract We have developed a simple and scalable approach for fabricating sub-wavelength structures (SWS on silicon nitride by means of self-assembled nickel nanoparticle masks and inductively coupled plasma (ICP ion etching. Silicon nitride SWS surfaces with diameter of 160–200 nm and a height of 140–150 nm were obtained. A low reflectivity below 1% was observed over wavelength from 590 to 680 nm. Using the measured reflectivity data in PC1D, the solar cell characteristics has been compared for single layer anti-reflection (SLAR coatings and SWS and a 0.8% improvement in efficiency has been seen.

  7. Broadband-antireflective hybrid nanopillar array for photovoltaic application

    International Nuclear Information System (INIS)

    Subwavelength structures such as nanopillars, nanoholes, and nanodomes have recently attracted considerable attention as antireflective structures for solar cells. Recent studies on the optical property of nanopillar array revealed that the reflection minimum is related to the diameter, the pitch, and the height of nanopillars. Here, we investigate the “hybrid” nanopillar array, which is composed of different diameters of nanopillars. Finite differential time domain simulations revealed that the photogeneration in a hybrid nanopillar array is spatially heterogeneous: carriers are generated mainly in the narrower pillars for short-wavelength incident light and in the thicker pillars for long-wavelength light, respectively. Hybrid silicon nanopillar arrays fabricated by using electron beam lithography and dry etching show excellent broadband antireflection property. Hybrid nanopillar array is thus highly promising for next-generation antireflection for photovoltaic applications

  8. Optimized antireflective silicon nanostructure arrays using nanosphere lithography

    Science.gov (United States)

    Lee, Dohaeng; Bae, Jiwoong; Hong, Soonwook; Yang, Hwichul; Kim, Young-Beom

    2016-05-01

    Broadband optical antireflective arrays of sub-wavelength structures were fabricated on silicon substrates using colloidal nanosphere lithography in conjunction with reactive ion etching. The morphology of the nanostructures, including the shape, base diameter and height, was precisely controlled by modifying the conventional process of nanosphere lithography. We investigated their effects on the optical characteristics based on experimentally measured reflectance performance. The Si nanostructure arrays demonstrated optical antireflection performance with an average reflectance of about 1% across the spectral range from 300 to 800 nm, i.e. near-ultraviolet to visible wavelengths. This fabrication method can be used to create a large surface area and offers a promising approach for antireflective applications.

  9. Fabrication and performance of polymer-nanocomposite anti-reflective thin films deposited by RIR-MAPLE

    Energy Technology Data Exchange (ETDEWEB)

    Singaravelu, S.; Mayo, D. C.; Park, H-. K.; Schriver, K. E.; Klopf, John M. [W& M, JLAB; Kelley, Michael J. [W& M; Haglund, R. F. [VANDERBILT

    2014-07-01

    Design of polymer anti-reflective (AR) optical coatings for plastic substrates is challenging because polymers exhibit a relatively narrow range of refractive indices. Here, we report synthesis of a four-layer AR stack using hybrid polymer: nanoparticle materials deposited by resonant infrared matrix-assisted pulsed laser evaporation. An Er: YAG laser ablated frozen solutions of a high-index composite containing TiO2 nanoparticles and poly(methylmethacrylate) (PMMA), alternating with a layer of PMMA. The optimized AR coatings, with thicknesses calculated using commercial software, yielded a coating for polycarbonate with transmission over 97 %, scattering <3 %, and a reflection coefficient below 0.5 % across the visible range, with a much smaller number of layers than would be predicted by a standard thin film calculation. The TiO2 nanoparticles contribute more to the enhanced refractive index of the high-index layers than can be accounted for by an effective medium model of the nanocomposite.

  10. An Antireflective Nanostructure Array Fabricated by Nanosilver Colloidal Lithography on a Silicon Substrate

    Directory of Open Access Journals (Sweden)

    Park Seong-Je

    2010-01-01

    Full Text Available Abstract An alternative method is presented for fabricating an antireflective nanostructure array using nanosilver colloidal lithography. Spin coating was used to produce the multilayered silver nanoparticles, which grew by self-assembly and were transformed into randomly distributed nanosilver islands through the thermodynamic action of dewetting and Oswald ripening. The average size and coverage rate of the islands increased with concentration in the range of 50–90 nm and 40–65%, respectively. The nanosilver islands were critically affected by concentration and spin speed. The effects of these two parameters were investigated, after etching and wet removal of nanosilver residues. The reflection nearly disappeared in the ultraviolet wavelength range and was 17% of the reflection of a bare silicon wafer in the visible range.

  11. Antireflective indium-tin-oxide nanobranches for efficient organic solar cells

    Science.gov (United States)

    Ham, Juyoung; Park, Jae Yong; Dong, Wan Jae; Jung, Gwan Ho; Yu, Hak Ki; Lee, Jong-Lam

    2016-02-01

    Indium tin oxide (ITO) nanobranched structures with low reflectance have been designed for application to organic solar cells. The ITO nanobranches are deposited on the front surface of glass without damages to organic active layer by using an electron beam deposition. Through a finite-difference time-domain, we find that the field intensity in the glass region is enhanced with ITO nanobranches. Consequently, the number of incident photons induces strong absorption within the PTB7-PC70BM active layer, leading to the enhanced short circuit current density (Jsc). Compared with a flat device (power conversion efficiency (PCE) = 6.53%, Jsc = 13.3 mA/cm2), improved PCE of 7.09% is achieved in an antireflection coating, which is mainly due to the increased Jsc of 14.2 mA/cm2.

  12. An effective reflectance method for designing broadband antireflection films coupled with solar cells

    Institute of Scientific and Technical Information of China (English)

    Zhan Feng; He Ji-Fang; Shang Xiang-Jun; Li Mi-Feng; Ni Hai-Qiao; Xu Ying-Qiang; Niu Zhi-Chuan

    2012-01-01

    The solar spectrum covers a broad wavelength range,which requires that antireflection coating (ARC) is effective over a relatively wide wavelength range for more incident light coming into the cell.In this paper,we present two methods to measure the composite reflection of SiO2/ZnS double-layer ARC in the wavelength ranges of 300-870 nm (dualjunction) and 300-1850 nm (triple-junction),under the solar spectrum AM0.In order to give sufficient consideration to the ARC coupled with the window layer and the dispersion effect of the refractive index of each layer,we use multidimensional matrix data for reliable simulation.A comparison between the results obtained from the weighted-average reflectance (WAR) method commonly used and that from the effective-average reflectance (EAR) method introduced here shows that the optimized ARC through minimizing the effective-average reflectance is convenient and available.

  13. Improvement of adhesion between plastic substrates and antireflection layers by ion-assisted reaction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung Hwan; Cho, Jun-Sik; Koh, Seok-Keun; Kim, Donghwan

    2004-02-02

    Enhanced adhesion was observed between antireflection (AR) layers and polycarbonate (PC) substrates by irradiating the substrates with low-energy Ar ions in an O{sub 2} environment. The AR coating consisted of SiO{sub 2}/TiO{sub 2} multi-layers that were deposited by ion-beam sputtering. Improved adhesion was evidenced by a peeling test. Ion irradiation caused the surface characteristics to become more hydrophilic as measured by the water contact angle, which decreased from 76 deg. to 18 deg. after the ion irradiation. X-ray photoelectron spectroscopy analysis showed that the concentration of hydrophilic groups such as C=O and C-O increased as a result of the ion irradiation. The changes in surface roughness and in optical transmittance were negligible. The optical reflectance of the AR/PC structure was below 1% in the visible range.

  14. Broadband antireflection properties of thin heterogeneous dielectric films.

    Science.gov (United States)

    Shvartsburg, A B; Petite, G; Hecquet, P

    2000-12-01

    New exactly solvable flexible models of inhomogeneous thin film with smooth and deep variations of dielectric susceptibility epsilon(z) are presented. Formation of cutoff frequencies of such films (as well as the broadband antireflection), controlled by the profiles epsilon(z), is shown. The crucial role of gradients of epsilon(z) in the optics of strongly inhomogeneous media is emphasized. PMID:11140487

  15. Antireflecting sublayers for neutron thin film polarising mirrors

    International Nuclear Information System (INIS)

    Measurements of the neutron polarising capability of Iron/Cobalt thin film mirrors deposited onto various Gadolinium-rich antireflecting sublayers are presented and the results compared with theoretical predictions. Excellent results were obtained in the cold neutron region though a degradation in performance is predicted in the thermal region at wavelengths approximately 1A. (author)

  16. Yttrium oxide coatings for high power lasers at 351 nm

    International Nuclear Information System (INIS)

    Yttrium oxide has proven to be a useful coating material for high power UV lasers. In combination with silicon dioxide it produces an effective dual wavelength antireflection coating at 351 and 1054 nanometers which has good resistance to damage at both wavelengths. While a durable coating material, yttrium oxide may be removed safely from a lightly damaged optic and reapplied. Index inhomogeneity of the material is investigated as well as modification of the film structure with ion-assisted deposition

  17. Optical coatings for laser fusion applications

    International Nuclear Information System (INIS)

    Lasers for fusion experiments use thin-film dielectric coatings for reflecting, antireflecting and polarizing surface elements. Coatings are most important to the Nd:glass laser application. The most important requirements of these coatings are accuracy of the average value of reflectance and transmission, uniformity of amplitude and phase front of the reflected or transmitted light, and laser damage threshold. Damage resistance strongly affects the laser's design and performance. The success of advanced lasers for future experiments and for reactor applications requires significant developments in damage resistant coatings for ultraviolet laser radiation

  18. Surface Passivation and Antireflection Behavior of ALD on n-Type Silicon for Solar Cells

    Directory of Open Access Journals (Sweden)

    Ing-Song Yu

    2013-01-01

    Full Text Available Atomic layer deposition, a method of excellent step coverage and conformal deposition, was used to deposit TiO2 thin films for the surface passivation and antireflection coating of silicon solar cells. TiO2 thin films deposited at different temperatures (200°C, 300°C, 400°C, and 500°C on FZ n-type silicon wafers are in the thickness of 66.4 nm ± 1.1 nm and in the form of self-limiting growth. For the properties of surface passivation, Si surface is effectively passivated by the 200°C deposition TiO2 thin film. Its effective minority carrier lifetime, measured by the photoconductance decay method, is improved 133% at the injection level of  cm−3. Depending on different deposition parameters and annealing processes, we can control the crystallinity of TiO2 and find low-temperature TiO2 phase (anatase better passivation performance than the high-temperature one (rutile, which is consistent with the results of work function measured by Kelvin probe. In addition, TiO2 thin films on polished Si wafer serve as good ARC layers with refractive index between 2.13 and 2.44 at 632.8 nm. Weighted average reflectance at AM1.5G reduces more than half after the deposition of TiO2. Finally, surface passivation and antireflection properties of TiO2 are stable after the cofire process of conventional crystalline Si solar cells.

  19. Properties of conductive coatings for thermal control mirrors and solar cell covers

    Science.gov (United States)

    Joslin, D. E.; Kan, H. K. A.

    1975-01-01

    Conductive transparent coatings applied to the dielectric surfaces of a spacecraft offer the possibility of distributing charge uniformly over the entire spacecraft surface. Optical and electrical measurements of such a coating as a function of temperature are described. These results are used in considering the impact of a conductive coating on the absorptance of thermal control mirrors and on the transmittance of solar cell cover glass, which can be improved by the application of an antireflection coating.

  20. Graphene-Tapered ZnO Nanorods Array as a Flexible Antireflection Layer

    OpenAIRE

    Taeseup Song

    2015-01-01

    Flexible solar cells have drawn a great deal of attention due to their various advantages including deformable and wearable characteristics. In the solar cells, the antireflection layer plays an important role in the improvement in the conversion efficiency by increasing the light transmission and suppressing the Fresnel refraction. For the successful implantation of the antireflection layer into the flexible solar cells, the flexible mechanical property of the antireflection layer is also ne...

  1. Antireflection and SiO2 Surface Passivation by Liquid-Phase Chemistry for Efficient Black Silicon Solar Cells: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, H. C.; Oh, J.; Zhang, Y.; Kuznetsov, O. A.; Flood, D. J.; Branz, H. M.

    2012-06-01

    We report solar cells with both black Si antireflection and SiO2 surface passivation provided by inexpensive liquid-phase chemistry, rather than by conventional vacuum-based techniques. Preliminary cell efficiency has reached 16.4%. Nanoporous black Si antireflection on crystalline Si by aqueous etching promises low surface reflection for high photon utilization, together with lower manufacturing cost compared to vacuum-based antireflection coating. Ag-nanoparticle-assisted black Si etching and post-etching chemical treatment recently developed at NREL enables excellent control over the pore diameter and pore separation. Performance of black Si solar cells, including open-circuit voltage, short-circuit current density, and blue response, has benefited from these improvements. Prior to this study, our black Si solar cells were all passivated by thermal SiO2 produced in tube furnaces. Although this passivation is effective, it is not yet ideal for ultra-low-cost manufacturing. In this study, we report, for the first time, the integration of black Si with a proprietary liquid-phase deposition (LPD) passivation from Natcore Technology. The Natcore LPD forms a layer of <10-nm SiO2 on top of the black Si surface in a relatively mild chemical bath at room temperature. We demonstrate black Si solar cells with LPD SiO2 with a spectrum-weighted average reflection lower than 5%, similar to the more costly thermally grown SiO2 approach. However, LPD SiO2 provides somewhat better surface-passivation quality according to the lifetime analysis by the photo-conductivity decay measurement. Moreover, black Si solar cells with LPD SiO2 passivation exhibit higher spectral response at short wavelength compared to those passivated by thermally grown SiO2. With further optimization, the combination of aqueous black Si etching and LPD could provide a pathway for low-cost, high-efficiency crystalline Si solar cells.

  2. Graded index and randomly oriented core-shell silicon nanowires for broadband and wide angle antireflection

    Directory of Open Access Journals (Sweden)

    P. Pignalosa

    2011-09-01

    Full Text Available Antireflection with broadband and wide angle properties is important for a wide range of applications on photovoltaic cells and display. The SiOx shell layer provides a natural antireflection from air to the Si core absorption layer. In this work, we have demonstrated the random core-shell silicon nanowires with both broadband (from 400nm to 900nm and wide angle (from normal incidence to 60º antireflection characteristics within AM1.5 solar spectrum. The graded index structure from the randomly oriented core-shell (Air/SiOx/Si nanowires may provide a potential avenue to realize a broadband and wide angle antireflection layer.

  3. Giant efficiency enhancement of GaAs solar cells with graded antireflection layers based on syringelike ZnO nanorod arrays

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, Li-Ko; Lai, Kun-Yu; Lin, Guan-Jhong; Fu, Po-Han; Chang, Hung-Chih; Lin, Chin-An; He, Jr-Hau [Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University, Taipei (China)

    2011-07-15

    An effective antireflection coating of syringelike ZnO NRAs is demonstrated for GaAs solar cells. Energy conversion efficiency is significantly enhanced by up to 32%. GaAs is focussed on as a model system, but the hydrothermal growth of syringelike ZnO nanostructures is readily compatible with the existing processes in the photovoltaic industry, and highly applicable for various types of solar cells. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Efficiency improvement of silicon solar cells enabled by ZnO nanowhisker array coating

    OpenAIRE

    Yu, Xuegong; Wang, Dong; Lei, Dong; Li, Genhu; Yang, Deren

    2012-01-01

    An efficient antireflection coating is critical for the improvement of silicon solar cell performance via increased light coupling. Here, we have grown well-aligned ZnO nanowhisker (NW) arrays on Czochralski silicon solar cells by a seeding-growth two-step process. It is found that the ZnO NWs have a great effect on the macroscopic antireflection effect and, therefore, improves the solar cell performance. The ZnO NW array-coated solar cells display a broadband reflection suppression from 500 ...

  5. Structure of Antireflective Films with Si-O-P Bonds and Impact Factors on Its Performance

    Directory of Open Access Journals (Sweden)

    WANG Yan, WANG Hong-Ning, CHEN Ruo-Yu

    2014-06-01

    Full Text Available An antireflective (AR film was successfully prepared by dip-coating on silica glass substrate. During the preparation, aqueous colloidal silica (ACS was used as silica source, orthophosphoric acid as adhesion promoting agent and hydrogen peroxide as activating agent. The structure, formation mechanism and performance of the film were investigated by FTIR, XRD, FESEM, TEM and AFM. The hydrogen peroxide in silica sol repairs the surface Si-O- bonds of colloidal silica particles greatly. As a result, their stabilities and reaction activities are improved. During the heat-treatment of the film, the orthophosphoric acid is firstly transformed into the chain of metaphosphoric acid and subsequently reacted with surface Si-OH from colloidal silica particles and the substrate, resulting in the formation of the numerous Si-O-P cross-linkings and the stable silicophosphate gel structure. When molar ratio of H3PO4: H2O2: EtOH: SiO2 is 0.49: 0.52: 30: 1, the average transmittance of the film in the visible light is 98%, and the pencil hardness grade reaches 6H.

  6. Bio-inspired antireflective hetero-nanojunctions with enhanced photoactivity

    Science.gov (United States)

    Qi, Dianpeng; Zheng, Liyan; Cao, Xuebo; Jiang, Yueyue; Xu, Hongbo; Zhang, Yanyan; Yang, Bingjie; Sun, Yinghui; Hng, Huey Hoon; Lu, Nan; Chi, Lifeng; Chen, Xiaodong

    2013-11-01

    A bio-inspired antireflective hetero-nanojunction structure has been fabricated by the hydrothermal growth of ZnO nanorods on silicon micro-pyramids. It has been shown that this structure suppresses light reflection more effectively resulting in a high photocurrent response and good charge separation simultaneously. The strategy provides a means to enhance solar energy conversion.A bio-inspired antireflective hetero-nanojunction structure has been fabricated by the hydrothermal growth of ZnO nanorods on silicon micro-pyramids. It has been shown that this structure suppresses light reflection more effectively resulting in a high photocurrent response and good charge separation simultaneously. The strategy provides a means to enhance solar energy conversion. Electronic supplementary information (ESI) available: HRTEM image and XRD pattern of a ZnO nanorod; schematic representation of the photoanode behavior, as well as the concentration change of rhodamine 6G through the photodegradation process over many repeats. See DOI: 10.1039/c3nr04011a

  7. Optical characterization of anti reflective sol-gel coatings fabricated using dip coating method

    Science.gov (United States)

    Melninkaitis, A.; Juškevičius, K.; Maciulevičius, M.; Sirutkaitis, V.; Beganskienė, A.; Kazadojev, I.; Kareiva, A.; Perednis, D.

    2007-01-01

    In recent years, there has been a growing interest in further development of sol-gel method which can produce ceramics and glasses using chemical precursors at relative low-temperatures. The applications for sol-gel derived products are numerous. Department of General and Inorganic Chemistry with Laser Research Center of Vilnius University and Institute of Physics continues an ongoing research effort on the synthesis, deposition and characterization of porous solgel. Our target is highly optically resistant anti-reflective (AR) coatings for general optics and nonlinear optical crystals. In order to produce AR coatings a silica (SiO II) sol-gel has been dip coated on the set of fused silica substrates. The optical properties and structure of AR-coatings deposited from hydrolysed tetraethylorthosilicate (TEOS) sol were characterized in detail in this study. The influence of different parameters on the formation of colloidal silica antireflective coatings by dip-coating technique has been investigated. All samples were characterized performing, transmission electron microscopy, UV-visible spectroscopy, atomic force microscopy, ellipsometric, total scattering and laser-induced damage threshold measurements. Herewith we present our recent results on synthesis of sol-gel solvents, coating fabrication and characterization of their optical properties.

  8. Application of physical gradient index (Moth-Eye) structures to ALON windows as a durable anti-reflection treatment

    Science.gov (United States)

    Agarwal, Neeta; Goldman, Lee M.; Sastri, Suri A.; Ondercin, Robert J.; Kobrin, Paul

    2009-05-01

    The optical performance of windows and domes are subject to degradation from rain and sand erosion damage in harsh flight environments. While durable window and dome materials, such as ALON®, spinel and sapphire are more or less impervious to rain and sand erosion damage in the captive carry environments, the coatings use to provide antireflection (AR) function are not. Rain and/or sand erosion damage of the outer AR coating leads to degradation of the windows optical performance, even when the underlying window itself is not damaged. Surmet has been working on design and development of physical gradient index (Moth- Eye) structures based AR surfaces etched directly into the surface of the ALON substrate. By eliminating the need for less durable coating materials, these structures offer high optical performance without compromising durability. The difficulty of this approach is that the same durability that makes ALON impervious to erosion damage makes it very difficult to etch. Processes have been developed at Surmet which facilitate the etching of fine deep features into ALON surfaces required for broadband AR function. Recent results will be presented.

  9. Use of ZnO as antireflective, protective, antibacterial, and biocompatible multifunction nanolayer of thermochromic VO2 nanofilm for intelligent windows

    Science.gov (United States)

    Zhou, Huaijuan; Li, Jinhua; Bao, Shanhu; Li, Jian; Liu, Xuanyong; Jin, Ping

    2016-02-01

    A multifunctional VO2/ZnO bilayer film is designed and deposited by magnetron sputtering apparatus. The integration of the antireflective, antioxidative and anti-corrosion functions, and antibacterial performance makes the heterostructure film a promising candidate in the energy-saving smart window. The ZnO thin film as the antireflection layer can markedly boost the solar regulation efficiency (ΔTsol) from 7.7% to 12.2% and possesses excellent luminous transmittance (Tlum-L = 50.3%) in the low-temperature semiconductor phase. The ZnO layer as the protection barrier can not only protect VO2 thin film from oxidation to much toxic V2O5, but also decrease the release of V ions. Besides, the synergistic effect of releasing killing by Zn2+ ions and contact killing by ZnO NPs makes ZnO thin film an outstanding antibacterial coating. In terms of the biological safety, ZnO coating with appropriate film thickness can effectively attenuate the cytotoxicity of VO2 on human HIBEpiC cells. We hope this work can provide new insights for better designing of novel multifunctional VO2-based intelligent energy-saving windows.

  10. Broadband antireflection for a high-index substrate using SiNx/SiO2 by inductively coupled plasma chemical vapour deposition

    International Nuclear Information System (INIS)

    This paper presents the development of broadband antireflection coating for a high-index substrate such as Si using SiNx/SiO2 by inductively coupled plasma chemical vapour deposition (ICP-CVD). The thin-film design employs a simulated annealing method for a minimal average reflectance over the wavelength range and incidence angles involved, which gives the optimized refractive index and thickness of each layer of the thin-film stack under different layer numbers. Using ICP-CVD, the SiNx material system is optimized by tuning the SiH4/N2 gas ratio. The corresponding thin-film characterization shows the precise refractive index/film thickness control in deposition, and the deposited film also has a low absorption coefficient and smooth surface. The double-layer SiNx/SiO2 coating with the optimized refractive index and thickness for broadband antireflection is demonstrated experimentally. The average reflectance of the Si surface is reduced from ∼32% to ∼3.17% at normal incidence for a wavelength range from 400 to 1100 nm. (paper)

  11. Biomimetic ‘moth-eye’ anti-reflection boundary for graphene plasmons circuits

    International Nuclear Information System (INIS)

    In this paper we propose the anti-reflection boundary design for planar graphene plasmons (GPs) circuits based on biomimetic moth-eye structures. The anti-reflection functionalities are investigated by analytical effective medium theory combined with transfer matrix method and numerical finite element method. Both analytical and numerical methods have shown that average reflection losses of 1% can be achieved within the mid-infrared region. Moreover, for plasmons with a very wide incident angle, the performance of such anti-reflection boundary could still be maintained, achieving less than 1% reflection up to 60° incident angle. The proposed moth-eye anti-reflection boundary would be helpful for the future development of high integration GPs circuits. (paper)

  12. Y2O3: Eu3+, Tb3+ spherical particles based anti-reflection and wavelength conversion bi-functional films: Synthesis and application to solar cells

    International Nuclear Information System (INIS)

    Highlights: • Eu3+ and Tb3+ co-doped Y2O3 particles were successfully prepared. The as prepared particles can convert UV region photos to visible photons between 460 nm and 640 nm, which just matched the spectral response of most solar cells. • Y2O3 is not only a good photoluminescence host material, but also it has high corrosion resistivity, thermal stability, and transparency from violet to infrared light. Cooperated with SiO2 sols, it could realize a better anti-reflection property. • As a proof-of-concept application, the as prepared bi-functional films could effectively improve the photoelectric conversion efficiency by 0.23% compared to pure SiO2 AR coating film and 0.55% compared to glass. - Abstract: In this study, Eu3+ and Tb3+ co-doped Y2O3 particles were prepared via the simple, cost-effective urea homogeneous precipitation method without additives. The chosen particles were added in the SiO2 sols to get anti-reflection (AR) and wavelength conversion bi-functional films. Careful investigations were carried out to find the optimum preparation conditions and proper morphology. SEM images showed that the particle sizes reduced as metal ion/urea ratio decreased. Additionally, the extracted particles turned from sphere to lamellar type when the deionized water, which was used as solvent, reduced to a certain extent. The mechanisms of the morphology formation and diversification were proposed as well. The as prepared materials can convert UV region photos to visible photons between 460 nm and 640 nm, which just matched the spectral response of most solar cells. The spherical sample showed better luminescence performance than the one with lamellar morphology. In addition, the optical transmittance spectra indicated that the films adding spherical particles had better anti-reflective performance, and the best adding amount was 0.08 g. Finally, As a proof-of-concept application, the as prepared bi-functional films were used to test the standard

  13. Nature Inspired Surface Coatings

    Science.gov (United States)

    Rubner, Michael

    2011-04-01

    Materials Scientists more and more are looking to nature for clues on how to create highly functional surface coatings with exceptional properties. The fog harvesting capabilities of the Namib Desert beetle, the beautiful iridescent colors of the hummingbird, and the super water repellant abilities of the Lotus leaf are but a few examples of the amazing properties developed over many years in the natural world. Nature also makes extensive use of the pH-dependent behavior of weak functional groups such as carboxylic acid and amine functional groups. This presentation will explore synthetic mimics to the nano- and microstructures responsible for these fascinating properties. For example, we have demonstrated a pH-induced porosity transition that can be used to create porous films with pore sizes that are tunable from the nanometer scale to the multiple micron scale. The pores of these films, either nano- or micropores, can be reversibly opened and closed by changes in solution pH. The ability to engineer pH-gated porosity transitions in heterostructured thin films has led to the demonstration of broadband anti-reflection coatings that mimic the anti-reflection properties of the moth eye and pH-tunable Bragg reflectors with a structure and function similar to that found in hummingbird wings and the Longhorn beetle. In addition, the highly textured honeycomb-like surfaces created by the formation of micron-scale pores are ideally suited for the creation of superhydrophobic surfaces that mimic the behavior of the self-cleaning lotus leaf. The development of synthetic "backbacks" on immune system cells that may one day ferry drugs to disease sites will also be discussed.

  14. Electrochemical deposition of black nickel solar absorber coatings on stainless steel AISI316L for thermal solar cells

    OpenAIRE

    Lira-Cantú, Monica; Morales Sabio, Angel; Brustenga, Alex; Gómez-Romero, P.

    2005-01-01

    We report the electrochemical deposition of nanostructured nickel-based solar absorber coatings on stainless steel AISI type 316L. A sol–gel silica-based antireflection coating, from TEOS, was also applied to the solar surface by the dip-coating method. We report our initial results and analyze the influence of the stainless steel substrate on the final total reflectance properties of the solar absorber. The relation between surface morphology, observed by SEM and AFM, the comp...

  15. Graded index and randomly oriented core-shell silicon nanowires with broadband and wide angle antireflection for photovoltaic cell applications

    CERN Document Server

    Pignalosa, P; Qiao, L; Tseng, M; Yi, Yasha

    2011-01-01

    Antireflection with broadband and wide angle properties is important for a wide range of applications on photovoltaic cells and display. The SiOx shell layer provides a natural antireflection from air to the Si core absorption layer. In this work, we have demonstrated the random core-shell silicon nanowires with both broadband (from 400nm to 900nm) and wide angle (from normal incidence to 60\\degree) antireflection characteristics within AM1.5 solar spectrum. The graded index structure from the randomly oriented core-shell (Air/SiOx/Si) nanowires may provide a potential avenue to realize a broadband and wide angle antireflection layer.

  16. Design and preparation of binary-binary SnO2-ZnO:F/MgF2/SiO2 transparent conducting oxide coatings

    Directory of Open Access Journals (Sweden)

    S Hadavi

    2012-12-01

    Full Text Available   In this study, we prepared the binary-binary TCO compounds of SnO2-ZnO by the spray pyrolysis technique. We also investigated the role of MgF2/SiO2 antireflection coatings in reducing optical reflectance in the visible region of TCO. Before preparation , we simulated the optical transmition of the films for optimizing the layer thicknesses. The results of this study showed increasing of optical transmittance in the visible region of TCO by adding antireflection coating layers.

  17. Design and preparation of binary-binary SnO2-ZnO:F/MgF2/SiO2 transparent conducting oxide coatings

    OpenAIRE

    Hadavi, S; Z Shahedi

    2012-01-01

      In this study, we prepared the binary-binary TCO compounds of SnO2-ZnO by the spray pyrolysis technique. We also investigated the role of MgF2/SiO2 antireflection coatings in reducing optical reflectance in the visible region of TCO. Before preparation , we simulated the optical transmition of the films for optimizing the layer thicknesses. The results of this study showed increasing of optical transmittance in the visible region of TCO by adding antireflection coating layers.

  18. Broadband antireflection sub-wavelength structure of InGaP/InGaAs/Ge triple junction solar cell with composition-graded SiNx

    Science.gov (United States)

    Chung, Chen-Chen; Lo, Hsiao-Chieh; Lin, Yen-Ku; Yu, Hung-Wei; Tinh Tran, Binh; Lin, Kung-Liang; Chen, Yung Chang; Quan, Nguyen-Hong; Chang, Edward Yi; Tseng, Yuan-Chieh

    2015-05-01

    This work reports a fabrication strategy to improve the antireflective ability of a InGaP/GaAs/Ge triple-junction solar cell, by combining a nano-templating technique and a chemical-synthesis approach. SiH4 and N2 were used as ammonia-free reaction gases in a plasma-enhanced chemical vapor deposition (PECVD) to prepare Si3N4 as an original antireflective coating (ARC) layer with better chemical stability. Composition-graded SiNx was successfully integrated with sub-wavelength structure by modulating SiH4/N2 ratio during PECVD deposition, and followed by a controllable gold-nanoparticle masking technique on top of the solar cell. Finite-difference time-domain solution was employed to simulate and optimize the aspect-ratio of the ARC, under the condition of variable refractive index over a broad wavelength window, and followed by the masking technique to obtain the desired ARC dimension. This enabled a low light reflectance (advantages of structural optimization, better chemical stability and graded refractive index of the ARC. The solar cell’s performance was tested and showed great competitiveness to those of forefront studies, suggesting the feasibility of the proposed technology.

  19. Effective antireflection properties of porous silicon nanowires for photovoltaic applications

    KAUST Repository

    Najar, Adel

    2013-01-01

    Porous silicon nanowires (PSiNWs) have been prepared by metal-assisted chemical etching method on the n-Si substrate. The presence of nano-pores with pore size ranging between 10-50nm in SiNWs was confirmed by electron tomography (ET) in the transmission electron microscope (TEM). The PSiNWs give strong photoluminescence peak at red wavelength. Ultra-low reflectance of <5% span over wavelength 250 nm to 1050 nm has been measured. The finite-difference time-domain (FDTD) method has been employed to model the optical reflectance for both Si wafer and PSiNWs. Our calculation results are in agreement with the measured reflectance from nanowires length of 6 µm and 60% porosity. The low reflectance is attributed to the effective graded index of PSiNWs and enhancement of multiple optical scattering from the pores and nanowires. PSiNW structures with low surface reflectance can potentially serve as an antireflection layer for Si-based photovoltaic devices.

  20. Scattering analysis for random antireflective structures on fused silica in the ultraviolet.

    Science.gov (United States)

    Zhao, Jiaoling; Qi, Hongji; Wang, Hu; He, Hongbo; Zhang, Weili

    2015-11-15

    Random antireflective structures are fabricated on fused silica by the thermal dewetting process and reactive ion etching, which shows a broadband antireflective effect over the whole visible wavelength. However, the transmittance in the ultraviolet is limited by the scattering from the etched structures. A graded refractive index model ignoring the scattering in the visible range is applied to extract the etched profile. Then the Lubachevsky-Stillinger algorithm is used to reconstruct the random antireflective structures with the extracted profile. Bidirectional scattering distribution for the reconstructed structures is simulated with the finite-difference time-domain method, which indicates the importance of transmissive scattering the scattering directivity. The scattering directivity is explained well with an effective grating model. The period of the effective grating can guide the prepared technique in the ultraviolet. PMID:26565826

  1. Improved Antireflection Properties of an Optical Film Surface with Mixing Conical Sub wavelength Structures

    International Nuclear Information System (INIS)

    Based on finite difference time domain method, an optical film surface with mixing conical sub wavelength structures is numerically investigated to improve antireflection property. The mixing conical sub wavelength structure is combined with the pure periodic conical sub wavelength structures and the added small conical structures in the gap between the pure periodic conical sub wavelength structures. The antireflection properties of two types of sub wavelength structures with different aspect ratios in spectral range of 400- 800 nm are analyzed and compared. It is shown that, for the mixing type, the average reflectance is decreased and the variances of the reflectance are evidently smaller. When the added structure with a better aspect ratio exists, the average reflectance of the surface can be below 0.30%. Obviously, the antireflection properties of the optical film surface with mixing conical sub wavelength structures can be improved.

  2. Preparation of Scratch-Resistant Nano-Porous Silica Films Derived by Sol-Gel Process and Their Anti-reflective Properties

    Institute of Scientific and Technical Information of China (English)

    Guangming WU; Jun SHEN; Tianhe YANG; Bin ZHOU; Jue WANG

    2003-01-01

    Structural strengthening of the nano porous silica films has been reported. The films were prepared with a base/acid two-step catalyzed TEOS-based sol-gel processing and dip-coating, and then baked in the mixed gas of ammonia and water vapor. The silica films were characterized with TEM, AFM, FTIR, spectrophotometer, ellipsometer, and abrasion test, respectively. The experimental results have shown that the films have a nanostructure with a low refractive index and can form an excellent scratch-resistant broadband anti-reflectance. The two-step catalysis noticeably strengthens the films, and the mixed gas treatment further improves mechanical strength of the silica network. Finally the strengthening mechanism has been discussed.

  3. Development of porous antireflective films on soda-lime-silica glass

    International Nuclear Information System (INIS)

    Glass compositions were surveyed to identify candidates that could be heat-treated to produce an interconnected phaseseparated structure needed for porous antireflective films and which matched the viscosity-temperature characteristics needed for the float glass process. A glass composition of 10% Na2O, 10% CaO, and 80% SiO2 meets these criteria. Microstructural development and film-formation kinetics were characterized to permit definition of appropriate heat-treatment and selective dissolution processes. Broadband antireflective characteristics were developed on treated glass surfaces

  4. Antireflective Nanocomposite Based Coating on Crystalline Silicon Solar Cells for Building-Integrated Photovoltaic Systems

    OpenAIRE

    Gangopadhyay, Utpal; Jana, Sukhendu; Das, Sayan; Garain, Sutapa; Ray, Soma

    2013-01-01

    Building-integrated photovoltaic (BIPV) systems represent an interesting, alternative approach for increasing the available area for electricity production and potentially for further reducing the cost of solar electricity. In BIPV systems, the visual impression of a solar module becomes important, including its color. However, the range of solar cell colours and shapes currently on offer to architects and BIPV system designers is still very limited, and this is a barrier to the widespread us...

  5. Amorphous Silicon Compound Films for Surface Passivation and Antireflection Coating of Crystalline Silicon Solar Cells

    OpenAIRE

    Petres, Roman

    2010-01-01

    Chapter 1 gives an introductory overview of the current status of photovoltaics, with focus on crystalline silicon (c-Si) based technology. An essential contribution to the reduction of electricity generation costs at the solar module production level is to be expected mainly from reduced silicon consumption by using thinner wafers and/or employing cheaper silicon feedstock. Together with sufficient light trapping, the key factor to being able to exploit the combined cost reduction potential ...

  6. Two dimensional metallic photonic crystals for light trapping and anti-reflective coatings in thermophotovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    Shemelya, Corey; DeMeo, Dante F.; Vandervelde, Thomas E. [The Renewable Energy and Applied Photonics Laboratories, Electrical and Computer Engineering, Tufts University, Medford, Massachusetts 02155 (United States)

    2014-01-13

    We report the development of a front-side contact design for thermophotovoltaics that utilizes metallic photonic crystals (PhCs). While this front-side grid replacement covers more surface area of the semiconductor, a higher percentage of photons is shown to be converted to usable power in the photodiode. This leads to a 30% increase in the short-circuit current of the gallium antimonide thermophotovoltaic cell.

  7. Self-assembled nanolaminate coatings (SV)

    Energy Technology Data Exchange (ETDEWEB)

    Fan, H.

    2012-03-01

    Sandia National Laboratories (Sandia) and Lockheed Martin Aeronautics (LM Aero) are collaborating to develop affordable, self-assembled, nanocomposite coatings and associated fabrication processes that will be tailored to Lockheed Martin product requirements. The purpose of this project is to develop a family of self-assembled coatings with properties tailored to specific performance requirements, such as antireflective (AR) optics, using Sandia-developed self-assembled techniques. The project met its objectives by development of a simple and economic self-assembly processes to fabricate multifunctional coatings. Specifically, materials, functionalization methods, and associated coating processes for single layer and multiple layers coatings have been developed to accomplish high reflective coatings, hydrophobic coatings, and anti-reflective coatings. Associated modeling and simulations have been developed to guide the coating designs for optimum optical performance. The accomplishments result in significant advantages of reduced costs, increased manufacturing freedom/producibility, improved logistics, and the incorporation of new technology solutions not possible with conventional technologies. These self-assembled coatings with tailored properties will significantly address LMC's needs and give LMC a significant competitive lead in new engineered materials. This work complements SNL's LDRD and BES programs aimed at developing multifunctional nanomaterials for microelectronics and optics as well as structure/property investigations of self-assembled nanomaterials. In addition, this project will provide SNL with new opportunities to develop and apply self-assembled nanocomposite optical coatings for use in the wavelength ranges of 3-5 and 8-12 micrometers, ranges of vital importance to military-based sensors and weapons. The SANC technologies will be applied to multiple programs within the LM Company including the F-35, F-22, ADP (Future Strike Bomber

  8. Optically optimal wavelength-scale patterned ITO/ZnO composite coatings for thin film solar cells

    CERN Document Server

    Moreau, Antoine; Centeno, Emmanuel; Seassal, Christian

    2012-01-01

    A new methodology is proposed for finding structures that are, optically speaking, locally optimal : a physical analysis of much simpler structures is used to constrain the optimization process. The obtained designs are based on a flat amorphous silicon layer (to minimize recombination) with a patterned anti-reflective coating made of ITO or ZnO, or a composite ITO/ZnO coating. These latter structures are realistic and present good performances despite very thin active layers.

  9. Minimizing scattering from antireflective surfaces replicated from low-aspect-ratio black silicon

    DEFF Research Database (Denmark)

    Christiansen, Alexander Bruun; Clausen, Jeppe; Mortensen, N. Asger;

    2012-01-01

    The scattering properties of randomly structured antireflective black silicon polymer replica have been investigated. Using a two-step casting process, the structures can be replicated in Ormocomp on areas of up to 3 in. in diameter. Fourier analysis of scanning electron microscopy images of the...... reflectance by a factor of two....

  10. Omnidirectional luminescence enhancement of fluorescent SiC via pseudoperiodic antireflective subwavelength structures

    DEFF Research Database (Denmark)

    Ou, Yiyu; Jokubavicius, Valdas; Yakimova, Rositza;

    2012-01-01

    In the present work, an approach of fabricating pseudoperiodic antireflective subwavelength structures (ARS) on fluorescent SiC by using self-assembled etch mask is demonstrated. By applying the pseudoperiodic (ARS), the average surface reflectance at 6° incidence over the spectral range of 390...

  11. Top-flat and top-patterned cone gratings for mid-infrared antireflective properties

    Science.gov (United States)

    Brückner, Jean-Baptiste; Le Rouzo, Judikaël.; Escoubas, Ludovic; Flory, François; Simon, Jean-Jacques; Berginc, Gérard

    2013-03-01

    Achieving a broadband antireflection property from material surfaces is one of the highest priorities for those who want to improve the efficiency of solar cells or the sensitivity of photo-detectors. To lower the reflectance of a surface, we have decided to study the optical response of a top-flat cone shaped silicon grating, based on previous work exploring pyramid gratings. Through rigorous numerical methods, such as Finite Different Time Domain or Rigorous Coupled-Wave Analysis, we then designed several structures theoretically demonstrating an antireflective character within the middle infrared region. From the opto-geometrical parameters such as period, depth and shape of the pattern determined by numerical analysis, these structures have been fabricated using controlled slope plasma etching processes. Afterwards, optical characterizations of several samples were carried out. The reflectance of the grating in the near and middle infrared domains has been measured by Fourier Transform Infrared spectrometry and a comparison with numerical analysis has been made. As expected, those structures offer a fair antireflective character in the region of interest. Further numerical investigations led to the fact that patterning the top of the cone could enlarge the antireflective domain to the visible region. Thus, as with the simple cone grating, a comparison of the numerical analysis with the experimental measurements is made. Finally, diffracted orders are studied and compared between both structures. Those orders are critical and must be limited as one wants to avoid crosstalk phenomena in imaging systems.

  12. A study of the anti-reflection efficiency of natural nano-arrays of varying sizes

    Energy Technology Data Exchange (ETDEWEB)

    Sun Mingxia; Liang Aiping [Key Laboratory of the Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing (China); Zheng Yongmei [School of Chemistry and Environment, Beihang University, 100191 Beijing (China); Watson, Gregory S; Watson, Jolanta A, E-mail: liangap@ioz.ac.cn, E-mail: zhengym@buaa.edu.cn [School of Pharmacy and Molecular Sciences, James Cook University, Townsville, 4811 QLD (Australia)

    2011-06-15

    The dependence of optical reflectivity and wettability on the surface topography of 32 species of cicada wing membranes has been investigated using UV-visible spectrophotometry, contact angle measurements and environmental scanning electron microscopy. The nanoscale hexagonally close packed protrusions have been shown to exhibit an anti-reflection and in some cases an anti-wetting function. The parameters of the structures were measured to be 77-148 nm in diameter, 44-117 nm in spacing and 159-481 nm in height. The transmittance spectrum and static contact angles were measured. At a wavelength range of 500-2500 nm, only minor differences in the anti-reflection performance were observed for each cicada species ascribed to the mechanism of impedance matching between cuticle and air. The transmittance properties of cicada wings were altered successfully through the scanning probe microscope-based manipulation by reducing the protrusion height via the contact mode. A near linear dependence was found between a decrease in protuberance height and a resulting increase in reflectance intensity. A diversity of wettability was observed with contact angles varying from 56.5{sup 0} to 146.0{sup 0}. Both effects of anti-reflection and wettability are dependent on the height of protrusions. The anti-reflection is insensitive when the wavelength is larger than the lateral feature size of the nanostructure. The stronger hydrophobic properties are generally associated with a larger diameter, closer spacing and greater height of protrusions when the wing membrane is intact.

  13. Black metal thin films by deposition on dielectric antireflective moth-eye nanostructures

    DEFF Research Database (Denmark)

    Christiansen, Alexander Bruun; Caringal, Gideon Peter; Clausen, Jeppe Sandvik; Grajower, Meir; Taha, Hesham; Levy, Uriel; Mortensen, N. Asger; Kristensen, Anders

    2015-01-01

    Although metals are commonly shiny and highly reflective, we here show that thin metal films appear black when deposited on a dielectric with antireflective moth-eye nanostructures. The nanostructures were tapered and close-packed, with heights in the range 300-600 nm, and a lateral, spatial...

  14. Use of antireflection layers to avoid ghost plating on Ni/Cu plated crystalline silicon solar cells

    Science.gov (United States)

    Jeong, Myeong Sang; Choi, Sung Jin; Chang, Hyo Sik; In Lee, Jeong; Kang, Min Gu; Kim, Donghwan; Song, Hee-eun

    2016-03-01

    Screen printing is a method commonly used for making electrodes for crystalline silicon solar cells. Although the screen-printing method is fast and easy, screen-printed electrodes have a porous structure, high contact resistance, and low aspect ratio. On the other hand, plated electrodes have low contact resistance and narrow electrode width. Therefore, the plating method could be substituted for the screen-printing method in crystalline silicon solar cells. During the plating process, ghost plating can appear at the surface when the quality of the passivation layer is poor, causing an increase in the recombination rate. In this paper, light-induced plating was applied to the fabrication of electrodes, and various passivation layers were investigated to remove ghost plating in crystalline silicon solar cells. These included, (1) SiNx deposited by plasma-enhanced chemical vapor deposition (PECVD), (2) a double SiNx layer formed by PECVD, (3) a double layer with thermal silicon oxide and SiNx deposited by PECVD, and (4) a double layer comprising SiNx and SiOx formed by PECVD. For the plated solar cells, a laser was used to remove various antireflection coating (ARC) layers and phosphoric acid was spin-coated onto the doped silicon wafer prior to laser ablation. Also, a screen-printed solar cell was fabricated to compare plated solar cells with screen-printed solar cells. As a result, we found that a thermal SiO2/PECVD SiNx layer showed the lowest pinhole density and its wet vapor transmission rate was characterized. The solar cell with the thermal SiO2/PECVD SiNx layer showed the lowest J02 value, as well as improved Voc and Jsc.

  15. Sol-gel optical coatings for lasers, 2

    International Nuclear Information System (INIS)

    There are three basic types of antireflective (AR) coatings. The first is a single-layer coating in which the coating index is equal to the square root of the index of the substrate, assuming air is the external medium. The second type is a system of two or more layers of different indexes. The third type is a graded-index system, where the index is uniformly and continuously graded from the substrate to the external medium. Low reflection ranges from narrow for the single-layer to broad for the graded-layer and multilayered with a large number of layers. Four types of sol-gel AR coatings have been developed at CEL-V. They are based on single-layer or multilayer designs. They consist mainly of amorphous silica in the polymeric and/or colloidal state, combined in certain cases with other metallic oxides, binders, fillers, hydrophobic and lubricating agents, and adhesion promoters. These antireflective sol-gel-derived optical coatings have been prepared and tested for the proposed French megajoule neodymium-glass laser

  16. Improvement and characterization of high-reflective and anti-reflective nanostructured mirrors by ion beam assisted deposition for 944 nm high power diode laser

    Science.gov (United States)

    Ghadimi-Mahani, A.; Farsad, E.; Goodarzi, A.; Tahamtan, S.; Abbasi, S. P.; Zabihi, M. S.

    2015-11-01

    Single-layer and multi-layer coatings were applied on the surface of diode laser facets as mirrors. This thin film mirrors were designed, deposited, optimized and characterized. The effects of mirrors on facet passivation and optical properties of InGaAs/AlGaAs/GaAs diode lasers were investigated. High-Reflective (HR) and Anti-Reflective (AR) mirrors comprising of four double-layers of Al2O3/Si and a single layer of Al2O3, respectively, were designed and optimized by Macleod software for 944 nm diode lasers. Optimization of Argon flow rate was studied through Alumina thin film deposition by Ion Beam Assisted Deposition (IBAD) for mirror improvement. The nanostructured HR and AR mirrors were deposited on the front and back facet of the laser respectively, by IBAD system under optimum condition. Atomic Force Microscope (AFM), Vis-IR Spectrophotometer, Field Emission Scanning Electron Microscopy (FESEM) and laser characterization Test (P-I) were used to characterize various properties of mirrors and lasers. AFM images show mirror's root mean square roughness is nearly 1 nm. The Spectrophotometer results of the front facet transmission and the back facet reflection are in good agreement with the simulation results. Optical output power (P) versus driving current (I) characteristics, measured before and after coating the facet, revealed a significant output power enhancement due to optimized AR and HR optical coatings on facets.

  17. Efficient light incoupling into silicon thin-film solar cells by anti-reflecting MgO/high-compact-AZO with air-side textured glass

    International Nuclear Information System (INIS)

    Light incoupling effects have been enhanced at front interfaces of silicon (Si) thin-film solar cells. Firstly, a MgO thin film was introduced at glass substrate/Al-doped ZnO (AZO) interface for anti-reflection effect. We additionally found that the surface morphology of AZO films grown on MgO film after texture-etching is dependent on the compactness of AZO. For high-compact AZO films, the texture-etched MgO/AZO double layer exhibited significantly enhanced light-scattering capability. Secondly, we made textured surfaces at air/glass interface through simple plasma-etching without sacrificial layers or masks by optimizing the etching pressure. The additional air-side texture contributed to further improvement of total light scattering from the MgO/AZO-coated glass substrate. Fabricated microcrystalline Si thin-film solar cells employing the MgO coated glass with air-side surface texture showed decreased cell reflectance and increased quantum efficiency. The Jsc increased from 21.7 to 26.5 mA cm−2 and final efficiency of 9.49% was achieved. Based on our experimental results, the suggested structure, the MgO coating on glass substrate of which air-side surface is texture-etched, can offer a promising approach to improve the light incoupling and efficiency of Si thin-film solar cells. (paper)

  18. The influence of process parameters and coating properties of double glazing coated with transparent conducting oxides on the efficiency of solar-thermal flat-plate collectors

    International Nuclear Information System (INIS)

    In order to increase the performance of a solar-thermal flat-plate collector, we insert a double glazing with low-emitting (low-e) coating on the inner glass pane. The low-e coating system is based on sputter deposited aluminum-doped zinc oxide (AZO) and additional antireflective (AR) coatings. In this paper, we analyze the optical and electronic AZO film properties in dependence of the process parameters such as substrate temperature, argon pressure, direct current (DC) power, and target doping concentration. Emphasis is placed on the influence of these coating properties and the application of AR coatings on the efficiency of the double-glazed collector. Simulations of the collector efficiency with our collector model are presented. - Highlights: ► We apply a ZnO:Al coating to a double-glazed solar-thermal flat-plate collector. ► We analyze the influence of the deposition parameters on the collector efficiency. ► The influence of the substrate temperature, argon pressure, and DC power is low. ► The doping concentration and antireflective coatings have a strong influence. ► The collector efficiency is up to 45% higher compared to a single-glazed collector

  19. Y{sub 2}O{sub 3}: Eu{sup 3+}, Tb{sup 3+} spherical particles based anti-reflection and wavelength conversion bi-functional films: Synthesis and application to solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Hui [School of Physics, Northwest University, Xi’an 710069 (China); National Photoelectric Technology and Functional Materials & Application of Science and Technology International Cooperation Base, Northwest University, Xi’an 710069 (China); Ji, Ruonan [School of Physics, Northwest University, Xi’an 710069 (China); Hu, Xiaoyun, E-mail: hxy3275@nwu.edu.cn [School of Physics, Northwest University, Xi’an 710069 (China); National Photoelectric Technology and Functional Materials & Application of Science and Technology International Cooperation Base, Northwest University, Xi’an 710069 (China); Han, Linzi; Hao, Yuanyuan; Sun, Qian [School of Physics, Northwest University, Xi’an 710069 (China); Zhang, Dekai [School of Physics, Northwest University, Xi’an 710069 (China); National Photoelectric Technology and Functional Materials & Application of Science and Technology International Cooperation Base, Northwest University, Xi’an 710069 (China); Fan, Jun [School of Chemical Engineering, Northwest University, Xi’an 710069 (China); Bai, Jintao [School of Physics, Northwest University, Xi’an 710069 (China); National Photoelectric Technology and Functional Materials & Application of Science and Technology International Cooperation Base, Northwest University, Xi’an 710069 (China); and others

    2015-04-25

    Highlights: • Eu{sup 3+} and Tb{sup 3+} co-doped Y{sub 2}O{sub 3} particles were successfully prepared. The as prepared particles can convert UV region photos to visible photons between 460 nm and 640 nm, which just matched the spectral response of most solar cells. • Y{sub 2}O{sub 3} is not only a good photoluminescence host material, but also it has high corrosion resistivity, thermal stability, and transparency from violet to infrared light. Cooperated with SiO{sub 2} sols, it could realize a better anti-reflection property. • As a proof-of-concept application, the as prepared bi-functional films could effectively improve the photoelectric conversion efficiency by 0.23% compared to pure SiO{sub 2} AR coating film and 0.55% compared to glass. - Abstract: In this study, Eu{sup 3+} and Tb{sup 3+} co-doped Y{sub 2}O{sub 3} particles were prepared via the simple, cost-effective urea homogeneous precipitation method without additives. The chosen particles were added in the SiO{sub 2} sols to get anti-reflection (AR) and wavelength conversion bi-functional films. Careful investigations were carried out to find the optimum preparation conditions and proper morphology. SEM images showed that the particle sizes reduced as metal ion/urea ratio decreased. Additionally, the extracted particles turned from sphere to lamellar type when the deionized water, which was used as solvent, reduced to a certain extent. The mechanisms of the morphology formation and diversification were proposed as well. The as prepared materials can convert UV region photos to visible photons between 460 nm and 640 nm, which just matched the spectral response of most solar cells. The spherical sample showed better luminescence performance than the one with lamellar morphology. In addition, the optical transmittance spectra indicated that the films adding spherical particles had better anti-reflective performance, and the best adding amount was 0.08 g. Finally, As a proof-of-concept application

  20. Nanostructured networks of single wall carbon nanotubes for highly transparent, conductive, and anti-reflective flexible electrodes

    OpenAIRE

    Boulanger, Nicolas; Barbero, David

    2013-01-01

    Highly transparent, anti-reflective, flexible, and conductive electrodes are produced by nanopatterning of a polymer composite made of single wall carbon nanotubes (SWNTs). The formation of nanostructures creates interconnected nanotubes and vertically aligned SWNT networks which greatly improves charge transport compared to a traditionally mixed composite. These electrodes moreover possess high transparency (98% at 550 nm) and good anti-reflective properties. The use of low nanotube loadings...

  1. Transparent conductive coatings

    Science.gov (United States)

    Ashok, S.

    1983-01-01

    Thin film transparent conductors are discussed. Materials with electrical conductivity and optical transparency are highly desirable in many optoelectronic applications including photovoltaics. Certain binary oxide semiconductors such as tin oxide (SnO2) and indium oxide (In2O3) offer much better performance tradeoff in optoelectronics as well as better mechanical and chemical stability than thin semitransparent films. These thin-film transparent conductors (TC) are essentially wide-bandgap degenerate semiconductors - invariably n-type - and hence are transparent to sub-bandgap (visible) radiation while affording high electrical conductivity due to the large free electron concentration. The principal performance characteristics of TC's are, of course, electrical conductivity and optical transmission. The TC's have a refractive index of around 2.0 and hence act as very efficient antireflection coatings. For using TC's in surface barrier solar cells, the photovoltaic barrier is of utmost importance and so the work function or electron affinity of the TC is also a very important material parameter. Fabrication processes are discussed.

  2. Fabrication of nano-structure anti-reflective lens using platinum nanoparticles in injection moulding

    International Nuclear Information System (INIS)

    We provide a lens mould to attain an anti-reflection sub-wavelength structure (SWS) for plastic replica in the injection moulding process. To obtain the SWS on the lens mould, platinum nanoparticles formed by decomposition of a platinum oxide were employed. The fabricated platinum nanoparticles were estimated to be 90 nm in diameter, on average, and the dispersion of the particle diameter was evaluated to be ±20 nm. Through nanostructure replication by injection moulding, antireflection of less than 0.5% was achieved, and transmittance increased over 98%. In addition, a high-replication durability of over 10 000 times was attained. The variation of the minimum reflection ratio was evaluated to be 0.38% ± 0.04%. The usefulness of the proposed SWS mould for mass-production was confirmed, as it allows for high durability and SWS formation on the lens surface. (paper)

  3. Bioinspired periodic pinecone-shaped Si subwavelength nanostructures for broadband and omnidirectional antireflective surface.

    Science.gov (United States)

    Leem, Jung Woo; Yu, Jae Su

    2012-10-01

    We reported the bioinspired periodic pinecone-shaped silicon (Si) subwavelength nanostructures, which were fabricated by laser interference lithography and inductively coupled plasma etching using thermally dewetted gold (Au) nanoparticles in SiCl4 plasma, on Si substrates for broadband and wide-angle antireflective surface. For the fabricated pinecone-like Si subwavelength nanostructures, antireflection characteristics and wetting behaviors were investigated. The pinecone-shaped Si subwavelength nanostructure with a period of 320 nm for 7 nm of Au film exhibited a relatively low solar weighted reflectance value of 3.5% over a wide wavelength range of 300-1030 nm, maintaining the reflectance values of < 9.9% at a wavelength of 550 nm up to a high incident angle of theta(i) = 70 degrees for non-polarized light. This structure also showed a hydrophobic surface with a water contact angle of theta(c) approximately 102 degrees. PMID:23421159

  4. Wide angle and broadband antireflection properties for a silicon nanotip array

    Science.gov (United States)

    Huang, Yi-Fan; Jen, Yi-Jun; Chen, Kuei-Hsien; Chen, Li-Chyong

    2008-08-01

    Biomimetic structures provided important clues for nano-synthesis in pursuit of enhanced performances. Here, we report a wide angle and broadband antireflection is observed on a 6-inch silicon nanotip array (SiNTs) substrate fabricated using a single step electron cyclotron resonance plasma etching technique. This subwavelength structure consists of the SiNTs with apex and bottom diameter of ~5 nm and ~200 nm, respectively, length of ~1600 nm and density of 109/cm2. This aperiodic array of SiNTs with geometry designed in the sub-wavelength level to demonstrate a low hemispherical reflectance of Dobrowolski. This near ideal antireflection property suggests enhanced performances in renewable energy, and electro-optical devices in defense applications.

  5. Geometric dependence of antireflective nanocone arrays towards ultrathin crystalline silicon solar cells

    International Nuclear Information System (INIS)

    The antireflective characteristics of Si nanocone (NC) arrays were estimated using a theory devised for an inhomogeneous antireflection layer, and further verified by the Fourier modal method (FMM). Considering a better impedance matching from air to Si, a minimum depth of 400 nm is essentially required. Although Si NC arrays have usually been suggested to be at a base diameter of ∼300 nm for infinitely thick Si wafers, as wafers become thinner than 50 μm, the optimal base diameter of the NCs is suggested to be ∼500 nm so as to excite more resonant modes. Our simulation work indicates that geometrical parameters such as the top diameter and filling ratio of the NCs are much more sensitive in terms of optimizing the optical performance on ultrathin (∼5 μm) wafers, suggesting the need for strict control of the surface morphology in the nanostructure fabrication process. (paper)

  6. Thermal Advantages for Solar Heating Systems with a Glass Cover with Antireflection Surfaces

    DEFF Research Database (Denmark)

    Furbo, Simon; Shah, Louise Jivan

    2003-01-01

    surfaces was determined for different solar heating systems. Three systems were investigated: solar domestic hot water systems, solar heating systems for combined space heating demand and domestic hot water supply, and large solar heating plants. The yearly thermal performance of the systems was calculated...... by detailed simulation models with collectors with a normal glass cover and with a glass cover with antireflection surfaces. The calculations were carried out for different solar fractions and temperature levels of the solar heating systems. These parameters influence greatly the thermal performance......Investigations elucidate how a glass cover with antireflection surfaces can improve the efficiency of a solar collector and the thermal performance of solar heating systems. The transmittances for two glass covers for a flat-plate solar collector were measured for different incidence angles. The...

  7. Preparation and performance of broadband antireflective sub-wavelength structures on Ge substrate

    Institute of Scientific and Technical Information of China (English)

    沈祥伟; 刘正堂; 李阳平; 卢红成; 徐启远; 刘文婷

    2009-01-01

    Sub-wavelength structures(SWS) were prepared on Ge substrates through photolithography and reactive ion etching(RIE) technology for broadband antireflective purposes in the long wave infrared(LWIR) waveband of 8-12 μm.Topography of the etched patterns was observed using high resolution optical microscope and atomic force microscope(AFM).Infrared transmission performance of the SWS was investigated by Fourier transform infrared(FTIR) spectrometer.Results show that the etched patterns were of high uniformity ...

  8. Fabrication of CuO-based antireflection structures using self-arranged submicron SiO2 spheres for thermoelectric solar generation

    Science.gov (United States)

    Kondo, Tasuku; Mizoshiri, Mizue; Mikami, Masashi; Itou, Yoshitaka; Sakurai, Junpei; Hata, Seiichi

    2016-06-01

    We fabricated antireflection structures (ARSs) on the hot side of a thermoelectric generator (TEG) to absorb near-infrared (NIR) solar light with low reflective energy loss. First, the ARSs, composed of a CuO thin-film coated hemisphere array were designed using rigorous coupled wave analysis. Reflective loss was reduced to 6.7% at a grating period of 200 nm, as determined by simulation. Then, the ARSs were fabricated on a glass substrate using self-arranged submicron SiO2 spheres, following the coating of a CuO thin film. Finally, the effect of the ARSs on NIR solar light generation was investigated by evaluating the generation properties of the TEG with the ARSs on the hot side. In comparison with the TEG with the CuO flat thin film on the hot side, the ARSs increased the temperature difference between the hot and cold sides by approximately 1.4 times. The CuO-based ARSs absorbed NIR solar light effectively.

  9. Both antireflection and superhydrophobicity structures achieved by direct laser interference nanomanufacturing

    Science.gov (United States)

    Wang, Dapeng; Wang, Zuobin; Zhang, Ziang; Yue, Yong; Li, Dayou; Qiu, Renxi; Maple, Carsten

    2014-06-01

    Inspired by nature, a number of techniques have been developed to fabricate the bionic structures of lotus leaves and moth eyes in order to realize the extraordinary functions of self-cleaning and antireflection. Compared with the existing technologies, we present a straightforward method to fabricate well-defined micro and nano artificial bio-structures in this work. The proposed method of direct laser interference nanomanufacturing (DLIN) takes a significant advantage of high efficiency as only a single technological procedure is needed without pretreatment, mask, and pattern transfer processes. Meanwhile, the corresponding structures show both antireflection and superhydrophobicity properties simultaneously. The developed four-beam nanosecond laser interference system configuring the TE-TE-TE-TE and TE-TE-TE-TM polarization modes was set up to generate periodic micro cone and hole structures with a huge number of nano features on the surface. The theoretical and experimental results have shown that the periodic microcone structure exhibits excellent properties with both a high contact angle (CA = 156.3°) and low omnidirectional reflectance (5.9-15.4%). Thus, DLIN is a novel and promising method suitable for mass production of self-cleaning and antireflection surface structures.

  10. Both antireflection and superhydrophobicity structures achieved by direct laser interference nanomanufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dapeng; Wang, Zuobin, E-mail: wangz@cust.edu.cn; Maple, Carsten [JR3CN and CNM, Changchun University of Science and Technology, Changchun, 130022 (China); JR3CN and IRAC, University of Bedfordshire, Luton, Bedfordshire LU1 3JU (United Kingdom); Zhang, Ziang [JR3CN and CNM, Changchun University of Science and Technology, Changchun, 130022 (China); Yue, Yong [JR3CN and CNM, Changchun University of Science and Technology, Changchun, 130022 (China); JR3CN and IRAC, University of Bedfordshire, Luton, Bedfordshire LU1 3JU (United Kingdom); DCSSE, Xi' an Jiaotong-Liverpool University, Suzhou, 215123 (China); Li, Dayou; Qiu, Renxi [JR3CN and IRAC, University of Bedfordshire, Luton, Bedfordshire LU1 3JU (United Kingdom)

    2014-06-21

    Inspired by nature, a number of techniques have been developed to fabricate the bionic structures of lotus leaves and moth eyes in order to realize the extraordinary functions of self-cleaning and antireflection. Compared with the existing technologies, we present a straightforward method to fabricate well-defined micro and nano artificial bio-structures in this work. The proposed method of direct laser interference nanomanufacturing (DLIN) takes a significant advantage of high efficiency as only a single technological procedure is needed without pretreatment, mask, and pattern transfer processes. Meanwhile, the corresponding structures show both antireflection and superhydrophobicity properties simultaneously. The developed four-beam nanosecond laser interference system configuring the TE-TE-TE-TE and TE-TE-TE-TM polarization modes was set up to generate periodic micro cone and hole structures with a huge number of nano features on the surface. The theoretical and experimental results have shown that the periodic microcone structure exhibits excellent properties with both a high contact angle (CA = 156.3°) and low omnidirectional reflectance (5.9–15.4%). Thus, DLIN is a novel and promising method suitable for mass production of self-cleaning and antireflection surface structures.

  11. Nanoporosity-induced superhydrophobicity and large antireflection in InSb

    Science.gov (United States)

    Datta, Debi Prasad; Som, Tapobrata

    2016-05-01

    A porous nanostructure evolves in InSb due to keV ion implantation which leads to superhydrophobic and large antireflective property, indicating a single-step facile fabrication to introduce both functionalities. In particular, it is observed that the contact angle of a water droplet on the nanoporous InSb surface exceeds 150°, revealing the transition to a superhydrophobic surface. Correlation between the contact angle and the porous nanostructures is qualitatively understood in light of the Cassie-Baxter model. It is found that a decrease in the fraction of solid surface wetted by the water droplet and a corresponding increase in the air-water interface fraction lead to the enhancement in the hydrophobicity. We further observe that the large broadband antireflection (in the range of 200-800 nm) is also correlated to the nanoporous structure, arising out of a large reduction in the refractive index due to its increasing porosity. Such a surface with the combination of superhydrophobicity and large antireflection can be very useful for applications of InSb nanostructures in electronic, photonic devices, or infrared detectors.

  12. Antireflective sub-wavelength structures on fused silica via self-assembly of silica

    International Nuclear Information System (INIS)

    Antireflective sub-wavelength structures with high laser-induced damage threshold on fused silica are fabricated using a self-assembly technique, in which a porous yttrium oxide film is deposited as a mask followed by alkaline etching. By controlling the etching time, several sub-wavelength structures with different height, density and diameter have been made. The best reflectance is less than 2.87% for wavelengths from 300 to 1000 nm after 1.5 h etching. The laser-induced damage threshold of the etched glass measured by a 10 ns Nd:YAG laser at a wavelength of 532 nm was as high as 30 J/cm2 compared to 16 J/cm2 of blank glass. The specular reflectance of structures matches the theoretical simulation using a thin-film multilayer model, and the results reveal that the shape of the structures is similar to the calculated parabolic shape. Achieving antireflective sub-wavelength structures on fused silica paves the way for applications in laser systems. - Highlights: • Antireflective structures on fused silica are grown using a self-assembly technique. • The properties of structures with different etching time were studied. • The laser-induced damage threshold of glass was enhanced after etching. • The reflection matches the theoretical simulation using a thin-film multilayer model

  13. Both antireflection and superhydrophobicity structures achieved by direct laser interference nanomanufacturing

    International Nuclear Information System (INIS)

    Inspired by nature, a number of techniques have been developed to fabricate the bionic structures of lotus leaves and moth eyes in order to realize the extraordinary functions of self-cleaning and antireflection. Compared with the existing technologies, we present a straightforward method to fabricate well-defined micro and nano artificial bio-structures in this work. The proposed method of direct laser interference nanomanufacturing (DLIN) takes a significant advantage of high efficiency as only a single technological procedure is needed without pretreatment, mask, and pattern transfer processes. Meanwhile, the corresponding structures show both antireflection and superhydrophobicity properties simultaneously. The developed four-beam nanosecond laser interference system configuring the TE-TE-TE-TE and TE-TE-TE-TM polarization modes was set up to generate periodic micro cone and hole structures with a huge number of nano features on the surface. The theoretical and experimental results have shown that the periodic microcone structure exhibits excellent properties with both a high contact angle (CA = 156.3°) and low omnidirectional reflectance (5.9–15.4%). Thus, DLIN is a novel and promising method suitable for mass production of self-cleaning and antireflection surface structures.

  14. Broadband High-Performance Infrared Antireflection Nanowires Facilely Grown on Ultrafast Laser Structured Cu Surface.

    Science.gov (United States)

    Fan, Peixun; Bai, Benfeng; Long, Jiangyou; Jiang, Dafa; Jin, Guofan; Zhang, Hongjun; Zhong, Minlin

    2015-09-01

    Infrared antireflection is an essential issue in many fields such as thermal imaging, sensors, thermoelectrics, and stealth. However, a limited antireflection capability, narrow effective band, and complexity as well as high cost in implementation represent the main unconquered problems, especially on metal surfaces. By introducing precursor micro/nano structures via ultrafast laser beforehand, we present a novel approach for facile and uniform growth of high-quality oxide semiconductor nanowires on a Cu surface via thermal oxidation. Through the enhanced optical phonon dissipation of the nanowires, assisted by light trapping in the micro structures, ultralow total reflectance of 0.6% is achieved at the infrared wavelength around 17 μm and keeps steadily below 3% over a broad band of 14-18 μm. The precursor structures and the nanowires can be flexibly tuned by controlling the laser processing procedure to achieve desired antireflection performance. The presented approach possesses the advantages of material simplicity, structure reconfigurability, and cost-effectiveness for mass production. It opens a new path to realize unique functions by integrating semiconductor nanowires onto metal surface structures. PMID:26280305

  15. High power laser antireflection subwavelength grating on fused silica by colloidal lithography

    Science.gov (United States)

    Ye, Xin; Huang, Jin; Geng, Feng; Liu, Hongjie; Sun, Laixi; Yan, Lianghong; Jiang, Xiaodong; Wu, Weidong; Zheng, Wanguo

    2016-07-01

    In this study we report on an efficient and simple method to fabricate an antireflection subwavelength grating on a fused silica substrate using two-step reactive ion etching with monolayer polystyrene colloidal crystals as masks. We show that the period and spacing of the obtained subwavelength grating were determined by the initial diameter of polystyrene microspheres and the oxygen ion etching duration. The height of pillar arrays can be adjusted by tuning the second-step fluorine ion etching duration. These parameters are proved to be useful in tailoring the antireflection properties of subwavelength grating using a finite-difference time-domain (FDTD) method and effective medium theory. The subwavelength grating exhibits excellent antireflection properties. The near-field distribution of the SWG which is directly patterned into the substrate material is performed by a 3D-FDTD method. It is found that the near-field distribution is strongly dependent on the periodicity of surface structure, which has the potential to promote the ability of anti-laser-induced damage. For 10 ns pulse duration and 1064 nm wavelength, we experimentally determined their laser induced damage threshold to 32 J cm‑2, which is nearly as high as bulk fused silica with 31.5 J cm‑2.

  16. High-contrast top-emitting organic light-emitting diodes with a Ni/ZnS/CuPc/Ni contrast-enhancing stack and a ZnS anti-reflection layer

    Science.gov (United States)

    Chen, Shufen; Xie, Jun; Yang, Yang; Chen, Chunyan; Huang, Wei

    2010-09-01

    High-contrast top-emitting organic light-emitting diodes are successfully fabricated using a Ni/ZnS/copper-phthalocyanine (CuPc)/Ni contrast-enhancing stack (CES) and a ZnS anti-reflection (AR) layer. The CES and AR layer that are outside the active region reduce the complexity of the device design although their utilization affects the device electrical performance due to morphological deterioration of the device films. After the thickness optimization of the CES and AR coating, high contrast ratios of 139.4 : 1 and 462.3 : 1 are obtained under on-state luminances of 300 and 1000 cd m-2 and an ambient luminance of 140 lux. The reduced reflectance of ambient illumination is mainly due to the anti-reflection ZnS layer and the strong absorption of ambient illumination by the Ni layers, where the CES structure is beneficial for the absorption of ambient illumination by the interfacial reflection of Ni/ZnS and CuPc/Ni.

  17. Thin film coated submicron gratings: theory, design, fabrication and application

    Energy Technology Data Exchange (ETDEWEB)

    Heine, C.

    1996-12-31

    The realization of new applications of submicron grating structures requires efficient theoretical methods and elaborate fabrication techniques. In this work rigorous diffraction theory for one-dimensional gratings has been investigated and optimization techniques, based on methods used in thin film optics, have been developed. Submicron gratings embossed in polycarbonate have been fabricated and characterized. This includes transmission measurements which are in good agreement with theoretical calculations. Designs for a wide range of optical filters, which lead to improved optical and mechanical properties, are presented. This has been demonstrated for broadband antireflection structures for solar energy applications, based on MgF{sub 2}-coated gratings. (author) figs., tabs., refs.

  18. High temperature solar selective coatings

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, Cheryl E

    2014-11-25

    Improved solar collectors (40) comprising glass tubing (42) attached to bellows (44) by airtight seals (56) enclose solar absorber tubes (50) inside an annular evacuated space (54. The exterior surfaces of the solar absorber tubes (50) are coated with improved solar selective coatings {48} which provide higher absorbance, lower emittance and resistance to atmospheric oxidation at elevated temperatures. The coatings are multilayered structures comprising solar absorbent layers (26) applied to the meta surface of the absorber tubes (50), typically stainless steel, topped with antireflective Savers (28) comprising at least two layers 30, 32) of refractory metal or metalloid oxides (such as titania and silica) with substantially differing indices of refraction in adjacent layers. Optionally, at least one layer of a noble metal such as platinum can be included between some of the layers. The absorbent layers cars include cermet materials comprising particles of metal compounds is a matrix, which can contain oxides of refractory metals or metalloids such as silicon. Reflective layers within the coating layers can comprise refractory metal silicides and related compounds characterized by the formulas TiSi. Ti.sub.3SiC.sub.2, TiAlSi, TiAN and similar compounds for Zr and Hf. The titania can be characterized by the formulas TiO.sub.2, Ti.sub.3O.sub.5. TiOx or TiO.sub.xN.sub.1-x with x 0 to 1. The silica can be at least one of SiO.sub.2, SiO.sub.2x or SiO.sub.2xN.sub.1-x with x=0 to 1.

  19. Surface passivation and antireflectance performances for atomic-layer-deposited Al2O3 films

    International Nuclear Information System (INIS)

    Al2O3 films were deposited on single crystalline silicon wafers by atomic layer deposition. Both passivation and antireflectance performances are studied in detail. 30 nm Al2O3 passivated n-type and p-type Si shows a maximum effective minority carrier lifetime (τeff) of ∼5.2 ms and ∼4.7 ms, corresponding to a low surface recombination velocity of ∼3.8 cm s−1 and ∼4.2 cm s−1, respectively. By drawing a contour map of post-deposition annealing (PDA) temperature, PDA time and τeff, a wide PDA window is obtained for obtaining good passivation performances. The excellent passivation performances are related to the large, negative fixed charge density within Al2O3 films and the formation of interfacial SiO2 layer at the Al2O3/Si interface. Antireflectance performances are also studied in detail for Al2O3 and Al2O3/SiNx double-layer on textured Si. For obtaining a low average reflectance between 2.6% and 3%, a wide film-thickness window of ∼30 nm for Al2O3 and SiNx layer is observed for Al2O3/SiNx double-layer on textured Si. Our results indicate that Al2O3 films have excellent surface passivation and antireflectance performances with a wide processing window, which is favorable for c-Si solar cell applications. (paper)

  20. Antireflective grassy surface on glass substrates with self-masked dry etching

    Science.gov (United States)

    Song, Young Min; Park, Gyeong Cheol; Kang, Eun Kyu; Yeo, Chan Il; Lee, Yong Tak

    2013-12-01

    Although recently developed bio-inspired nanostructures exhibit superior optic performance, their practical applications are limited due to cost issues. We present highly transparent glasses with grassy surface fabricated with self-masked dry etch process. Simultaneously generated nanoclusters during reactive ion etch process with simple gas mixture (i.e., CF4/O2) enables lithography-free, one-step nanostructure fabrication. The resulting grassy surfaces, composed of tapered subwavelength structures, exhibit antireflective (AR) properties in 300 to 1,800-nm wavelength ranges as well as improved hydrophilicity for antifogging. Rigorous coupled-wave analysis calculation provides design guidelines for AR surface on glass substrates.

  1. Broadband antireflective silicon carbide surface produced by cost-effective method

    DEFF Research Database (Denmark)

    Argyraki, Aikaterini; Ou, Yiyu; Ou, Haiyan

    2013-01-01

    A cost-effective method for fabricating antireflective subwavelength structures on silicon carbide is demonstrated. The nanopatterning is performed in a 2-step process: aluminum deposition and reactive ion etching. The effect, of the deposited aluminum film thickness and the reactive ion etching...... conditions, on the average surface reflectance and nanostructure landscape have been investigated systematically. The average reflectance of silicon carbide surface is significantly suppressed from 25.4% to 0.05%, under the optimal experimental conditions, in the wavelength range of 390-784 nm. The presence...

  2. Absorbing Backside Anti-reflecting Layers for high contrast imaging in fluid cells

    CERN Document Server

    Ausserré, Dominique; Amra, Claude; Zerrad, Myriam

    2014-01-01

    The single Anti-Reflecting (AR) layer is a classical problem in optics. When all materials are pure dielectrics, the solution is the so-called lambda/4 layer. Here we examine the case of absorbing layers between non absorbing media. We find a solution for any layer absorption coefficient provided that the light goes from the higher towards the lower index medium, which characterizes backside layers. We describe these AR absorbing (ARA) layers through generalized index and thickness conditions. They are most often ultrathin, and have important applications for high contrast imaging in fluid cells.

  3. Antireflective structure imprinted on the surface of optical glass by SiC mold

    International Nuclear Information System (INIS)

    An antireflective structure with two-dimensional 300-nm periodicity was fabricated on a phosphate glass surface using an imprinting process with a SiC mold. The optimized structure designed using RCWA calculation was a convex circular cone sharing the ridge line of adjacent cones. The SiC mold was fabricated using electron beam drawing and subsequent reactive ion etching with CHF3 and O2 gases. The glass' surface reflectance was estimated as 0.2% at 530 nm wavelength, which was approximately 1/20 that of the optically polished surface.

  4. Antireflective structure imprinted on the surface of optical glass by SiC mold

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Kazuhiro; Umetani, Makoto; Tamura, Takamasa; Tanaka, Yasuhiro [AVC Devices Development Center, Panasonic AVC Networks Company, Panasonic Corporation, 1006 Kadoma, Kadoma City, Osaka 571-8501 (Japan); Kasa, Haruya [Photonics Research Institute, National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan); Nishii, Junji [Photonics Research Institute, National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan)], E-mail: junji.nishii@aist.go.jp

    2009-01-15

    An antireflective structure with two-dimensional 300-nm periodicity was fabricated on a phosphate glass surface using an imprinting process with a SiC mold. The optimized structure designed using RCWA calculation was a convex circular cone sharing the ridge line of adjacent cones. The SiC mold was fabricated using electron beam drawing and subsequent reactive ion etching with CHF{sub 3} and O{sub 2} gases. The glass' surface reflectance was estimated as 0.2% at 530 nm wavelength, which was approximately 1/20 that of the optically polished surface.

  5. The preparation and properties of Y2O3/AlN anti-reflection films on chemical vapor deposition diamond

    International Nuclear Information System (INIS)

    Yttrium oxide (Y2O3) films have successfully been applied as anti-reflection (AR) and anti-oxidation films for diamond. For significant adhesion improvement between Y2O3 coating and diamond, aluminum nitride (AlN) as an interlayer is introduced. Y2O3 and AlN films were prepared by RF magnetron sputtering of Y2O3 ceramic target in Ar atmosphere and pure Al metal target in Ar + N2 atmosphere, respectively. The Y2O3 and AlN films were studied by X-ray diffraction, X-ray photoelectron spectroscopy, Atomic force microscopy and Spectroscopic ellipsometry. Adherent Y2O3/AlN films on high optical quality chemical vapor deposition diamond with optimum thicknesses for infrared transmission enhancement in 8–10 μm were obtained by a Fourier transform infrared spectrometer. More than 28% increase in maximum transmission was observed for Y2O3/AlN//Diamond//AlN/Y2O3. Comparing between the designed and experimental AR effects for Y2O3/AlN film in 8–10 μm wavebands, experimental average AR effects are smaller for the absorption and scattering loss. AR effects for the Y2O3/AlN films on CVD diamond are proved to be excellent.

  6. 3D-Printed Broadband Dielectric Tube Terahertz Waveguide with Anti-Reflection Structure

    Science.gov (United States)

    Vogt, Dominik Walter; Leonhardt, Rainer

    2016-07-01

    We demonstrate broadband, low loss, and close-to-zero dispersion guidance of terahertz (THz) radiation in a dielectric tube with an anti-reflection structure (AR-tube waveguide) in the frequency range from 0.2 to 1.0 THz. The anti-reflection structure (ARS) consists of close-packed cones in a hexagonal lattice arranged on the outer surface of the tube cladding. The feature size of the ARS is in the order of the wavelength between 0.2 and 1.0 THz. The waveguides are fabricated with the versatile and cost efficient 3D-printing method. Terahertz time-domain spectroscopy (THz-TDS) measurements as well as 3D finite-difference time-domain simulations (FDTD) are performed to extensively characterize the AR-tube waveguides. Spectrograms, attenuation spectra, effective phase refractive indices, and the group-velocity dispersion parameters β 2 of the AR-tube waveguides are presented. Both the experimental and numerical results confirm the extended bandwidth and smaller group-velocity dispersion of the AR-tube waveguide compared to a low loss plain dielectric tube THz waveguide. The AR-tube waveguide prototypes show an attenuation spectrum close to the theoretical limit given by the infinite cladding tube waveguide.

  7. Highly Efficient Flexible Perovskite Solar Cells with Antireflection and Self-Cleaning Nanostructures.

    Science.gov (United States)

    Tavakoli, Mohammad Mahdi; Tsui, Kwong-Hoi; Zhang, Qianpeng; He, Jin; Yao, Yan; Li, Dongdong; Fan, Zhiyong

    2015-10-27

    Flexible thin film solar cells have attracted a great deal of attention as mobile power sources and key components for building-integrated photovoltaics, due to their light weight and flexible features in addition to compatibility with low-cost roll-to-roll fabrication processes. Among many thin film materials, organometallic perovskite materials are emerging as highly promising candidates for high efficiency thin film photovoltaics; however, the performance, scalability, and reliability of the flexible perovskite solar cells still have large room to improve. Herein, we report highly efficient, flexible perovskite solar cells fabricated on ultrathin flexible glasses. In such a device structure, the flexible glass substrate is highly transparent and robust, with low thermal expansion coefficient, and perovskite thin film was deposited with a thermal evaporation method that showed large-scale uniformity. In addition, a nanocone array antireflection film was attached to the front side of the glass substrate in order to improve the optical transmittance and to achieve a water-repelling effect at the same time. It was found that the fabricated solar cells have reasonable bendability, with 96% of the initial value remaining after 200 bending cycles, and the power conversion efficiency was improved from 12.06 to 13.14% by using the antireflection film, which also demonstrated excellent superhydrophobicity. PMID:26284607

  8. Investigation of durability of optical coatings in highly purified tritium gas

    International Nuclear Information System (INIS)

    Anti-reflection coated windows are part of Raman spectroscopy systems for tritium analytics in the KATRIN experiment and fusion-related applications. Damages of such windows were observed after three months of expo-sure to highly purified tritium gas in the LOOPINO facility. In this work, the origin of the damages was investigated, identified and eliminated. Coating samples manufactured by various physical vapor deposition methods have been tested for durability by exposure to pure tritium gas and subsequent visual inspection. Electron beam deposited coatings showed indications for damage after 17 days of tritium exposure in contrast to samples manufactured by ion assisted deposition or sputtering. An improved coating layout of the sample cell is presented for reliable long-term monitoring of tritium gas using Raman spectroscopy. (authors)

  9. Investigation of the neutral-solution etch process for refractive SOE antireflective surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Maish, A.B.

    1991-01-01

    Antireflection of optically clear glass used in photovoltaic concentrator refractive secondary optical elements (SOE's) was investigated using the neutral-solution etch process developed by Schott Glass. Test coupons and SOE's made from barium zinc glass, which does not solarize under ultraviolet exposure, were successfully etched at the center point process variable conditions of 87{degrees}C and 24 hours. Reflectance of the plano-plano dropped from 7.7% to 0.8%, with a corresponding increase in transmission from 91.7% to 98.5%. The etching process uses non-hydrofluoric, relatively non-toxic chemicals in a low-cost process well suited for use by photovoltaic system manufacturers during production. 10 refs., 4 figs., 1 tab.

  10. High refractive index composite for broadband antireflection in terahertz frequency range

    Science.gov (United States)

    Wang, Xuecheng; Li, Yunzhou; Cai, Bin; Zhu, YiMing

    2015-06-01

    In this study, titania-polymer composites with a very high refractive-index tenability and high transparency in the terahertz region were prepared. By controlling the blending ratio of the titania particle, a broad refractive-index tuning range from 1.5 to 3.1 was realized. Then, the composites were used to fabricate antireflective (AR) layers of high-resistivity silicon (HR-Si). By utilizing the thermoplasticity of the titania-polymer composite, a graded-index structure was fabricated via a hot-embossing method. Because of the good refractive-index matching between the composite and the HR-Si substrate, a broadband (0.2-1.6 THz, 7% reflection) AR layer was fabricated.

  11. Superhydrophobic antireflective silica films: fractal surfaces and laser-induced damage thresholds

    Science.gov (United States)

    Xu, Yao; Wu, Dong; Sun, Yu Han; Huang, Zu Xing; Jiang, Xiao Dong; Wei, Xiao Feng; Li, Zhi Hong; Zhong Dong, Bao; Wu, Zhong Hua

    2005-02-01

    Several superhydrophobic antireflective silica films have been prepared by a solgel method that uses hexamethyl-disilizane (HMDS) as a modifier. In a high-power laser, laser-induced damage thresholds (LIDTs) of 23-30 J/cm2 were obtained at 1064-nm wavelength with 1-ns pulse duration. By atomic-force microscopy and optical microscopy, the fractal surfaces of films were studied, and multifractal spectra (MFSs) were calculated both before and after laser damage. The two-sided effect of HMDS on particle growth determined the surface fractal of a particle and the multifractal structure of a film's surface. The bigger Deltaa was, both before and after laser damage, the lower the LIDT was. The effect of methyl groups should be included in the determination of the MFS of the LIDT.

  12. Modification of nanostructured fused silica for use as superhydrophobic, IR-transmissive, anti-reflective surfaces

    Science.gov (United States)

    Boyd, Darryl A.; Frantz, Jesse A.; Bayya, Shyam S.; Busse, Lynda E.; Kim, Woohong; Aggarwal, Ishwar; Poutous, Menelaos; Sanghera, Jasbinder S.

    2016-04-01

    In order to mimic and enhance the properties of moth eye-like materials, nanopatterned fused silica was chemically modified to produce self-cleaning substrates that have anti-reflective and infrared transmissive properties. The characteristics of these substrates were evaluated before and after chemical modification. Furthermore, their properties were compared to fused silica that was devoid of surface features. The chemical modification imparted superhydrophobic character to the substrates, as demonstrated by the average water contact angles which exceeded 170°. Finally, optical analysis of the substrates revealed that the infrared transmission capabilities of the fused silica substrates (nanopatterned to have moth eye on one side) were superior to those of the regular fused silica substrates within the visible and near-infrared region of the light spectrum, with transmission values of 95% versus 92%, respectively. The superior transmission properties of the fused silica moth eye were virtually unchanged following chemical modification.

  13. Monolithically integrated micro- and nanostructured glass surface with antiglare, antireflection, and superhydrophobic properties.

    Science.gov (United States)

    Tulli, Domenico; Hart, Shandon D; Mazumder, Prantik; Carrilero, Albert; Tian, Lili; Koch, Karl W; Yongsunthon, Ruchirej; Piech, Garrett A; Pruneri, Valerio

    2014-07-23

    Hierarchical micro- and nanostructured surfaces have previously been made using a variety of materials and methods, including particle deposition, polymer molding, and the like. These surfaces have attracted a wide variety of interest for applications including reduced specular reflection and superhydrophobic surfaces. To the best of our knowledge, this paper reports the first monolithic, hierarchically structured glass surface that combines micro- and nanoscale surface features to simultaneously generate antiglare (AG), antireflection (AR), and superhydrophobic properties. The AG microstructure mechanically protects the AR nanostructure during wiping and smudging, while the uniform composition of the substrate and the micro- and nanostructured surface enables ion exchange through the surface, so that both the substrate and structured surface can be simultaneously chemically strengthened. PMID:24960031

  14. Efficient antireflective downconversion Er{sup 3+} doped ZnO/Si thin film

    Energy Technology Data Exchange (ETDEWEB)

    Elleuch, R. [Laboratoire Géoressouces, Matériaux, Environnement et Changements Globaux, Faculté des Sciences de Sfax, Université de Sfax, 3018 Sfax (Tunisia); Salhi, R. [Laboratoire de Chimie Industrielle, École Nationale d' Ingénieur de Sfax, Université de Sfax, 3038 Sfax (Tunisia); Al-Quraishi, S.I. [King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Deschanvres, J.-L. [Laboratoire des Matériaux et du Génie Physique, 3 Parvis Louis Néel, BP 257, 38016 Grenoble (France); Maâlej, R., E-mail: ramzi.maalej@fss.rnu.tn [Laboratoire Géoressouces, Matériaux, Environnement et Changements Globaux, Faculté des Sciences de Sfax, Université de Sfax, 3018 Sfax (Tunisia)

    2014-05-01

    This study is an investigation of the potential of Er doped ZnO thin films for downconversion photons and an antireflective layer when placed in front of the silicon solar cells. We optimized the properties of the film with appropriate deposition conditions on Si (111) substrate by aerosol assisted chemical vapor deposition (AACVD) process. An enhancement of both crystallinity and optical response was achieved in the case of film doped with 2.504 at.% Er{sup 3+}. A low reflectance and high refractive index of the film were obtained at around 632 nm. Downconversion process was also reached for this film under visible excitation to near-infrared (NIR) 980 nm photons useful for Si solar cell.

  15. High quality antireflective ZnS thin films prepared by chemical bath deposition

    Energy Technology Data Exchange (ETDEWEB)

    Tec-Yam, S.; Rojas, J.; Rejon, V. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Merida, Departamento de Fisica Aplicada, Km. 6 Antigua Carretera a Progreso, AP 73-Cordemex, 97310 Merida Yucatan (Mexico); Oliva, A.I., E-mail: oliva@mda.cinvestav.mx [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Merida, Departamento de Fisica Aplicada, Km. 6 Antigua Carretera a Progreso, AP 73-Cordemex, 97310 Merida Yucatan (Mexico)

    2012-10-15

    Zinc sulfide (ZnS) thin films for antireflective applications were deposited on glass substrates by chemical bath deposition (CBD). Chemical analysis of the soluble species permits to predict the optimal pH conditions to obtain high quality ZnS films. For the CBD, the ZnCl{sub 2}, NH{sub 4}NO{sub 3}, and CS(NH{sub 2}){sub 2} were fixed components, whereas the KOH concentration was varied from 0.8 to 1.4 M. Groups of samples with deposition times from 60 to 120 min were prepared in a bath with magnetic agitation and heated at 90 Degree-Sign C. ZnS films obtained from optimal KOH concentrations of 0.9 M and 1.0 M exhibited high transparency, homogeneity, adherence, and crystalline. The ZnS films presented a band gap energy of 3.84 eV, an atomic Zn:S stoichiometry ratio of 49:51, a transmittance above 85% in the 300-800 nm wavelength range, and a reflectance below 25% in the UV-Vis range. X-ray diffraction analysis revealed a cubic structure in the (111) orientation for the films. The thickness of the films was tuned between 60 nm and 135 nm by controlling the deposition time and KOH concentration. The incorporation of the CBD-ZnS films into ITO/ZnS/CdS/CdTe and glass/Mo/ZnS heterostructures as antireflective layer confirms their high optical quality. -- Highlights: Black-Right-Pointing-Pointer High quality ZnS thin films were prepared by chemical bath deposition (CBD). Black-Right-Pointing-Pointer Better CBD-ZnS films were achieved by using 0.9 M-KOH concentration. Black-Right-Pointing-Pointer Reduction in the reflectance was obtained for ZnS films used as buffer layers.

  16. Morbus Coats

    Science.gov (United States)

    Förl, B.; Schmack, I.; Grossniklaus, H.E.; Rohrschneider, K.

    2010-01-01

    Der fortgeschrittene Morbus Coats stellt im Kleinkindalter eine der schwierigsten Differenzialdiagnosen zum Retinoblastom dar. Wir beschreiben die klinischen und histologischen Befunde zweier Jungen im Alter von 9 und 21 Monaten mit einseitiger Leukokorie. Trotz umfassender Diagnostik mittels Narkoseuntersuchung, MRT und Ultraschall konnte ein Retinoblastom nicht sicher ausgeschlossen werden, und es erfolgte eine Enukleation. Histologisch wurde die Diagnose eines Morbus Coats gesichert. Da eine differenzialdiagnostische Abgrenzung zwischen Morbus Coats und Retinoblastom schwierig sein kann, halten wir in zweifelhaften Fällen auch angesichts der eingeschränkten Visusprognose und potenzieller Sekundärkomplikationen beim fortgeschrittenen Morbus Coats eine Enukleation für indiziert. PMID:18299842

  17. The Development, Application And Testing Of Diamond-Like Coatings For Infra-Red Components

    Science.gov (United States)

    Lettington, A. H.

    1986-05-01

    The lack of durability of the outermost coated lens or window of thermal imaging systems had been a problem for many years. It was overcome in the mid-seventies by the development within RSRE of the infra-red transparent diamond-like carbon coating. This material was chemically durable, abrasion resistant and a near perfect match to germanium as a single layer anti-reflection coating. Originally the coatings had reasonable infra-red transmission but their hardness and adhesion were variable. Using our own processes we obtained consistently good coatings with optimised transmission. The application and excellent performance of these coatings on germanium components is described. Another application is the protection of diamond flycut aluminium surfaces where the off-normal reflectivity in the infra-red using conventional coatings can be poor. Having developed these coatings it was then necessary to develop specifications before they could be used in service. The development of coatings test procedures and specifications is also described.

  18. Silicon nitride and intrinsic amorphous silicon double antireflection coatings for thin-film solar cells on foreign substrates

    International Nuclear Information System (INIS)

    Hydrogenated intrinsic amorphous silicon (a-Si:H) was investigated as a surface passivation method for crystalline silicon thin film solar cells on graphite substrates. The results of the experiments, including quantum efficiency and current density-voltage measurements, show improvements in cell performance. This improvement is due to surface passivation by an a-Si:H(i) layer, which increases the open circuit voltage and the fill factor. In comparison with our previous work, we have achieved an increase of 0.6% absolute cell efficiency for a 40 μm thick 4 cm2 aperture area on the graphite substrate. The optical properties of the SiNx/a-Si:H(i) stack were studied using spectroscopic ellipsometer techniques. Scanning transmission electron microscopy inside a scanning electron microscope was applied to characterize the cross section of the SiNx/a-Si:H(i) stack using focus ion beam preparation. - Highlights: • We report a 10.8% efficiency for thin-film silicon solar cell on graphite. • Hydrogenated intrinsic amorphous silicon was applied for surface passivation. • SiNx/a-Si:H(i) stacks were characterized by spectroscopic ellipsometer techniques. • Cross-section micrograph was obtained by scanning transmission electron microscopy. • Quantum efficiency and J-V measurements show improvements in the cell performance

  19. Silicon nitride and intrinsic amorphous silicon double antireflection coatings for thin-film solar cells on foreign substrates

    Energy Technology Data Exchange (ETDEWEB)

    Li, Da; Kunz, Thomas [Bavarian Center for Applied Energy Research (ZAE Bayern), Division: Photovoltaics and Thermosensoric, Haberstr. 2a, 91058 Erlangen (Germany); Wolf, Nadine [Bavarian Center for Applied Energy Research (ZAE Bayern), Division: Energy Efficiency, Am Galgenberg 87, 97074 Wuerzburg (Germany); Liebig, Jan Philipp [Materials Science and Engineering, Institute I, University of Erlangen-Nuremberg, Martensstr. 5, 91058 Erlangen (Germany); Wittmann, Stephan; Ahmad, Taimoor; Hessmann, Maik T.; Auer, Richard [Bavarian Center for Applied Energy Research (ZAE Bayern), Division: Photovoltaics and Thermosensoric, Haberstr. 2a, 91058 Erlangen (Germany); Göken, Mathias [Materials Science and Engineering, Institute I, University of Erlangen-Nuremberg, Martensstr. 5, 91058 Erlangen (Germany); Brabec, Christoph J. [Bavarian Center for Applied Energy Research (ZAE Bayern), Division: Photovoltaics and Thermosensoric, Haberstr. 2a, 91058 Erlangen (Germany); Institute of Materials for Electronics and Energy Technology, University of Erlangen-Nuremberg, Martensstr. 7, 91058 Erlangen (Germany)

    2015-05-29

    Hydrogenated intrinsic amorphous silicon (a-Si:H) was investigated as a surface passivation method for crystalline silicon thin film solar cells on graphite substrates. The results of the experiments, including quantum efficiency and current density-voltage measurements, show improvements in cell performance. This improvement is due to surface passivation by an a-Si:H(i) layer, which increases the open circuit voltage and the fill factor. In comparison with our previous work, we have achieved an increase of 0.6% absolute cell efficiency for a 40 μm thick 4 cm{sup 2} aperture area on the graphite substrate. The optical properties of the SiN{sub x}/a-Si:H(i) stack were studied using spectroscopic ellipsometer techniques. Scanning transmission electron microscopy inside a scanning electron microscope was applied to characterize the cross section of the SiN{sub x}/a-Si:H(i) stack using focus ion beam preparation. - Highlights: • We report a 10.8% efficiency for thin-film silicon solar cell on graphite. • Hydrogenated intrinsic amorphous silicon was applied for surface passivation. • SiN{sub x}/a-Si:H(i) stacks were characterized by spectroscopic ellipsometer techniques. • Cross-section micrograph was obtained by scanning transmission electron microscopy. • Quantum efficiency and J-V measurements show improvements in the cell performance.

  20. Fabrication of highly ordered CuInSe{sub 2} films with hollow nanocones for anti-reflection

    Energy Technology Data Exchange (ETDEWEB)

    Xiao Jinrong [National Laboratory of Solid State Microstructures and Jiangsu Provincial Key Laboratory of Photonic and Electronic Materials Sciences and Technology, School of Electronic Science and Engineering, Nanjing University, No. 22 Han Kou Road, Nanjing 210093 (China); Xu Ling, E-mail: xuling@nju.edu.cn [National Laboratory of Solid State Microstructures and Jiangsu Provincial Key Laboratory of Photonic and Electronic Materials Sciences and Technology, School of Electronic Science and Engineering, Nanjing University, No. 22 Han Kou Road, Nanjing 210093 (China); Geng Lei; Tong Liang; Yang Fei; Xu Jun [National Laboratory of Solid State Microstructures and Jiangsu Provincial Key Laboratory of Photonic and Electronic Materials Sciences and Technology, School of Electronic Science and Engineering, Nanjing University, No. 22 Han Kou Road, Nanjing 210093 (China); Su Weining [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China); Liu Dong [National Laboratory of Solid State Microstructures and Jiangsu Provincial Key Laboratory of Photonic and Electronic Materials Sciences and Technology, School of Electronic Science and Engineering, Nanjing University, No. 22 Han Kou Road, Nanjing 210093 (China); Yu Yao [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China); Ma Zhongyuan; Chen Kunji [National Laboratory of Solid State Microstructures and Jiangsu Provincial Key Laboratory of Photonic and Electronic Materials Sciences and Technology, School of Electronic Science and Engineering, Nanjing University, No. 22 Han Kou Road, Nanjing 210093 (China)

    2011-10-01

    Highly ordered CuInSe{sub 2} films with hollow nanocones were fabricated by electron beam evaporation and nanospheres lithograph. From the AFM analyses, polystyrene nanospheres with diameter of 220 nm are assembled regularly on glass substrates. After reaction ion etching under different powers and residues removal, different and new surface morphologies of substrates have been obtained, such as smooth nanocones and hollow nanocones. The diffuse reflection spectra demonstrate that films on the substrates with periodic nanopatterned structure have less reflection over wavelengths ranged from 200 nm to 2500 nm due to light trapping. Especially, reflection for hollow nanocone arrays has the larger suppression value than nanocone-patterned films, which proves that surface pattern of hollow nanocones has better anti-reflection effect. Furthermore, while hollow depth increases from 6 nm to 9 nm, its optical antireflective effect becomes remarkable. These results could yield new options for solar-cell design with higher energy conversion efficiency.

  1. Influence of window layer thickness on double layer antirefiection coating for triple junction solar cells*

    Institute of Scientific and Technical Information of China (English)

    Wang Lijuan; Zhan Feng; Yu Ying; Zhu Yan; Liu Shaoqing; Huang Shesong; Ni Haiqiao; Niu Zhichuan

    2011-01-01

    The optimization of a SiO2/TiO2, SiO2/ZnS double layer antireflection coating (ARC) on Ga0.5ln0.5P/ln0.02Ga0.98As/Ge solar cells for terrestrial application is discussed. The Al0.5In0.5P window layer thickness is also taken into consideration. It is shown that the optimal parameters of double layer ARC vary with the thickness of the window layer.

  2. Low-cost, flexible, and self-cleaning 3D nanocone anti-reflection films for high-efficiency photovoltaics.

    Science.gov (United States)

    Tsui, Kwong-Hoi; Lin, Qingfeng; Chou, Hungtao; Zhang, Qianpeng; Fu, Huiying; Qi, Pengfei; Fan, Zhiyong

    2014-05-01

    Low-cost engineered nanotemplates are used to mold flexible nanocone anti-reflection (AR) films. Both optical reflectance measurements and photovoltaics characterizations demonstrate that the flexible nanocone AR films can considerably suppress device front-side reflectance and thus improve the power conversion efficiency of high-efficiency thin-film CdTe solar cells. Additionally, these nanocone AR films are found to be superhydrophobic and thus possess self-cleaning capability. PMID:24448979

  3. Lithography-Free, Low-Cost Method for Improving Photodiode Performance by Etching Silicon Nanocones as Antireflection Layer

    CERN Document Server

    Jiang, Jing; Lin, Jiahao; Liu, Gang Logan

    2016-01-01

    A three-step process has been demonstrated to improve the performance of photodiode by creating nanocone forest on the surface of photodiode as an antireflection layer. This high-throughput, low-cost process has been shown to decrease the reflectivity by 66.1%, enhance the quantum efficiency by 27%, and increase the responsivity by 25.7%. This low-cost manufacture process can be applied to increase the responsivity of silicon based photonic devices.

  4. Sol-gel preparation and characterization of SiO2 coated VO2 films with enhanced transmittance and high thermochromic performance

    Science.gov (United States)

    Li, Dezeng; Shan, Yongkui; Huang, Fuqiang; Ding, Shangjun

    2014-10-01

    Vanadium dioxide (VO2) films prepared at low-temperature with a low cost are considerable for energy-saving applications. Here, SiO2 coated VO2 films with clearly enhanced visible transmittance by introducing antireflection coatings (ARCs) and excellent thermochromic performance were present. The VO2 films have been prepared via a stable and low-cost sol-gel synthesis route using vanadium pentaoxide powder as precursor, and their structural, morphological, optical and electrical properties and thermochromic performance were systemically characterized. The resistance of VO2 films varies by 4 orders of magnitude and the transmittance changes from 11.8% to 69.3% at 2500 nm while no significant deviation appears in the visible region during metal-insulator transition (MIT). Nanoporous SiO2 coating with good optical transparency was coated on the surface of VO2 film via sol-gel dip-coating technique to enhance its optical transmittance, and the visible transmittance is increased by 14.6% due to the significantly decreased reflectance. The critical transition temperature (63 °C) and infrared switching properties of VO2 films are not much deteriorated by applying SiO2 layer. The synergistic effect of antireflection and thermochromism on SiO2 coated VO2 films was investigated.

  5. Omnidirectional antireflective properties of porous tungsten oxide films with in-depth variation of void fraction and stoichiometry

    Science.gov (United States)

    Vourdas, Nikolaos; Dalamagkidis, Konstantinos; Kostis, Ioannis; Vasilopoulou, Maria; Davazoglou, Dimitrios

    2012-11-01

    We report on the fabrication of porous hot-wire deposited WOx (hwWOx) films with omnidirectional antireflective properties coming from in-depth variation of both (i) void fraction from 0% at the Si substrate/hwWOx interface to 30% within less than 7 nm and to higher than 50% at the hwWOx/air interface, and (ii) x, namely hwWOx stoichiometry, from 2.5 at the Si/hwWOx to 3 within less than 7 nm. hwWOx films were deposited by means of hw deposition at rough vacuum and controlled chamber environment. The films were analyzed by Spectroscopic Ellipsometry to extract the graded refractive index profile, which was then used in a rigorous coupled wave analysis (RCWA) model to simulate the antireflective properties. RCWA followed reasonably the experimental reflection measurements. Void fraction and x in-depth variation, controlled by the hw process, greatly affect the antireflective properties, and improve the omnidirectional and broadband characteristics. The reflection suppression below 10% within the range of 500-1000 nm for angles of incidence up to more than 60° is demonstrated.

  6. Flat-top and patterned-topped cone gratings for visible and mid-infrared antireflective properties.

    Science.gov (United States)

    Brückner, Jean-Baptiste; Le Rouzo, Judikaël; Escoubas, Ludovic; Berginc, Gérard; Gourgon, Cécile; Desplats, Olivier; Simon, Jean-Jacques

    2013-07-01

    Achieving a broadband antireflection property from material surfaces is one of the highest priorities for those who want to improve the efficiency of solar cells or the sensitivity of photo-detectors. To lower the reflectance of a surface, we are concerned with the study of the optical response of flat-top and patterned-topped cone shaped silicon gratings, based on previous work exploring pyramid gratings. Through rigorous numerical methods such as Finite Different Time Domain, we first designed several flat-top structures that theoretically demonstrate an antireflective character within the middle infrared region. From the opto-geometrical parameters such as period, depth and shape of the pattern determined by numerical analysis, these structures have been fabricated using controlled slope plasma etching processes. In order to extend the antireflective properties up to the visible wavelengths, patterned-topped cones have been fabricated as well. Afterwards, optical characterizations of several samples were carried out. Thus, the performances of the flat-top and patterned-topped cones have been compared in the visible and mid infrared range. PMID:23842391

  7. Structure and antireflection properties of SiNWs arrays form mc-Si wafer through Ag-catalyzed chemical etching

    Science.gov (United States)

    Li, Shaoyuan; Ma, Wenhui; Chen, Xiuhua; Xie, Keqiang; Li, Yuping; He, Xiao; Yang, Xi; Lei, Yun

    2016-04-01

    A simple and low cost MACE method was demonstrated for efficiently texturing commercial mc-Si wafer at room temperature. The effects of fabrication parameters (deposition time, HF concentration, H2O2 concentration, and etching time) on the morphology structure, antireflection property of textured mc-Si were carefully studied. The large scale SiNWs arrays with different structure can be obtained under various fabrication conditions. Meanwhile, the results indicate that the fabricate parameters have important effect on the reflectance of textured mc-Si sample in the order of etching time > deposition time > H2O2 concentration > HF concentration. The comprehensive research results indicate that it is more beneficial for the nanowire arrays with tapering structure and the length of 13 μm to obtain excellent antireflection property. Under these optimization conditions, the textured mc-Si shows an outstanding anti-reflectance ability of ∼5.6%, which indicates that the Ag-catalysis etched mc-Si shows a huge potential application in high-efficiency polysilicon solar cells.

  8. Improvement of MgF 2 thin coating films for laser applications

    Science.gov (United States)

    Perales, F.; Herrero, J. M.; Jaque, D.; de las Heras, C.

    2007-03-01

    MgF2 thin films have been deposited by physical vapor deposition on different substrates (laser crystals, a saturable absorber crystal and glasses), in order to investigate the best conditions for antireflection coatings. The relevance of using these MgF2 coatings has been evidenced by different laser gain experiments performed on different coated and uncoated elements such as Nd:CGGG, Nd:LiNbO3 and Cr4+:YAG. Then the optical properties of the MgF2 films have been systematically investigated for different annealing temperatures and ion bombardment treatments. A substantial improvement in the films transmission has been demonstrated. The obtained results are correlated to morphologic changes in the MgF2 films.

  9. Sol–gel preparation and characterization of SiO{sub 2} coated VO{sub 2} films with enhanced transmittance and high thermochromic performance

    Energy Technology Data Exchange (ETDEWEB)

    Li, Dezeng [Department of Chemistry, East China Normal University, Shanghai 200241 (China); Shan, Yongkui, E-mail: ykshan@chem.ecnu.edu.cn [Department of Chemistry, East China Normal University, Shanghai 200241 (China); Huang, Fuqiang, E-mail: huangfq@mail.sic.ac.cn [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); National Laboratory of Molecular Science and State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Ding, Shangjun [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China)

    2014-10-30

    Highlights: • VO{sub 2} films have been prepared via a stable and low-cost sol–gel synthesis route and were systemically characterized. • SiO{sub 2}/VO{sub 2} films were fabricated with increased transmittance and high thermochromic performance. • The synergistic effect of antireflection and thermochromism on SiO{sub 2}/VO{sub 2} films was investigated. - Abstract: Vanadium dioxide (VO{sub 2}) films prepared at low-temperature with a low cost are considerable for energy-saving applications. Here, SiO{sub 2} coated VO{sub 2} films with clearly enhanced visible transmittance by introducing antireflection coatings (ARCs) and excellent thermochromic performance were present. The VO{sub 2} films have been prepared via a stable and low-cost sol–gel synthesis route using vanadium pentaoxide powder as precursor, and their structural, morphological, optical and electrical properties and thermochromic performance were systemically characterized. The resistance of VO{sub 2} films varies by 4 orders of magnitude and the transmittance changes from 11.8% to 69.3% at 2500 nm while no significant deviation appears in the visible region during metal–insulator transition (MIT). Nanoporous SiO{sub 2} coating with good optical transparency was coated on the surface of VO{sub 2} film via sol–gel dip-coating technique to enhance its optical transmittance, and the visible transmittance is increased by 14.6% due to the significantly decreased reflectance. The critical transition temperature (63 °C) and infrared switching properties of VO{sub 2} films are not much deteriorated by applying SiO{sub 2} layer. The synergistic effect of antireflection and thermochromism on SiO{sub 2} coated VO{sub 2} films was investigated.

  10. Sprayed coatings

    Science.gov (United States)

    Steffens, H. D.

    1980-03-01

    Thermal spraying is shown to be an efficient means for the protection of surface areas against elevated temperature, wear, corrosion, hot gas corrosion, and erosion in structural aircraft components. Particularly in jet engines, numerous parts are coated by flame, detonation, or plasma spraying techniques. The applied methods of flame, detonation, and plasma spraying are explained, as well as electric arc spraying. Possibilities for spray coatings which meet aircraft service requirements are discussed, as well as methods for quality control, especially nondestructive test methods. In particular, coating characteristics and properties obtained by different spray methods are described, and special attention is paid to low pressure plasma spraying.

  11. Towards perfect light coupling and absorption in nanomembranes with omni-directional anti-reflection and photonic crystal structures

    Science.gov (United States)

    Chadha, Arvinder Singh

    investigated in detail. The front-surface Fresnel reflection is reduced with the incorporation of an omni-directional anti-reflection coating (Omni-ARC) based on nanostructures or by deposition of graded refractive index (GRIN) films. A design methodology based on the comparison of the rate of change of the refractive index profile of nanostructures of different shapes and thickness as an equivalent GRIN film suggests the minimum feature size needed to give near perfect ARC. Numerical models were built to account for the non - uniform GRIN film deposition on both rigid and flexible, flat and curved surfaces resulting from the variation in the resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) process technology. With the miniaturization of the devices, the effect of finite beam size and finite active area of the photonic components on the optical properties like transmission, reflection and scattering loss was studied as well. All the numerical studies presented in the thesis are validated by experimental results.

  12. Large-Aperture Wide-Bandwidth Anti-Reflection-Coated Silicon Lenses for Millimeter Wavelengths

    Science.gov (United States)

    Datta, R.; Munson, C. D.; Niemack, M. D.; McMahon, J. J.; Britton, J.; Wollack, E. J.; Beall, J.; Devlin, M. J.; Fowler, J.; Gallardo, P.; Hubmayr, J.; Irwin, K.; Newburgh, L.; Nibarger, J. P.; Page, L.; Quijada, M. A.; Schmitt, B. L.; Staggs, S. T.; Thornton, R.; Zhang, L.

    2013-01-01

    The increasing scale of cryogenic detector arrays for sub-millimeter and millimeter wavelength astrophysics has led to the need for large aperture, high index of refraction, low loss, cryogenic refracting optics. Silicon with n = 3.4, low loss, and relatively high thermal conductivity is a nearly optimal material for these purposes, but requires an antireflection (AR) coating with broad bandwidth, low loss, low reflectance, and a matched coffecient of thermal expansion. We present an AR coating for curved silicon optics comprised of subwavelength features cut into the lens surface with a custom three axis silicon dicing saw. These features constitute a metamaterial that behaves as a simple dielectric coating. We have fabricated and coated silicon lenses as large as 33.4 cm in diameter with coatings optimized for use between 125-165 GHz. Our design reduces average reflections to a few tenths of a percent for angles of incidence up to 30 deg. with low cross-polarization. We describe the design, tolerance, manufacture, and measurements of these coatings and present measurements of the optical properties of silicon at millimeter wavelengths at cryogenic and room temperatures. This coating and lens fabrication approach is applicable from centimeter to sub-millimeter wavelengths and can be used to fabricate coatings with greater than octave bandwidth.

  13. Hard coatings

    OpenAIRE

    Dan, J.; Boving, H.; Hintermann, H.

    1993-01-01

    Hard, wear resistant and low friction coatings are presently produced on a world-wide basis, by different processes such as electrochemical or electroless methods, spray technologies, thermochemical, CVD and PVD. Some of the most advanced processes, especially those dedicated to thin film depositions, basically belong to CVD or PVD technologies, and will be looked at in more detail. The hard coatings mainly consist of oxides, nitrides, carbides, borides or carbon. Over the years, many process...

  14. Hierarchically porous micro/nanostructured copper surfaces with enhanced antireflection and hydrophobicity

    Science.gov (United States)

    Li, Ming; Su, Yanjie; Hu, Jing; Yao, Lu; Wei, Hao; Yang, Zhi; Zhang, Yafei

    2016-01-01

    A facile hydrothermal method has been proposed to fabricate hierarchically porous Cu micro/nanostructures on Cu foil, whose growth can be controlled by the reaction time and the amount of ethylene glycol added into the precursor. Compared to commercially available Cu foil, the micro/nanostructured Cu surfaces exhibit not only greatly enhanced ability to absorb light over a wide range of wavelengths from 250 to 1000 nm, but also improved hydrophobicity from 90.4° to 151.2° without any low-surface-energy chemical modification. The reflectance can reach a lowest value of 10% at 300 nm and show a biggest decrement of 53% at 582 nm. Due to their superhydrophobicity, the micro/nanostructured Cu foils demonstrate an improved anticorrosion ability against 3.5 wt% NaCl solution compared with a bare one. The proposed mechanism indicates that the combination of the dual-scale roughness and the adsorbed air in pores account for the enhanced antireflection and hydrophobicity.

  15. Enhanced power generation in concentrated photovoltaics using broadband antireflective coverglasses with moth eye structures.

    Science.gov (United States)

    Song, Young Min; Jeong, Yonkil; Yeo, Chan Il; Lee, Yong Tak

    2012-11-01

    We present the effect of broadband antireflective coverglasses (BARCs) with moth eye structures on the power generation capability of a sub-receiver module for concentrated photovoltaics. The period and height of the moth eye structures were designed by a rigorous coupled-wave analysis method in order to cover the full solar spectral ranges without transmission band shrinkage. The BARCs with moth eye structures were prepared by the dry etching of silver (Ag) nanomasks, and the fabricated moth eye structures on coverglass showed strongly enhanced transmittance compared to the bare glass with a flat surface, at wavelengths of 300 - 1800 nm. The BARCs were mounted on InGaP/GaAs/Ge triple-junction solar cells and the power conversion efficiency of this sub-receiver module reached 42.16% for 196 suns, which is a 7.41% boosted value compared to that of a module with bare coverglass, without any detrimental changes of the open circuit voltages (V(oc)) and fill factor (FF). PMID:23326839

  16. Improving the imaging intensity of a photonic crystal flat lens by an antireflection method

    Science.gov (United States)

    Sun, J.; Shen, Y. F.; Wang, L. G.; Zhou, J.; Zhang, Y.; Wang, Y. C.; Chen, J.; Han, K.; Tang, G.

    2011-05-01

    In this paper, a two-dimensional photonic crystal (PC) consisting of a triangular lattice of silicon rods in air is studied theoretically. Equal-frequency contours (EFCs) analysis shows that this PC structure exhibits an effective refractive index neff = -1 at a normalized frequency ω=0.30×2πc/a. A superlens effect is demonstrated using this PC structure by the finite-difference time-domain (FDTD) simulation. An antireflection layer (ARL) is introduced into the PC slab surface in order to achieve a high-intensity image. Two point sources imaging process is also simulated both in the case of a perfect PC structure and in the case of a PC structure with an ARL. The results show that the method of introducing the ARL into the PC surface is effectual for improving both the intensity of the image and the capability of the super-resolution of two sources, which are in accord with the coupled-mode theory analysis. Theoretical study implies that the surface defect modes play an important role in enhancing the transmitted intensity of energy flow.

  17. Durable solgel antireflective films with high laser-induced damage thresholds for inertial confinement fusion

    Science.gov (United States)

    Xu, Yao; Zhang, Lei; Wu, Dong; Sun, Yu Han; Huang, Zu Xing; Jiang, Xiao Dong; Wei, Xiao Feng; Li, Zhi Hong; Dong, Bao Zhong; Wu, Zhong Hua

    2005-04-01

    We tested the use of two hydrophobic methyl-substituted silane precursors, methyltriethoxysilane and dimethyldiethoxysilane, to synthesize methyl-modified silica sols by a two-step method and a cohydrolysis method to produce durable antireflective films with high laser-induced-damage thresholds (LIDTs). Using small-angle x-ray scattering technology, we obtained details of the microstructure of clusters in sol and found various double fractal structural characteristics in the methyl-modified silica clusters; our findings were confirmed by transmission-electron micrographs. Through a 29Si magic-angle spin nuclear magnetic resonance study of the corresponding xerogels, we determined the double-fractal microstructure, which we then related to the LIDTs of AR films. The distribution configuration of methyls in clusters determined the double-fractal microstructure of clusters and then the LIDTs of AR films. The LIDTs of films produced by the cohydrolysis method (the highest was 38 J/cm2 for 1-ns, 1064-nm laser action) were much higher than those from the two-step method because of the loose netlike clusters in the former configuration. During the 220-day aging, the transmittance of hydrophobic AR film decreased ~0.2%. So it is practicable to prepare durable AR films with higher LIDTs than those of normal AR SiO2 films only by introducing hydrophobic methyls into a Si-O-Si matrix of clusters if an appropriate hydrophobic precursor is chosen.

  18. Antireflective nanostructures fabricated by reactive ion etching method on pyramid-structured silicon surface

    International Nuclear Information System (INIS)

    In this paper, pyramid-structured silicon wafers were etched in a reactive ion etching system at room temperature and without any negative voltage pulses to obtain antireflective nanostructures. The effects of the etching time, etching power and the flow ratio of the SF6 and O2 (FSF6/FO2) on the morphologies and reflective properties of the etched samples were studied. Scanning electron microscope was used to investigate the morphologies of etched samples. The surface reflectance measurements were carried out using UV–vis-NIR spectrophotometer. A reflectance of 4.72% from the etched surface in the wavelength range of 400–800 nm was obtained under etching time of 20 min, etching power of 150 W and FSF6/FO2 of 18 sccm/6 sccm. Meanwhile, samples etched with FO2 lower than 6 sccm can’t get low reflective silicon structure. Besides, the results show that overlong etching time of 30 min and too big etching power of 225 W would make the nanostructures too sparse to obtain a low reflectance.

  19. Antireflective nanostructures fabricated by reactive ion etching method on pyramid-structured silicon surface

    Energy Technology Data Exchange (ETDEWEB)

    Yue, Zhihao [College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing 210016 (China); Shen, Honglie, E-mail: hlshen@nuaa.edu.cn [College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing 210016 (China); Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education, Institute of Nanoscience, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing 210016 (China); Jiang, Ye [College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing 210016 (China)

    2013-04-15

    In this paper, pyramid-structured silicon wafers were etched in a reactive ion etching system at room temperature and without any negative voltage pulses to obtain antireflective nanostructures. The effects of the etching time, etching power and the flow ratio of the SF{sub 6} and O{sub 2} (F{sub SF6}/F{sub O2}) on the morphologies and reflective properties of the etched samples were studied. Scanning electron microscope was used to investigate the morphologies of etched samples. The surface reflectance measurements were carried out using UV–vis-NIR spectrophotometer. A reflectance of 4.72% from the etched surface in the wavelength range of 400–800 nm was obtained under etching time of 20 min, etching power of 150 W and F{sub SF6}/F{sub O2} of 18 sccm/6 sccm. Meanwhile, samples etched with F{sub O2} lower than 6 sccm can’t get low reflective silicon structure. Besides, the results show that overlong etching time of 30 min and too big etching power of 225 W would make the nanostructures too sparse to obtain a low reflectance.

  20. Multifunctional porous silicon nanopillar arrays: antireflection, superhydrophobicity, photoluminescence, and surface-enhanced Raman scattering

    International Nuclear Information System (INIS)

    We have fabricated porous silicon nanopillar arrays over large areas with a rapid, simple, and low-cost technique. The porous silicon nanopillars show unique longitudinal features along their entire length and have porosity with dimensions on the single-nanometer scale. Both Raman spectroscopy and photoluminescence data were used to determine the nanocrystallite size to be <3 nm. The porous silicon nanopillar arrays also maintained excellent ensemble properties, reducing reflection nearly fivefold from planar silicon in the visible range without any optimization, and approaching superhydrophobic behavior with increasing aspect ratio, demonstrating contact angles up to 138°. Finally, the porous silicon nanopillar arrays were made into sensitive surface-enhanced Raman scattering (SERS) substrates by depositing metal onto the pillars. The SERS performance of the substrates was demonstrated using a chemical dye Rhodamine 6G. With their multitude of properties (i.e., antireflection, superhydrophobicity, photoluminescence, and sensitive SERS), the porous silicon nanopillar arrays described here can be valuable in applications such as solar harvesting, electrochemical cells, self-cleaning devices, and dynamic biological monitoring. (paper)

  1. Broadband terahertz anti-reflective structure fabricated by femtosecond laser drilling technique

    Science.gov (United States)

    Zhang, Yibin; Yuan, Minghui; Chen, Lin; Cai, Bin; Yang, Rui; Zhu, Yiming

    2016-02-01

    We fabricated several reverse conical holes on high-resistivity silicon substrate with different power and pulse number of femtosecond laser, and investigated their patterns and features by using scanning electron microscope (SEM). Then, we chose one of the experimental parameters prepared a reverse conical anti-reflection structure sample with period of 90 μm. Terahertz Time-domain Spectroscopy (THz-TDS) was used to test its properties. Compared with the nonstructural high-resistivity silicon, the transmission of structural high-resistivity silicon increases by the maximum of 14% in the range 0.32-1.30 THz. Furthermore, we simulated the sample by finite integral method (FIM). The simulated results show good consistency with experimental results. The transmission effect of the reverse conical holes were optimized via simulation. Results show that the related transmission effect can be improved by increasing the pulse numbers and decreasing the spot size of the femtosecond laser. The different transmission window can also be tuned by changing the reverse conical structure of different periods.

  2. Broadband Antireflection and Light Extraction Enhancement in Fluorescent SiC with Nanodome Structures

    DEFF Research Database (Denmark)

    Ou, Yiyu; Zhu, Xiaolong; Jokubavicius, Valdas;

    2014-01-01

    We demonstrate a time-efficient and low-cost approach to fabricate Si3N4 coated nanodome structures in fluorescent SiC. Nanosphere lithography is used as the nanopatterning method and SiC nanodome structures with Si3N4 coating are formed via dry etching and thin film deposition process. By using...

  3. Hard coatings

    International Nuclear Information System (INIS)

    Hard, wear resistant and low friction coatings are presently produced on a world-wide basis, by different processes such as electrochemical or electroless methods, spray technologies, thermochemical, CVD and PVD. Some of the most advanced processes, especially those dedicated to thin film depositions, basically belong to CVD or PVD technologies, and will be looked at in more detail. The hard coatings mainly consist of oxides, nitrides, carbides, borides or carbon. Over the years, many processes have been developed which are variations and/or combinations of the basic CVD and PVD methods. The main difference between these two families of deposition techniques is that the CVD is an elevated temperature process (≥ 700 C), while the PVD on the contrary, is rather a low temperature process (≤ 500 C); this of course influences the choice of substrates and properties of the coating/substrate systems. Fundamental aspects of the vapor phase deposition techniques and some of their influences on coating properties will be discussed, as well as the very important interactions between deposit and substrate: diffusions, internal stress, etc. Advantages and limitations of CVD and PVD respectively will briefly be reviewed and examples of applications of the layers will be given. Parallel to the development and permanent updating of surface modification technologies, an effort was made to create novel characterisation methods. A close look will be given to the coating adherence control by means of the scratch test, at the coating hardness measurement by means of nanoindentation, at the coating wear resistance by means of a pin-on-disc tribometer, and at the surface quality evaluation by Atomic Force Microscopy (AFM). Finally, main important trends will be highlighted. (orig.)

  4. Coatings for high energy applications. The Nova laser

    International Nuclear Information System (INIS)

    The combined requirements of energy density, multiple wavelength, and aperture make the coatings for the Nova Inertial Confinement Fusion (ICF) laser unique. This ten beam neodymium glass laser system, built at the Lawrence Livermore National Laboratory (LLNL), has over a thousand major optical components; some larger than one meter in diameter and weighing 380 Kg. The laser operates at 1054 nm and can be frequency doubled to 527 nm or tripled to 351 nm by means of full aperture potassium dihydrogen phosphate (KDP) crystal arrays. The 1.0 nsec fluence varies along the laser chain, sometimes reaching values as high as 16 J/cm2 at the input lens to one of the spatial filters. The design specifications of this massive optical system were changed several times as the state-of-the-art advanced. Each change required redesign of the optical coatings even as vendors were preparing for production runs. Frequency conversion to include shorter wavelengths mandated the first major coating redesign and was followed almost immediately by a second redesign to reduce solarization effects in borosilicate crown glass. The conventional thermal evaporation process although successful for the deposition of mirror coatings, was not able to produce antireflection coatings able to survive the locally high chain fluences. As a consequence it became necessary to develop another technique. Solution produced coatings were developed having transmissions exceeding 99% per part and damage threshold values equal to the bare substrate. The unique requirement of the Nova laser necessitated special deposition and metrology equipment. These programmatic developments will be reviewed in the context of the cooperative working relationship developed between LLNL and its vendors. It was this excellent relationship which has enabled LLNL to obtain these highly specialized coatings for the Nova laser

  5. Fabrication of hierarchical anti-reflective structures using polystyrene sphere lithography on an as-cut p-Si substrate

    Science.gov (United States)

    Chou, Yen-Yu; Lee, Kuan-Tao; Lee, Yeeu-Chang

    2016-07-01

    The broadband anti-reflective (AR) properties of hierarchical structures (HSs) have attracted considerable attention in recent years as a means to reduce Fresnel reflection in photovoltaic solar cell materials. This study employed polystyrene sphere lithography in conjunction with high density plasma dry etching in the fabrication of pure sub-wavelength structures and HSs on an as-cut p-Si substrate. Etching parameters, such as RF power, O2, and etching time, were adjusted to alter the surface morphology. Experiment results demonstrate that the resulting hierarchical paraboloidal structures suppress average reflectance to below 0.5% across a spectral range of 500-1000 nm.

  6. A two-in-one superhydrophobic and anti-reflective nanodevice in the grey cicada Cicada orni (Hemiptera)

    Energy Technology Data Exchange (ETDEWEB)

    Dellieu, Louis, E-mail: louis.dellieu@unamur.be; Sarrazin, Michaël, E-mail: michael.sarrazin@unamur.be; Simonis, Priscilla; Deparis, Olivier; Vigneron, Jean Pol [Research Center in Physics of Matter and Radiation (PMR), Department of Physics, University of Namur (FUNDP), 61 rue de Bruxelles, B-5000 Namur (Belgium)

    2014-07-14

    Two separated levels of functionality are identified in the nanostructure which covers the wings of the grey cicada Cicada orni (Hemiptera). The upper level is responsible for superhydrophobic character of the wing, while the lower level enhances its anti-reflective behavior. Extensive wetting experiments with various chemical species and optical measurements were performed in order to assess the bi-functionality. Scanning electron microscopy imaging was used to identify the nanostructure morphology. Numerical optical simulations and analytical wetting models were used to prove the roles of both levels of the nanostructure. In addition, the complex refractive index of the chitinous material of the wing was determined from measurements.

  7. A two-in-one superhydrophobic and anti-reflective nanodevice in the grey cicada $\\textit{Cicada orni}$ (Hemiptera)

    CERN Document Server

    Dellieu, Louis; Simonis, Priscilla; Deparis, Olivier; Vigneron, Jean Pol

    2014-01-01

    Two separated levels of functionality are identified in the nanostructure which covers the wings of the grey cicada $\\textit{Cicada orni}$ (Hemiptera). The upper level is responsible for superhydrophobic character of the wing while the lower level enhances its anti-reflective behavior. Extensive wetting experiments with various chemical species and optical measurements were performed in order to assess the bi-functionality. Scanning electron microscopy imaging was used to identify the nanostructure morphology. Numerical optical simulations and analytical wetting models were used to prove the roles of both levels of the nanostructure. In addition, the complex refractive index of the chitinous material of the wing was determined from measurements.

  8. Modeling the absorption behavior of solar thermal collector coatings utilizing graded alpha-C:H/TiC layers.

    Science.gov (United States)

    Gruber, D P; Engel, G; Sormann, H; Schüler, A; Papousek, W

    2009-03-10

    Wavelength selective coatings are of common use in order to enhance the efficiency of devices heated by radiation such as solar thermal collectors. The use of suitable materials and the optimization of coating layer thicknesses are advisable ways to maximize the absorption. Further improvement is achievable by embedding particles in certain layers in order to modify material properties. We focus on optimizing the absorption behavior of a solar collector setup using copper as substrate, a layer of amorphous hydrogenated carbon with embedded titanium carbide particles (a-C:H/TiC), and an antireflection coating of amorphous silicon dioxide (aSiO(2)). For the setup utilizing homogeneous particle distribution, a relative absorption of 90.98% was found, while inhomogeneous particle embedding yielded 98.29%. These results are particularly interesting since until now, absorption of more than 95% was found only by using embedded Cr but not by using the more biocompatible Ti. PMID:19277084

  9. Laser Damage Threshold Increase of A/R Coating Films for 200 MHz AOM

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Y.H.; Lee, H.W.; Lee, J.H.; Park, Y.J.; Park, J.H. [SAMSUNG ADVANCED INSTITUTE OF TECHNOLOHY, TAEJON (Korea, Republic of)

    1997-03-01

    AOM(Acousto-optic modulator)with 200 MHz frequency and SHG(Second harmonic generation)green laser with 532 nm wavelength were used for DVDR(Digital video disk recorder). For the application of high density optical recording, a high power laser is required for the system and optical coating layers of each optical device must have a high laser damage threshold. We made anti-reflective coatings on a TeO{sub 2} single crystal, which is used as an acousto-optic material, by E-beam evaporation method. Laser damage threshold was measured by Ar laser with the input power of 0.55 W. Laser damage threshold of ZrO{sub 2} and SiO{sub 2} films were higher than Al{sub 2}O{sub 3} film. We also investigated a long-term stability of the output power of SHG green laser (author). 6 refs. figs.

  10. Abrasion-resistant solgel antireflective films with a high laser-induced damage threshold for inertial confinement fusion

    Science.gov (United States)

    Xu, Yao; Zhang, Lei; Wu, Dong; Sun, Yu Han; Huang, Zu Xing; Jiang, Xiao Dong; Wei, Xiao Feng; Li, Zhi Hong; Dong, Bao Zhong; Wu, Zhong Hua

    2005-09-01

    To prepare abrasion-resistant antireflective (AR) films for inertial confinement fusion, four solgel routes have been investigated on polysiloxane-modified and polyvinylalcohol- (PVA-) modified SiO2 sols. As confirmed with a transmissive electron microscope, different fractal structure characteristics of the modified SiO2 particles are disclosed by small-angle x-ray scattering technology. And it is these special fractal characteristics that determine the performance of AR films on the level of internal microstructure. A 29Si magic angle spinning and nuclear magnetic resonance study has been successfully applied in explaining the fractal microstructure and its relation to the laser-induced damage threshold (LIDT) of AR films. The films modified by PVA120000 or acetic acid-catalyzed polysiloxane have higher LIDTs than those films modified by PVA16000 or hydrochloride acid-catalyzed polysiloxane. The films from PVA-modified SiO2 sols have a stronger abrasion resistance but lower antireflection than those films from polysiloxane-modified SiO2 sols. In addition, the films from polysiloxane-modified SiO2 sols can possess high transmittance and high LIDT if the polysiloxane synthesis condition is appropriately chosen, but the abrasion resistance is not as good as that from PVA modification. If strong abrasion resistance is necessary, a possible resolution may be to choose a more appropriate hydrophilic polymer than PVA. If not, polysiloxane-modified silica sol can also work when polysiloxane is synthesized under acetic acid catalysis.

  11. Preparation and properties of MgF2 anti-reflective thin film by sol-gel process

    International Nuclear Information System (INIS)

    MgF2 anti-reflective thin films were successfully prepared in methanol media via sol-gel process using magnesium acetate and hydrofluoric acid as reactants. The influence of processing temperature on MgF2 sols was investigated. As-synthesized MgF2 sol was used to deposit AR films on quartz substrate, which could be applied for 355 nm UV laser. The results showed that MgF2 thin films had low refractive index, small surface roughness and good anti-reflective property in the UV region and high la- ser-induced damage threshold (LIDT) at 355 nm (6 ns pulses). The refractive index at 355 nm wavelength of film decreased with the increase of processing temperature. The transmittance and LIDT of quartz substrate with double-side MgF2 films both reached the maximum value, that is, 99.4% for transmittance and 10.85 J·cm-2 (6 ns pulses) for LIDT when the processing temperature was 120 degree C. (authors)

  12. Performance Improvement of GaN-Based Flip-Chip White Light-Emitting Diodes with Diffused Nanorod Reflector and with ZnO Nanorod Antireflection Layer

    Directory of Open Access Journals (Sweden)

    Hsin-Ying Lee

    2014-01-01

    Full Text Available The GaN-based flip-chip white light-emitting diodes (FCWLEDs with diffused ZnO nanorod reflector and with ZnO nanorod antireflection layer were fabricated. The ZnO nanorod array grown using an aqueous solution method was combined with Al metal to form the diffused ZnO nanorod reflector. It could avoid the blue light emitted out from the Mg-doped GaN layer of the FCWLEDs, which caused more blue light emitted out from the sapphire substrate to pump the phosphor. Moreover, the ZnO nanorod array was utilized as the antireflection layer of the FCWLEDs to reduce the total reflection loss. The light output power and the phosphor conversion efficiency of the FCWLEDs with diffused nanorod reflector and 250 nm long ZnO nanorod antireflection layer were improved from 21.15 mW to 23.90 mW and from 77.6% to 80.1% in comparison with the FCWLEDs with diffused nanorod reflector and without ZnO nanorod antireflection layer, respectively.

  13. Optical Properties of Nanostructured Dielectric Coatings

    Science.gov (United States)

    Giatti, Brandon

    Solar cells have extrinsic losses from a variety of sources which can be minimized by optimization of the design and fabrication processes. Reflection from the front surface is one such loss mechanism and has been managed in the past with the usage of planar antireflection coatings. While effective, these coatings are each limited to a single wavelength of light and do not account for varying incident angles of the incoming light source. Three-dimensional nanostructures have shown the ability to inhibit reflection for differing wavelengths and angles of incidence. Nanocones were modeled and show a broadband, multi-angled reflectance decrease due to an effective grading of the index. Finite element models were created to simulate incident light on a zinc oxide nanocone textured silicon substrate. Zinc oxide is advantageous for its ease of production, benign nature, and refractive index matching to the air source region and silicon substrate. Reflectance plots were computed as functions of incident angle and wavelength of light and compared with planar and quintic refractive index profile models. The quintic profile model exhibits nearly optimum reflection minimization and is thus used as a benchmark. Physical quantities, including height, width, density, and orientation were varied in order to minimize the reflectance. A quasi-random nanocone unit cell was modeled to better mimic laboratory results. The model was comprised of 10 nanocones with differing structure and simulated a larger substrate by usage of periodic boundary conditions. The simulated reflectance shows approximately a 50 percent decrease when compared with a planar model. When a seed layer is added, simulating a layer of non-textured zinc oxide, on which the nanocones are grown, the reflectance shows a fourfold decrease when compared with planar models. At angles of incidence higher than 75 degrees, the nanocone model outperformed the quintic model.

  14. Study of barrier coats for application in immersion 193-nm lithography

    Science.gov (United States)

    Houlihan, Francis; Kim, Wookyu; Sakamuri, Raj; Hamilton, Keino; Dimerli, Alla; Abdallah, David; Romano, Andrew; Dammel, Ralph R.; Pawlowski, Georg; Raub, Alex; Brueck, Steve

    2005-05-01

    We will describe our barrier coat approach for use in immersion 193 nm lithography. These barrier coats may act as either simple barriers providing protection against loss of resist components into water or in the case of one type of these formulations which have a refractive index at 193 nm which is the geometric mean between that of the resist and water provide, also top antireflective properties. Either type of barrier coat can be applied with a simple spinning process compatible with PGMEA based resin employing standard solvents such as alcohols and be removed during the usual resist development process with aqueous 0.26 N TMAH. We will discuss both imaging results with these materials on acrylate type 193 nm resists and also show some fundamental studies we have done to understand the function of the barrier coat and the role of differing spinning solvents and resins. We will show LS (55 nm) and Contact Hole (80 nm) resolved with a 193 nm resist exposed with the interferometric tool at the University of New Mexico (213 nm) with and without the use of a barrier coat.

  15. Facile Deposition of Ultrafine Silver Particles on Silicon Surface Not Submerged in Precursor Solutions for Applications in Antireflective Layer

    Directory of Open Access Journals (Sweden)

    Bing Jiang

    2014-01-01

    Full Text Available Using a facile deposition method, the ultrafine silver particles are successfully deposited on the Si surface that is not submerged in precursor solutions. The ultrafine silver particles have many advantages, such as quasiround shape, uniformity in size, monodisperse distribution, and reduction of agglomeration. The internal physical procedure in the deposition is also investigated. The results show that there are more particles on the rough Si surface due to the wetting effect of solid-liquid interface. The higher concentration of ethanol solvent can induce the increase of quantity and size of particles on Si surface not in solutions. The ultrafine particles can be used to prepare porous Si antireflective layer in solar cell applications.

  16. Nanostructures on spin-coated polymer films controlled by solvent composition and polymer molecular weight

    Energy Technology Data Exchange (ETDEWEB)

    Dario, Aline F.; Macia, Henrique B.; Petri, Denise F.S., E-mail: dfsp@iq.usp.br

    2012-12-01

    In this study we systematically investigated how the solvent composition used for polymer dissolution affects the porous structures of spin-coated polymers films. Cellulose acetate butyrate (CAB) and poly(methyl methacrylate) with low (PMMA-L) and high (PMMA-H) molecular weights were dissolved in mixtures of acetone (AC) and ethyl acetate (EA) at constant polymer concentration of 10 g/L The films were spin-coated at a relative air humidity of 55 {+-} 5%, their thickness and index of refraction were determined by means of ellipsometry and their morphology was analyzed by atomic force microscopy. The dimensions and frequency of nanocavities on polymer films increased with the acetone content ({phi}{sub AC}) in the solvent mixture and decreased with increasing polymer molecular weight. Consequently, as the void content increased in the films, their apparent thicknesses increased and their indices of refraction decreased, creating low-cost anti-reflection surface. The void depth was larger for PMMA-L than for CAB. This effect was attributed to different activities of EA and AC in CAB or PMMA-L solution, the larger mobility of chains and the lower polarity of PMMA-L in comparison to CAB. - Highlights: Black-Right-Pointing-Pointer Nanostructures in spin-coated polymer films depend on the solvent vapor pressure. Black-Right-Pointing-Pointer Anti-reflection polymer films are produced at high solvent vapor pressure. Black-Right-Pointing-Pointer Only shallow cavities are obtained in films of polymers with high molecular weight.

  17. Graphene Coatings

    DEFF Research Database (Denmark)

    Stoot, Adam Carsten; Camilli, Luca; Bøggild, Peter

    2014-01-01

    Owing to its remarkable electrical and mechanical properties, graphene has been attracting tremendous interest in materials science. In particular, its chemical stability and impermeability make it a promising protective membrane. However, recent investigations reveal that single layer graphene...... cannot be used as a barrier in the long run, due to galvanic corrosion phenomena arising when oxygen or water penetrate through graphene cracks or domain boundaries. Here, we overcome this issue by using a multilayered (ML) graphene coating. Our lab- as well as industrial-scale tests demonstrate that ML...... graphene can effectively protect Ni in harsh environments, even after long term exposure. This is made possible by the presence of a high number of graphene layers, which can efficiently mask the cracks and domain boundaries defects found in individual layers of graphene. Our findings thus show...

  18. Spectral reflectance data of a high temperature stable solar selective coating based on MoSi2–Si3N4

    Science.gov (United States)

    Hernández-Pinilla, D.; Rodríguez-Palomo, A.; Álvarez-Fraga, L.; Céspedes, E.; Prieto, J.E.; Muñoz-Martín, A.; Prieto, C.

    2016-01-01

    Data of optical performance, thermal stability and ageing are given for solar selective coatings (SSC) based on a novel MoSi2–Si3N4 absorbing composite. SSC have been prepared as multilayer stacks formed by silver as metallic infrared reflector, a double layer composite and an antireflective layer (doi: 10.1016/j.solmat.2016.04.001 [1]). Spectroscopic reflectance data corresponding to the optical performance of samples after moderate vacuum annealing at temperatures up to 600 °C and after ageing test of more than 200 h with several heating–cooling cycles are shown here. PMID:27182544

  19. Spectral reflectance data of a high temperature stable solar selective coating based on MoSi2 -Si3N4.

    Science.gov (United States)

    Hernández-Pinilla, D; Rodríguez-Palomo, A; Álvarez-Fraga, L; Céspedes, E; Prieto, J E; Muñoz-Martín, A; Prieto, C

    2016-06-01

    Data of optical performance, thermal stability and ageing are given for solar selective coatings (SSC) based on a novel MoSi2-Si3N4 absorbing composite. SSC have been prepared as multilayer stacks formed by silver as metallic infrared reflector, a double layer composite and an antireflective layer (doi: 10.1016/j.solmat.2016.04.001 [1]). Spectroscopic reflectance data corresponding to the optical performance of samples after moderate vacuum annealing at temperatures up to 600 °C and after ageing test of more than 200 h with several heating-cooling cycles are shown here. PMID:27182544

  20. Spectral reflectance data of a high temperature stable solar selective coating based on MoSi2–Si3N4

    Directory of Open Access Journals (Sweden)

    D. Hernández-Pinilla

    2016-06-01

    Full Text Available Data of optical performance, thermal stability and ageing are given for solar selective coatings (SSC based on a novel MoSi2–Si3N4 absorbing composite. SSC have been prepared as multilayer stacks formed by silver as metallic infrared reflector, a double layer composite and an antireflective layer (doi: 10.1016/j.solmat.2016.04.001 [1]. Spectroscopic reflectance data corresponding to the optical performance of samples after moderate vacuum annealing at temperatures up to 600 °C and after ageing test of more than 200 h with several heating–cooling cycles are shown here.

  1. Electrocurtain coating process for coating solar mirrors

    Science.gov (United States)

    Kabagambe, Benjamin; Boyd, Donald W.; Buchanan, Michael J.; Kelly, Patrick; Kutilek, Luke A.; McCamy, James W.; McPheron, Douglas A.; Orosz, Gary R.; Limbacher, Raymond D.

    2013-10-15

    An electrically conductive protective coating or film is provided over the surface of a reflective coating of a solar mirror by flowing or directing a cation containing liquid and an anion containing liquid onto the conductive surface. The cation and the anion containing liquids are spaced from, and preferably out of contact with one another on the surface of the reflective coating as an electric current is moved through the anion containing liquid, the conductive surface between the liquids and the cation containing liquid to coat the conductive surface with the electrically conductive coating.

  2. Antireflective sub-wavelength structures for improvement of the extraction efficiency and color rendering index of monolithic white light-emitting diode

    OpenAIRE

    Ou, Yiyu; Corell, Dennis Dan; Dam-Hansen, Carsten; Petersen, Paul Michael; Ou, Haiyan

    2011-01-01

    We have theoretically investigated the influence of antireflective sub-wavelength structures on a monolithic white light-emitting diode (LED). The simulation is based on the rigorous coupled wave analysis (RCWA) algorithm, and both cylinder and moth-eye structures have been studied in the work. Our simulation results show that a moth-eye structure enhances the light extraction efficiency over the entire visible light range with an extraction efficiency enhancement of up to 26 %. Also for the ...

  3. Hydrothermal Synthesis Au-Bi2Te3 Nanocomposite Thermoelectric Film with a Hierarchical Sub-Micron Antireflection Quasi-Periodic Structure

    OpenAIRE

    Junlong Tian; Wang Zhang; Yuan Zhang; Ruiyang Xue; Yuhua Wang; Zhijian Zhang; Di Zhang

    2015-01-01

    In this work, Au-Bi2Te3 nanocomposite thermoelectric film with a hierarchical sub-micron antireflection quasi-periodic structure was synthesized via a low-temperature chemical route using Troides helena (Linnaeus) forewing (T_FW) as the biomimetic template. This method combines chemosynthesis with biomimetic techniques, without the requirement of expensive equipment and energy intensive processes. The microstructure and the morphology of the Au-Bi2Te3 nanocomposite thermoelectric film was ana...

  4. Growth of TiO2 anti-reflection layer on textured Si (100) wafer substrate by metal-organic chemical vapor deposition method.

    Science.gov (United States)

    Nam, Sang-Hun; Choi, Jin-Woo; Cho, Sang-Jin; Kimt, Keun Soo; Boo, Jin-Hyo

    2011-08-01

    Recently anti-reflective films (AR) have been intensely studied. Particularly for textured silicon solar cells, the AR films can further reduce the reflection of the incident light through trapping the incident light into the cells. In this work, TiO2 anti-reflection films have been grown on the textured Si (100) substrate which is processed in two steps, and the films are deposited using metal-organic chemical vapor deposition (MOCVD) with a precursor of titanium tetra-isopropoxide (TTIP). The effect of the substrate texture and the growth conditions of TiO2 films on the reflectance has been investigated. Pyramid size of textured silicon had approximately 2-9 microm. A well-textured silicon surface can lower the reflectance to 10%. For more reduced reflection, TiO2 anti-reflection films on the textured silicon were deposited at 600 degrees C using titanium tetra-isopropoxide (TTIP) as a precursor by metal-organic chemical vapor deposition (MOCVD), and the deposited TiO2 layers were then treated by annealing for 2 h in air at 600 and 1000 degrees C, respectively. In this process, the treated samples by annealing showed anatase and rutile phases, respectively. The thickness of TiO2 films was about 75 +/- 5 nm. The reflectance at specific wavelength can be reduced to 3% in optimum layer. PMID:22103185

  5. Fabrication and optical properties of sol-gel-derived interference coating for high power laser applications

    Science.gov (United States)

    Zhang, Qinyuan; Pita, Kantisara; Xu, Chang-Qing; Que, Wenxiu; Hinooda, S.; Thilakan, Periyasamy

    2001-10-01

    A single layer sol-gel derived TiO2 thin films and 6 periods SiO2/TiO2 multilayer coating were designed and prepared on GaAs substrates as anti-reflection coating or near-IR-reflective coating for high power semiconductor laser applications. Crack free TiO2 thin films having thickness of 80-150 nm, and refractive indices of 1.8-2.1 have been obtained by simply sol-gel method upon heating at different temperatures. The obtained TiO2 thin films on GaAs substrates have shown reflectance of EQ 1 percent in the wavelength of about 808 nm. Thin films of TiO2 and SiO2 were also used to fabricate near IR reflector ion GaAs substrates. The reflector consisted of 6 SiO2/TiO2 bi-layers, designed with a high-reflective band in the wavelength of 1064 nm. A minimum transmittance of EQ 2 percent in the wavelength range between 950 and 1100 nm has been obtained in the present multilayer SiO2/TiO2 coating.

  6. Development of selective surfaces. Semiannual technical progress report, September 11, 1978-April 30, 1979. [Multilayer coatings

    Energy Technology Data Exchange (ETDEWEB)

    Thornton, J.A.

    1979-06-15

    Magnetron sputtering technology, which permits coatings to be deposited over large areas with significantly increased deposition rates, is reviewed with particular emphasis on cylindrical magnetrons and their application to reactive sputtering. Work is reported in which cylindrical-post magnetron sputtering sources have been used to deposit both graded and multi-layered cermet-type coatings by sputtering chromium and type 304 stainless steel in Ar and O/sub 2/ and Ar and CO gas mixtures under various conditions of reactive gas injection. The substrates are aluminum-coated glass and aluminum foil. The coatings are of an interference type, typically about 100 nm thick, with a metal-rich, highly absorbing layer adjacent to the substrate and a dielectric material at the surface. In some cases a reactively sputtered aluminum oxide anti-reflective surface layer has also been used. No advantages have been found for using chromium as opposed to the more readily available stainless steel. The reactive sputtering with CO is attractive because under many conditions the sputtering rates are relatively large compared to oxygen. Hemispherical absorptance and emittance data are reported. Typical absorptances are about 0.90 with emittances of 0.10.

  7. Laser damage of HR, AR-coatings, monolayers and bare surfaces at 1064 nm

    Science.gov (United States)

    Garnov, S. V.; Klimentov, S. M.; Said, A. A.; Soileau, M. J.

    1993-01-01

    Laser induced damage thresholds and morphologies were investigated in a variety of uncoated and coated surfaces, including monolayers and multi-layers of different chemical compositions. Both antireflective (AR) and highly reflective (HR) were tested. Testing was done at 1064 nm with 25 picosecond and 8 nanosecond YAG/Nd laser single pulses. Spot diameter in the experiments varied from 0.09 to 0.22 mm. The laser damage measurement procedure consisted of 1-on-1 (single laser pulse in the selected site) and N-on-1 experiments including repeated irradiation by pulses of the same fluence and subsequently raised from pulse to pulse fluence until damage occurred. The highest picosecond damage thresholds of commercially available coatings averaged 12 - 14 J/sq cm, 50 percent less than thresholds obtained in bare fused silica. Some coatings and bare surfaces revealed a palpable preconditioning effect (an increase in threshold of 1.2 to 1.8 times). Picosecond and nanosecond data were compared to draw conclusions about pulse width dependence. An attempt was made to classify damage morphologies according to the type of coating, class of irradiating, and damage level.

  8. Flow coating apparatus and method of coating

    Science.gov (United States)

    Hanumanthu, Ramasubrahmaniam; Neyman, Patrick; MacDonald, Niles; Brophy, Brenor; Kopczynski, Kevin; Nair, Wood

    2014-03-11

    Disclosed is a flow coating apparatus, comprising a slot that can dispense a coating material in an approximately uniform manner along a distribution blade that increases uniformity by means of surface tension and transfers the uniform flow of coating material onto an inclined substrate such as for example glass, solar panels, windows or part of an electronic display. Also disclosed is a method of flow coating a substrate using the apparatus such that the substrate is positioned correctly relative to the distribution blade, a pre-wetting step is completed where both the blade and substrate are completed wetted with a pre-wet solution prior to dispensing of the coating material onto the distribution blade from the slot and hence onto the substrate. Thereafter the substrate is removed from the distribution blade and allowed to dry, thereby forming a coating.

  9. SiC protective coating for photovoltaic retinal prosthesis

    Science.gov (United States)

    Lei, Xin; Kane, Sheryl; Cogan, Stuart; Lorach, Henri; Galambos, Ludwig; Huie, Philip; Mathieson, Keith; Kamins, Theodore; Harris, James; Palanker, Daniel

    2016-08-01

    Objective. To evaluate plasma-enhanced, chemically vapor deposited (PECVD) amorphous silicon carbide (α-SiC:H) as a protective coating for retinal prostheses and other implantable devices, and to study their failure mechanisms in vivo. Approach. Retinal prostheses were implanted in rats sub-retinally for up to 1 year. Degradation of implants was characterized by optical and scanning electron microscopy. Dissolution rates of SiC, SiN x and thermal SiO2 were measured in accelerated soaking tests in saline at 87 °C. Defects in SiC films were revealed and analyzed by selectively removing the materials underneath those defects. Main results. At 87 °C SiN x dissolved at 18.3 ± 0.3 nm d‑1, while SiO2 grown at high temperature (1000 °C) dissolved at 0.104 ± 0.008 nm d‑1. SiC films demonstrated the best stability, with no quantifiable change after 112 d. Defects in thin SiC films appeared primarily over complicated topography and rough surfaces. Significance. SiC coatings demonstrating no erosion in accelerated aging test for 112 d at 87 °C, equivalent to about 10 years in vivo, can offer effective protection of the implants. Photovoltaic retinal prostheses with PECVD SiC coatings exhibited effective protection from erosion during the 4 month follow-up in vivo. The optimal thickness of SiC layers is about 560 nm, as defined by anti-reflective properties and by sufficient coverage to eliminate defects.

  10. Characterisation Studies of the Structure and Properties of As-Deposited and Annealed Pulsed Magnetron Sputtered Titania Coatings

    Directory of Open Access Journals (Sweden)

    John A. Ridealgh

    2013-09-01

    Full Text Available Titanium dioxide thin films are durable, chemically stable, have a high refractive index and good electro/photochemical proprieties. Consequently, they are widely used as anti-reflective layers in optical devices and large area glazing products, dielectric layers in microelectronic devices and photo catalytic layers in self-cleaning surfaces. Titania coatings may have amorphous or crystalline structures, where three crystalline phases of TiO2 can be obtained: anatase, rutile and brookite, although the latter is rarely found. It is known, however, that the structure of TiO2 coatings is sensitive to deposition conditions and can also be modified by post-deposition heat treatments. In this study, titania coatings have been deposited onto soda-lime glass substrates by reactive sputtering from a metallic target. The magnetron was driven in mid-frequency pulsed DC mode. The as-deposited coatings were analysed by micro Raman spectroscopy, X-ray diffraction (XRD, atomic force microscopy (AFM and scanning electron microscopy (SEM. Selected coatings were annealed at temperatures in the range 200–700 °C and re-analysed. Whilst there was weak evidence of a nanocrystallinity in the as-deposited films, it was observed that these largely amorphous low temperature structures converted into strongly crystalline structures at annealing temperatures above 400 °C.

  11. European coatings conference - Marine coatings. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    This volume contains 13 lectures (manuscripts or powerpoint foils) with the following topics: 1. Impact of containerization on polyurethane and polyurea in marine and protective coatings (Malte Homann); 2. The application of combinatorial/high-throughput methods to the development of marine coatings (Bret Chisholm); 3. Progress and perspectives in the AMBIO (advanced nanostructured surfaces for the control of biofouling) Project (James Callow); 4. Release behaviour due to shear and pull-off of silicone coatings with a thickness gradient (James G. Kohl); 5. New liquid rheology additives for high build marine coatings (Andreas Freytag); 6. Effective corrosion protection with polyaniline, polpyrrole and polythiophene as anticorrosice additives for marine paints (Carlos Aleman); 7. Potential applications of sol gel technology for marine applications (Robert Akid); 8: Performance of biocide-free Antifouling Coatings for leisure boats (Bernd Daehne); 9. Novel biocidefree nanostructured antifouling coatings - can nano do the job? (Corne Rentrop); 10. One component high solids, VOC compliant high durability finish technology (Adrian Andrews); 11. High solid coatings - the hybrid solution (Luca Prezzi); 12. Unique organofunctional silicone resins for environmentally friendly high-performance coatings (Dieter Heldmann); 13. Silicone-alkyd paints for marine applications: from battleship-grey to green (Thomas Easton).

  12. Corrosion inhibiting organic coatings

    Energy Technology Data Exchange (ETDEWEB)

    Sasson, E.

    1984-10-16

    A corrosion inhibiting coating comprises a mixture of waxes, petroleum jelly, a hardener and a solvent. In particular, a corrosion inhibiting coating comprises candelilla wax, carnauba wax, microcrystalline waxes, white petrolatum, an oleoresin, lanolin and a solvent.

  13. Forming the graded-refractive-index antireflection layers on light-emitting diodes to enhance the light extraction.

    Science.gov (United States)

    Cho, Joong-Yeon; Byeon, Kyeong-Jae; Lee, Heon

    2011-08-15

    Distributed antireflection (AR) layers with different composition ratios of ITO and SiO(2) formed on an ITO electrode of GaN-based LEDs provide substantial enhancement in light-extraction efficiency. By using the coradio frequency magnetron sputtering deposition, four 50 nm thick AR layers with graduated refractive indices were fabricated. The effect of the AR layers on enhancing the efficiency of the LED device was analyzed by electroluminescence (EL) and I-V measurements. As a result, the EL intensity of the LED device grown on the patterned sapphire substrate with AR layers was increased by up to 13% compared to the conventional patterned sapphire substrate-applied LED device without AR layers at a drive current of 20 mA. The AR layers on top of the LED device gradually changed the refractive indices between ITO (n=2.1) and air (n=1.0), which minimized the total internal reflection of generated light. And no degradation in the electrical characteristic of the LEDs was observed according to the I-V measurements. PMID:21847208

  14. Coatings: Pt. 4

    International Nuclear Information System (INIS)

    The demands imposed on the coating industry to reduce environmental pollution and energy consumption and to produce high quality coatings in an era where the cost of raw materials increases continuously, have stimulated interest and research in radiation curing methods for coatings. Radiation such as ionising radiation, visible light, infra red and micro waves can be applied. In this article attention is given to electron beam curing and special reference is made to modern wood coating equipment

  15. PIT Coating Requirements Analysis

    Energy Technology Data Exchange (ETDEWEB)

    MINTEER, D.J.

    2000-10-20

    This study identifies the applicable requirements for procurement and installation of a coating intended for tank farm valve and pump pit interior surfaces. These requirements are intended to be incorporated into project specification documents and design media. This study also evaluates previously recommended coatings and identifies requirement-compliant coating products.

  16. PIT Coating Requirements Analysis

    International Nuclear Information System (INIS)

    This study identifies the applicable requirements for procurement and installation of a coating intended for tank farm valve and pump pit interior surfaces. These requirements are intended to be incorporated into project specification documents and design media. This study also evaluates previously recommended coatings and identifies requirement-compliant coating products

  17. Fuel particle coating data

    International Nuclear Information System (INIS)

    Development of coating on nuclear fuel particles for the High-Temperature Fuels Technology program at the Los Alamos Scientific Laboratory included process studies for low-density porous and high-density isotropic carbon coats, and for ZrC and ''alloy'' C/ZrC coats. This report documents the data generated by these studies

  18. Ceramic with zircon coating

    Science.gov (United States)

    Wang, Hongyu (Inventor)

    2003-01-01

    An article comprises a silicon-containing substrate and a zircon coating. The article can comprise a silicon carbide/silicon (SiC/Si) substrate, a zircon (ZrSiO.sub.4) intermediate coating and an external environmental/thermal barrier coating.

  19. Optical Properties of Window Coatings

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Window coating used for the building in recent years is described. Important design principles, practical coating materials, and attainable optical properties for research-type coatings are introduced. Discussion is carried out on the spectrally selective coatings, the electrochromic coatings, and the thermochromic coatings.

  20. Antibacterial polymer coatings.

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Mollye C.; Allen, Ashley N.; Barnhart, Meghan; Tucker, Mark David; Hibbs, Michael R.

    2009-09-01

    A series of poly(sulfone)s with quaternary ammonium groups and another series with aldehyde groups are synthesized and tested for biocidal activity against vegetative bacteria and spores, respectively. The polymers are sprayed onto substrates as coatings which are then exposed to aqueous suspensions of organisms. The coatings are inherently biocidal and do not release any agents into the environment. The coatings adhere well to both glass and CARC-coated coupons and they exhibit significant biotoxicity. The most effective quaternary ammonium polymers kills 99.9% of both gram negative and gram positive bacteria and the best aldehyde coating kills 81% of the spores on its surface.

  1. Metallic coating of microspheres

    International Nuclear Information System (INIS)

    Extremely smooth, uniform metal coatings of micrometer thicknesses on microscopic glass spheres (microspheres) are often needed as targets for inertial confinement fusion (ICF) experiments. The first part of this paper reviews those methods used successfully to provide metal coated microspheres for ICF targets, including magnetron sputtering, electro- and electroless plating, and chemical vapor pyrolysis. The second part of this paper discusses some of the critical aspects of magnetron sputter coating of microspheres, including substrate requirements, the sticking of microspheres during coating (preventing a uniform coating), and the difficulties in growing the desired dense, smooth, uniform microstructure on continuously moving spherical substrates

  2. ATHENA optimized coating design

    DEFF Research Database (Denmark)

    Ferreira, Desiree Della Monica; Christensen, Finn Erland; Jakobsen, Anders Clemen;

    2012-01-01

    The optimization of coating design for the ATHENA mission si described and the possibility of increasing the telescope effective area in the range between 0.1 and 10 keV is investigated. An independent computation of the on-axis effective area based on the mirror design of ATHENA is performed in...... order to review the current coating baseline. The performance of several material combinations, considering a simple bi-layer, simple multilayer and linear graded multilayer coatings are tested and simulation of the mirror performance considering both the optimized coating design and the coating...

  3. Anticorrosive coatings: a review

    DEFF Research Database (Denmark)

    Sørensen, Per Aggerholm; Kiil, Søren; Dam-Johansen, Kim;

    2009-01-01

    The main objective of this review is to describe some of the important topics related to the use of marine and protective coatings for anticorrosive purposes. In this context, "protective" refers to coatings for containers, offshore constructions, wind turbines, storage tanks, bridges, rail cars......, and petrochemical plants while "marine" refers to coatings for ballast tanks, cargo holds and cargo tanks, decks, and engine rooms on ships. The review aims at providing a thorough picture of state-of-the-art in anticorrosive coatings systems. International and national legislation aiming at reducing...... the emission of volatile organic compounds (VOCs) have caused significant changes in the anticorrosive coating industry. The requirement for new VOC-compliant coating technologies means that coating manufacturers can no longer rely on the extensive track record of their time-served products to...

  4. Coated Aerogel Beads

    Science.gov (United States)

    Littman, Howard (Inventor); Plawsky, Joel L. (Inventor); Paccione, John D. (Inventor)

    2014-01-01

    Methods and apparatus for coating particulate material are provided. The apparatus includes a vessel having a top and a bottom, a vertically extending conduit having an inlet in the vessel and an outlet outside of the vessel, a first fluid inlet in the bottom of the vessel for introducing a transfer fluid, a second fluid inlet in the bottom of the vessel for introducing a coating fluid, and a fluid outlet from the vessel. The method includes steps of agitating a material, contacting the material with a coating material, and drying the coating material to produce a coated material. The invention may be adapted to coat aerogel beads, among other materials. A coated aerogel bead and an aerogel-based insulation material are also disclosed.

  5. Alleviation of process-induced cracking of the antireflection TiN coating (ARC-TiN) in Al-Cu and Al-Cu-Si films

    CERN Document Server

    Peng, Y C; Yang, Y R; Hsieh, W Y; Hsieh, Y F

    1999-01-01

    The alleviation of cracking of the TiN-ARC layer on Al-Cu and Al-Cu-Si films after the development process has been achieved. For the TiN-ARC/Al-Cu system, the stress-induced defects decreased with increasing TiN-ARC layer thickness. In contrast, for the TiN-ARC/Al-Cu-Si system, Si nodules formed during cooling, thereby inducing poor coverage with high aspect-ratio holes. As a result, the photoresist developer penetrated through the films. Chemical vapor deposition of TiN-ARC or predeposition of a Ti Interposing layer was used to eliminate the formation of Si nodules.

  6. Design and fabrication of anti-reflection coating on Gallium Phosphide, Zinc Selenide and Zinc Sulfide substrates for visible and infrared application

    Czech Academy of Sciences Publication Activity Database

    Vápenka, David; Václavík, Jan; Mokrý, Pavel

    Cedex: EDP Sciences, 2013 - (Šulc, M.; Kopecký, V.; Lédl, V.; Melich, R.; Skeren, M.), s. 00029. (Book Series: EPJ Web of Conferences. 48). ISSN 2100-014X. [OaM 2012 International Conference on Optics and Measurement. Liberec (CZ), 16.10.2012-18.10.2012] R&D Projects: GA MŠk(CZ) OE10003; GA MŠk(CZ) ED2.1.00/03.0079 Institutional support: RVO:61389021 Keywords : gallium phosphide * zinc selenide * zinc sulfide Subject RIV: JK - Corrosion ; Surface Treatment of Materials http://www.epj-conferences.org/articles/epjconf/pdf/2013/09/epjconf_OAM2012_00029.pdf

  7. Design and Manufacture of Broadband Infrared Antireflection Coatings for Germanium Windows%锗窗口红外宽光谱增透膜的研制

    Institute of Scientific and Technical Information of China (English)

    于天燕; 成效春; 秦杨; 刘定权; 张凤山

    2010-01-01

    红外宽光谱增透膜作为红外光学系统中的关键元件,其研究是一项比较复杂而备受重视的工作.针对风云二号辐射计锗窗口的宽光谱增透膜的要求,通过对镀膜材料在既定工艺条件下的光学参数的准确拟合,采用非对称等效层理论,并将材料光学参数拟合值代入到膜系的优化过程中,从而得到能够与实际情况接近的理论设计膜系.经过工艺优化后,研制出的宽光谱增透膜在要求的3.5~4.0μm,6.3~7.6 μm,10.3~11.μm三个通道的平均透射率均大于96%,而11.5~12.5μm通道的平均透射率大于94%.膜层能够经受住浸泡、高温高湿等一系列环模试验的检验,完全满足项目的使用要求.

  8. Alleviation of process-induced cracking of the antireflection TiN coating (ARC-TiN) in Al-Cu and Al-Cu-Si films

    International Nuclear Information System (INIS)

    The alleviation of cracking of the TiN-ARC layer on Al-Cu and Al-Cu-Si films after the development process has been achieved. For the TiN-ARC/Al-Cu system, the stress-induced defects decreased with increasing TiN-ARC layer thickness. In contrast, for the TiN-ARC/Al-Cu-Si system, Si nodules formed during cooling, thereby inducing poor coverage with high aspect-ratio holes. As a result, the photoresist developer penetrated through the films. Chemical vapor deposition of TiN-ARC or predeposition of a Ti Interposing layer was used to eliminate the formation of Si nodules

  9. Peculiarities of the capacitance-voltage characteristic of a photoelectric solar energy convertor based on a silicon p- n junction with a porous silicon antireflection coating

    Science.gov (United States)

    Tregulov, V. V.

    2014-09-01

    Experimental results on the high-frequency capacitance-voltage characteristic of a photoelectric solar energy converter based on the n +- p junction with a thin porous silicon film on the frontal surface are considered. It is shown that the capacitance-voltage characteristic is determined by the surface metal-insulator-semiconductor (MIS) structure formed as a result of growing of a porous silicon layer by electrochemical anode etching. The effective thickness of the insulator layer of the MIS structure, the impurity concentration in its semiconductor region, and the density of surface states are determined.

  10. Fabrication of High Transparency Diamond-Like Carbon Film Coating on D263T Glass at Room Temperature as an Antireflection Layer

    Directory of Open Access Journals (Sweden)

    Chii-Ruey Lin

    2013-01-01

    Full Text Available This study intends to deposit high transmittance diamond-like carbon (DLC thin films on D263T glass substrate at room temperature via a diamond powder target using the radio frequency (RF magnetron sputtering technique. Moreover, various process parameters were used to tune the properties of the thin films by using the Taguchi method. Experimental results show that the content of sp3 bonded carbon decreases in accordance with the effect of the substrate temperature. In addition, the hardness of all as-deposited single-layer DLC films ranges from 13.2 to 22.5 GPa, and the RMS surface roughness was improved significantly with the decrease in sputtering pressure. The water repellent of the deposited DLC films improved significantly with the increase of the sp3 content, and its contact angle was larger than that of the noncoated one by 1.45 times. Furthermore, the refraction index (n of all as-deposited DLC films ranges from 1.95 to 2.1 at λ = 600 nm. These results demonstrate that the thickness increased as the reflectance increased. DLC film under an RF power of 150 W possesses high transmissive ability (>81% and low average reflectance ability (<9.5% in the visible wavelengths (at λ = 400–700 nm.

  11. Evaluation of a new photoresist dispense system to detect coating variation

    Science.gov (United States)

    Gapin, Florent; Le-Peutrec, Bernard; Stock, Laurent; Hanotte, Marc

    2009-03-01

    A minimal change of dispensed volume will have a severe impact on the film thickness uniformity and in the worst case there might be some lack of resist on the wafer. Therefore it is essential to set-up the photoresist dispense accurately to avoid any dispense variation. In addition, it is important to monitor the dispense conditions real-time to detect problems which may have a direct negative impact on process yield. This paper presents the evaluation of the IntelliGen® Mini dispense system which is manufactured by Entegris, Inc. This new system is able to detect variations like bubbles in the dispense line, changes to the stop suckback valve, and changes in viscosity1. After an explanation of the pump characteristics and the potential root causes of dispense variation and their consequences, the evaluation done in Altis Semiconductor will be presented. The study has been made utilizing different photo-chemicals, including low and mid-range viscosity photo- resists and anti-reflective coatings. The capability of this new product to detect any perturbation of coating will be demonstrated. Then standard tests like coating repeatability, defect density CD uniformity and finally wafer yield inspection will be performed to prove efficiency of the system in a production mode.

  12. Energy-saving spectrally-selective coatings based on MoO3/Ag thin films

    International Nuclear Information System (INIS)

    Graphical abstract: Transparent heat mirrors are multilayer structures that transmit light and reflect infrared radiation, thus conserving energy. In this work, this was achieved by deposition of molybdenum oxide thin films on top of silver layers. The silver layer provides the desired high infrared reflectance. The MoO3 thin film is a dielectric material characterized by wide band gap and high refractive index. It works as an antireflective layer, and thus provides the necessary high visible transparency. - Highlights: • Transparent heat mirrors transmit light and reflect infrared heat. • In this work, they were deposited using MoO3/Ag multilayer coatings. • The MoO3 films were smooth, had high refractive index, and wide bandgap. • The fabricated heat mirrors had high visible transparency and infrared reflection. - Abstract: Transparent heat mirrors are spectrally selective coatings that transmit light and reflect heat in the form of infrared radiation. In this work, these coatings were achieved by depositing a two-layer structure consisting of molybdenum oxide thin films deposited on silver thin films by thermal evaporation. First, the structural, chemical, and optical properties of molybdenum oxide thin films, that are relevant to their use in transparent heat mirrors, were investigated. Then, the optical properties of the two-layer structure were determined. Moreover, chemical depth profiling was carried out to investigate the spatial distribution of the elements among the layers. The deposited heat mirrors were found to exhibit the desired behavior of high visible transparency and high infrared reflection

  13. Effect of SiO2 coating in bolometric Ge light detectors for rare event searches

    CERN Document Server

    Beeman, J W; Giuliani, A; Mancuso, M; Pessina, G; Plantevin, O; Rusconi, C

    2012-01-01

    In germanium-based light detectors for scintillating bolometers, a SiO$_2$ anti-reflective coating is often applied on the side of the germanium wafer exposed to light with the aim to improve its light collection efficiency. In this paper, we report about a measurement, performed in the temperature range 25-35 mK, of the light-collection increase obtained thanks to this method, which resulted to be of the order of 20%. The procedure followed has been carefully selected in order to minimize systematic effects. The employed light sources have the same spectral features (peaking at $\\sim 630$ nm wavelength) that will characterise future neutrinoless double beta decay experiments on the isotope $^{82}$Se and based on ZnSe crystals, such as LUCIFER. The coupling between source and light detector reproduces the configuration used in scintillating bolometers. The present measurement clarifies the role of SiO$_2$ coating and describes a method and a set-up that can be extended to the study of other types of coatings ...

  14. Effect of SiO2 coating in bolometric Ge light detectors for rare event searches

    Science.gov (United States)

    Beeman, J. W.; Gentils, A.; Giuliani, A.; Mancuso, M.; Pessina, G.; Plantevin, O.; Rusconi, C.

    2013-05-01

    In germanium-based light detectors for scintillating bolometers, a SiO2 anti-reflective coating is often applied on the side of the germanium wafer exposed to light with the aim to improve its light collection efficiency. In this paper, we report about a measurement, performed in the temperature range 25-35 mK, of the light-collection increase obtained thanks to this method, which resulted to be of the order of 20%. The procedure followed has been carefully selected in order to minimize systematic effects. The employed light sources have the same spectral features (peaking at ˜630 nm wavelength) that will characterize future neutrinoless double beta decay experiments on the isotope 82Se and based on ZnSe crystals, such as LUCIFER. The coupling between source and light detector reproduces the configuration used in scintillating bolometers. The present measurement clarifies the role of SiO2 coating and describes a method and a set-up that can be extended to the study of other types of coatings and luminescent materials.

  15. Effect of SiO2 coating in bolometric Ge light detectors for rare event searches

    International Nuclear Information System (INIS)

    In germanium-based light detectors for scintillating bolometers, a SiO2 anti-reflective coating is often applied on the side of the germanium wafer exposed to light with the aim to improve its light collection efficiency. In this paper, we report about a measurement, performed in the temperature range 25–35 mK, of the light-collection increase obtained thanks to this method, which resulted to be of the order of 20%. The procedure followed has been carefully selected in order to minimize systematic effects. The employed light sources have the same spectral features (peaking at ∼630nm wavelength) that will characterize future neutrinoless double beta decay experiments on the isotope 82Se and based on ZnSe crystals, such as LUCIFER. The coupling between source and light detector reproduces the configuration used in scintillating bolometers. The present measurement clarifies the role of SiO2 coating and describes a method and a set-up that can be extended to the study of other types of coatings and luminescent materials

  16. Combustion chemical vapor desposited coatings for thermal barrier coating systems

    Energy Technology Data Exchange (ETDEWEB)

    Hampikian, J.M.; Carter, W.B. [Georgia Institute of Technology, Atlanta, GA (United States)

    1995-10-01

    The new deposition process, combustion chemical vapor deposition, shows a great deal of promise in the area of thermal barrier coating systems. This technique produces dense, adherent coatings, and does not require a reaction chamber. Coatings can therefore be applied in the open atmosphere. The process is potentially suitable for producing high quality CVD coatings for use as interlayers between the bond coat and thermal barrier coating, and/or as overlayers, on top of thermal barrier coatings.

  17. Electrochemically controlled fabrication of lightly doped porous Si nanowire arrays with excellent antireflective and self-cleaning properties

    International Nuclear Information System (INIS)

    The doping level and morphology of porous Si nanowire (SiNW) arrays are critical for their electrical, optical and surface properties, but preparation of lightly doped porous SiNW arrays with uniform length still remains a challenge. By integrating electroless chemical etching with a proposed electrochemical route, lightly doped single-crystalline porous SiNW arrays with uniform length were prepared from Si wafers with resistivity of 1–770 Ω cm for the first time. Scanning electron microscopy and transmission electron microscopy images show that the size of pores in the NWs is enlarged by increasing the duration of electrochemical process. Based on current–voltage measurements, thermionic emission is proposed to be responsible for the pore formation mechanism. The photoluminescence spectrum of the porous SiNWs shows an obvious peak centered at 680 nm, which is attributed to the quantum confinement effect due to porous structures, evidenced by the shift of Raman peak from 520.7 to 519.7 cm−1. Reflectivity spectra show the average reflectivity of SiNW arrays after electrochemical treatments was further decreased to less than 1.8% in the 350–600 nm wavelength range. Contact angle measurements show that the porous SiNW arrays possess superhydrophobic characteristics with a contact angle of up to 164°. Compared with previous studies, the proposed integrated route can not only prepare uniform, lightly doped, and porous SiNW arrays, but also provide an efficient way to independently control the lengths of NWs and sizes of nanopores in them. The SiNW arrays can be employed as an excellent antireflective and self-cleaning substrate for high efficiency opto-electronic devices.

  18. Optimization of Al2O3/SiNx stacked antireflection structures for N-type surface-passivated crystalline silicon solar cells

    International Nuclear Information System (INIS)

    In the case of N-type solar cells, the anti-reflection property, as one of the important factors to further improve the energy-conversion efficiency, has been optimized using a stacked Al2O3/SiNx layer. The effect of SiNx layer thickness on the surface reflection property was systematically studied in terms of both experimental and theoretical measurement. In the stacked Al2O3/SiNx layers, results demonstrated that the surface reflection property can be effectively optimized by adding a SiNx layer, leading to the improvement in the final photovoltaic characteristic of the N-type solar cells. (semiconductor devices)

  19. Performance Improvement of GaN-Based Flip-Chip White Light-Emitting Diodes with Diffused Nanorod Reflector and with ZnO Nanorod Antireflection Layer

    OpenAIRE

    2014-01-01

    The GaN-based flip-chip white light-emitting diodes (FCWLEDs) with diffused ZnO nanorod reflector and with ZnO nanorod antireflection layer were fabricated. The ZnO nanorod array grown using an aqueous solution method was combined with Al metal to form the diffused ZnO nanorod reflector. It could avoid the blue light emitted out from the Mg-doped GaN layer of the FCWLEDs, which caused more blue light emitted out from the sapphire substrate to pump the phosphor. Moreover, the ZnO nanorod array...

  20. Infrared-induced variation of the magnetic properties of a magnetoplasmonic film with a 3D sub-micron periodic triangular roof-type antireflection structure

    OpenAIRE

    Junlong Tian; Wang Zhang; Yiqiao Huang; Qinglei Liu; Yuhua Wang; Zhijian Zhang; Di Zhang

    2015-01-01

    A carbon-matrix nickel composite magnetoplasmonic film with a 3D sub-micron periodic triangular roof-type antireflection structure (SPTAS) was fabricated via a simple and promising method that combines chemosynthesis with biomimetic techniques. The Troides helena (Linnaeus) forewing (T_FW) was chosen as the biomimetic template. The carbon-matrix Ni wing fabricated via electroless Ni deposition for 6 h (CNMF_6h) exhibits enhanced infrared absorption. Over a wavelength range (888–2500 nm), the ...

  1. Preliminary coating design and coating developments for ATHENA

    DEFF Research Database (Denmark)

    Jakobsen, Anders Clemen; Ferreira, Desiree Della Monica; Christensen, Finn Erland;

    2011-01-01

    We present initial novel coating design for ATHENA. We make use of both simple bilayer coatings of Ir and B4C and more complex constant period multilayer coatings to enhance the effective area and cover the energy range from 0.1 to 10 keV. We also present the coating technology used for these...... designs and present test results from coatings....

  2. Zr-ZrO sub 2 cermet solar coatings designed by modelling calculations and deposited by dc magnetron sputtering

    CERN Document Server

    Zhang Qi Chu; Lee, K D; Shen, Y G

    2003-01-01

    High solar performance Zr-ZrO sub 2 cermet solar coatings were designed using a numerical computer model and deposited experimentally. The layer thickness and Zr metal volume fraction for the Zr-ZrO sub 2 cermet solar selective coatings on a Zr or Al reflector with a surface ZrO sub 2 or Al sub 2 O sub 3 anti-reflection layer were optimized to achieve maximum photo-thermal conversion efficiency at 80 deg. C under concentration factors of 1-20 using the downhill simplex method in multi-dimensions in the numerical calculation. The dielectric function and the complex refractive index of Zr-ZrO sub 2 cermet materials were calculated using Sheng's approximation. Optimization calculations show that Al sub 2 O sub 3 /Zr-ZrO sub 2 /Al solar coatings with two cermet layers and three cermet layers have nearly identical solar absorptance, emittance and photo-thermal conversion efficiency that are much better than those for films with one cermet layer. The optimized Al sub 2 O sub 3 /Zr-ZrO sub 2 /Al solar coating film w...

  3. Characterization of Cr-O cermet solar selective coatings deposited by using direct-current magnetron sputtering technology

    International Nuclear Information System (INIS)

    Cr-O (Cr-CrO) cermet solar selective coatings with a double cermet layer film structure were prepared by using a special direct-current (dc) magnetron sputtering technology. The typical film structure from the surface to the bottom substrate was an Al2O3 anti-reflection layer on a double Cr-O cermet layer on an Al metal infrared reflection layer. The deposited Cr-O cermet solar selective coating had an absorptance of α = 0.93 - 0.95 and an emittance of ε = 0.09 - 0.10(100 .deg. C). The absorption layers of the Cr-O cermet coatings deposited on glass and silicon substrates were identified as being amorphous by using X-ray diffraction (XRD). Atomic force microscopy (AFM) showed that Cr-O cermet layers were very smooth and that their grain sizes were very small. The result of thermal stability test showed that the Cr-O cermet solar selective coating was stable for use at temperatures of under 400 .deg. C.

  4. Biocompatibility of Niobium Coatings

    OpenAIRE

    René Olivares-Navarrete; Jhon Jairo Olaya; Claudia Ramírez; Sandra Elizabeth Rodil

    2011-01-01

    Niobium coatings deposited by magnetron sputtering were evaluated as a possible surface modification for stainless steel (SS) substrates in biomedical implants. The Nb coatings were deposited on 15 mm diameter stainless steel substrates having an average surface roughness of 2 mm. To evaluate the biocompatibility of the coatings three different in vitro tests, using human alveolar bone derived cells, were performed: cellular adhesion, proliferation and viability. Stainles...

  5. Oxide coating development

    Energy Technology Data Exchange (ETDEWEB)

    Stinton, D.P.

    1995-06-01

    Monolithic SiC heat exchangers and fiber-reinforced SiC-matrix composite heat exchangers and filters are susceptible to corrosion by alkali metals at elevated temperatures. Protective coatings are currently being developed to isolate the SiC materials from the corrodants. Unfortunately, these coatings typically crack and spall when applied to SiC substrates. The purpose of this task is to determine the feasibility of using a compliant material between the protective coating and the substrate. The low-modulus compliant layer could absorb stresses and eliminate cracking and spalling of the protective coatings.

  6. Superhard Nanocomposite Coatings

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The recent development in the field of nanocomposite coatings with good mechanical properties is critically reviewed in this paper. The design principle and materials selection for the nanocomposite coatings are introduced. Different methods for the preparation of superhard nanocomposite coatings are described with emphasis on the magnetron sputtering. Based on recent theoretical and experimental results regarding the appearance of superhardness in nanocomposite coating, lattice parameter changes, crystallite size, microstructure and morphology are reviewed in detail. Also emphasized are the mechanical properties (especially on hardness) and the ways by which the properties are derived.

  7. Development of technique for AR coating and nickel and copper metallization of solar cells. FPS Project: Product development

    Science.gov (United States)

    Taylor, W.

    1982-01-01

    Printed nickel overplated with copper and applied on top of a predeposited silicon nitride antireflective coating system for metallizing solar cells was analyzed. The ESL D and E paste formulations, and the new formulations F, G, H, and D-1 were evaluated. The nickel thick films were tested after firing for stability in the cleaning and plating solutions used in the Vanguard-Pacific brush plating process. It was found that the films are very sensitive to the leaning and alkaline copper solutions. Less sensitivity was displayed to the neutral copper solution. Microscopic and SEM observations show segregation of frit at the silicon nitride thick film interface with loose frit residues after lifting off plated grid lines.

  8. Hydrothermal Synthesis Au-Bi2Te3 Nanocomposite Thermoelectric Film with a Hierarchical Sub-Micron Antireflection Quasi-Periodic Structure

    Directory of Open Access Journals (Sweden)

    Junlong Tian

    2015-06-01

    Full Text Available In this work, Au-Bi2Te3 nanocomposite thermoelectric film with a hierarchical sub-micron antireflection quasi-periodic structure was synthesized via a low-temperature chemical route using Troides helena (Linnaeus forewing (T_FW as the biomimetic template. This method combines chemosynthesis with biomimetic techniques, without the requirement of expensive equipment and energy intensive processes. The microstructure and the morphology of the Au-Bi2Te3 nanocomposite thermoelectric film was analyzed by X-ray diffraction (XRD, field-emission scanning-electron microscopy (FESEM, and transmission electron microscopy (TEM. Coupled the plasmon resonances of the Au nanoparticles with the hierarchical sub-micron antireflection quasi-periodic structure, the Au-Bi2Te3 nanocomposite thermoelectric film possesses an effective infrared absorption and infrared photothermal conversion performance. Based on the finite difference time domain method and the Joule effect, the heat generation and the heat source density distribution of the Au-Bi2Te3 nanocomposite thermoelectric film were studied. The heterogeneity of heat source density distribution of the Au-Bi2Te3 nanocomposite thermoelectric film opens up a novel promising technique for generating thermoelectric power under illumination.

  9. Six-fold hexagonal symmetric nanostructures with various periodic shapes on GaAs substrates for efficient antireflection and hydrophobic properties

    International Nuclear Information System (INIS)

    We fabricated various periodic nanostructures with a six-fold hexagonal symmetry on gallium arsenide (GaAs) substrates using simple process steps, together with a theoretical analysis of their antireflective properties. Elliptical photoresist (PR) nanopillars, which are inevitably generated by the asymmetric intensity distribution of the laser interference, were converted to rounded lens-like patterns by a thermal reflow process without any additional complex optic systems, thus leading to an exact six-fold hexagonal symmetry. Various shaped periodic nanostructures including nanorods, cones, truncated cones, and even parabolic patterns were obtained under different etching conditions using the rounded lens-like PR patterns formed by the reflow process. For the parabolic structure, the calculated lowest average reflectance of ∼ 2.3% was obtained. To achieve better antireflection characteristics, an aluminum-doped zinc oxide (AZO) film was deposited on the GaAs parabolas, which forms an AZO/GaAs parabolic nanostructure. The structure exhibited a low average reflectance of ∼ 1.2% over a wide wavelength region of 350–1800 nm and a hydrophobic surface with a water contact angle of θc ∼ 115°. The calculated reflectances were reasonably consistent with the measured results.

  10. Hydrothermal Synthesis Au-Bi2Te3 Nanocomposite Thermoelectric Film with a Hierarchical Sub-Micron Antireflection Quasi-Periodic Structure.

    Science.gov (United States)

    Tian, Junlong; Zhang, Wang; Zhang, Yuan; Xue, Ruiyang; Wang, Yuhua; Zhang, Zhijian; Zhang, Di

    2015-01-01

    In this work, Au-Bi(2)Te(3) nanocomposite thermoelectric film with a hierarchical sub-micron antireflection quasi-periodic structure was synthesized via a low-temperature chemical route using Troides helena (Linnaeus) forewing (T_FW) as the biomimetic template. This method combines chemosynthesis with biomimetic techniques, without the requirement of expensive equipment and energy intensive processes. The microstructure and the morphology of the Au-Bi(2)Te(3) nanocomposite thermoelectric film was analyzed by X-ray diffraction (XRD), field-emission scanning-electron microscopy (FESEM), and transmission electron microscopy (TEM). Coupled the plasmon resonances of the Au nanoparticles with the hierarchical sub-micron antireflection quasi-periodic structure, the Au-Bi(2)Te(3) nanocomposite thermoelectric film possesses an effective infrared absorption and infrared photothermal conversion performance. Based on the finite difference time domain method and the Joule effect, the heat generation and the heat source density distribution of the Au-Bi(2)Te(3) nanocomposite thermoelectric film were studied. The heterogeneity of heat source density distribution of the Au-Bi(2)Te(3) nanocomposite thermoelectric film opens up a novel promising technique for generating thermoelectric power under illumination. PMID:26047340

  11. Innovations in coating technology.

    Science.gov (United States)

    Behzadi, Sharareh S; Toegel, Stefan; Viernstein, Helmut

    2008-01-01

    Despite representing one of the oldest pharmaceutical techniques, coating of dosage forms is still frequently used in pharmaceutical manufacturing. The aims of coating range from simply masking the taste or odour of drugs to the sophisticated controlling of site and rate of drug release. The high expectations for different coating technologies have required great efforts regarding the development of reproducible and controllable production processes. Basically, improvements in coating methods have focused on particle movement, spraying systems, and air and energy transport. Thereby, homogeneous distribution of coating material and increased drying efficiency should be accomplished in order to achieve high end product quality. Moreover, given the claim of the FDA to design the end product quality already during the manufacturing process (Quality by Design), the development of analytical methods for the analysis, management and control of coating processes has attracted special attention during recent years. The present review focuses on recent patents claiming improvements in pharmaceutical coating technology and intends to first familiarize the reader with the available procedures and to subsequently explain the application of different analytical tools. Aiming to structure this comprehensive field, coating technologies are primarily divided into pan and fluidized bed coating methods. Regarding pan coating procedures, pans rotating around inclined, horizontal and vertical axes are reviewed separately. On the other hand, fluidized bed technologies are subdivided into those involving fluidized and spouted beds. Then, continuous processing techniques and improvements in spraying systems are discussed in dedicated chapters. Finally, currently used analytical methods for the understanding and management of coating processes are reviewed in detail in the last section of the review. PMID:19075909

  12. Superhydrophobic silica coating by dip coating method

    International Nuclear Information System (INIS)

    Herein, we report a simple and low cost method for the fabrication of superhydrophobic coating surface on quartz substrates via sol-gel dip coating method at room temperature. Desired surface chemistry and texture growth for superhydrophobicity developed under double step sol–gel process at room temperature. The resultant superhydrophobic surfaces were characterized by Field-emission scanning electron microscopy (FE-SEM), Atomic force microscopy (AFM), water contact angle (WCA) measurement, differential thermal gravimetric analysis-differential thermal analysis (TGA-DTA) calorimetry and optical spectrometer. Coating shows the ultra high water contact angle about 168 ± 2° and water sliding angle 3 ± 1° and superoleophilic with petroleum oils. This approach allows a simple strategy for the fabrication process of superhydrophilic–superhydrophobic on same surfaces with high thermal stability of superhydrophobicity up to 560 °C. Thus, durability, special wettability and thermal stability of superhydrophobicity expand their application fields.

  13. Plasma assisted chemical vapour deposition for optical coatings

    International Nuclear Information System (INIS)

    Full text: Plasma assisted chemical vapour deposition (PECVD) is commonly used in semiconductor fabrication plants for depositing layers of dielectric materials. Reactive gasses are admitted to a chamber at low pressure and applying an electric field, usually a RF field, generates a plasma. The gasses react to form a solid material on the walls of the chamber and substrates. In this project we are exploring the possibility of applying this method to the growth of multilayer optical thin films. A small prototype system was constructed and optical multi layers of up to 24 layers were deposited over a diameter of 90 mm. The system uses 13.56 MHz RF to generate the plasma in a simple capacitive plate chamber. The gasses used were silane, oxygen and nitrogen. This allows SiO2 (RI 1.45) and Si3N4 (RI 1.93) to be deposited. Multilayer coatings were designed using these materials on TFCalc. The required thickness for the various layers were tabulated and fed into a computer controlling the gas flow during deposition. In this way the structures were deposited semi-automatically. The growing films were monitored using a spectrometer looking at light reflected from the growing film over a range from 400 - 800 nm simultaneously. This data was then used to reconstruct the deposition and analyze deviations from the design. An SEM micrograph of the cross-section of the multilayers was used to obtain relative thicknesses of the individual layers. Other structures deposited include rugate notch filters, coloured filters and broad band anti-reflection layers. Running the prototype has proved the concept and the project has moved to a scale up stage in which a larger version is being constructed at Avtronics Pty Ltd. This aims to coat uniformly over a diameter of 600 mm. Initially, the same materials will be used to produce coatings but fixture work will increase the refractive index range of materials which can be deposited and fully automate the coating process. (authors)

  14. Mechanically Invisible Polymer Coatings

    DEFF Research Database (Denmark)

    2014-01-01

    phase comprises particles, said particles comprising a filler material and an encapsulating coating of a second polymeric material, wherein the backbones of the first and second polymeric materials are the same. The composition may be used in electroactive polymers (EAPs) in order to obtain mechanically...... invisible polymer coatings....

  15. Molecular Adsorber Coating

    Science.gov (United States)

    Straka, Sharon; Peters, Wanda; Hasegawa, Mark; Hedgeland, Randy; Petro, John; Novo-Gradac, Kevin; Wong, Alfred; Triolo, Jack; Miller, Cory

    2011-01-01

    A document discusses a zeolite-based sprayable molecular adsorber coating that has been developed to alleviate the size and weight issues of current ceramic puck-based technology, while providing a configuration that more projects can use to protect against degradation from outgassed materials within a spacecraft, particularly contamination-sensitive instruments. This coating system demonstrates five times the adsorption capacity of previously developed adsorber coating slurries. The molecular adsorber formulation was developed and refined, and a procedure for spray application was developed. Samples were spray-coated and tested for capacity, thermal optical/radiative properties, coating adhesion, and thermal cycling. Work performed during this study indicates that the molecular adsorber formulation can be applied to aluminum, stainless steel, or other metal substrates that can accept silicate-based coatings. The coating can also function as a thermal- control coating. This adsorber will dramatically reduce the mass and volume restrictions, and is less expensive than the currently used molecular adsorber puck design.

  16. HA-Coated Implant

    DEFF Research Database (Denmark)

    Daugaard, Henrik; Søballe, Kjeld; Bechtold, Joan E

    2014-01-01

    The goal of osseointegration of orthopedic and dental implants is the rapid achievement of a mechanically stable and long lasting fixation between living bone and the implant surface. In total joint replacements of cementless designs, coatings of calcium phosphates were introduced as a means of...... evaluating bone-implant fixation with HA coatings....

  17. Coating of graphene

    NARCIS (Netherlands)

    Schneider, G.F.; Dekker, C.

    2014-01-01

    The present invention is in the field of highly crystalline graphene and coating said graphene with a layer. Said graphene may have further structures, such as nanopores, nanogaps, and nanoribbons. The coated graphene can be used for biomolecular analysis and modification, such as DNA-sequencing, as

  18. RADIATION-CURABLE COATINGS

    Science.gov (United States)

    The report gives results of an evaluation of radiation-curable coatings as a technology for reducing volatile organic compound (VOC) emissions from surface coating operations. urvey of the literature was conducted to assess the state of the technology and emissions from radiation...

  19. Rock-hard coatings

    NARCIS (Netherlands)

    Muller, M.

    2007-01-01

    Aircraft jet engines have to be able to withstand infernal conditions. Extreme heat and bitter cold tax coatings to the limit. Materials expert Dr Ir. Wim Sloof fits atoms together to develop rock-hard coatings. The latest invention in this field is known as ceramic matrix composites. Sloof has sign

  20. Catalytic thermal barrier coatings

    Science.gov (United States)

    Kulkarni, Anand A.; Campbell, Christian X.; Subramanian, Ramesh

    2009-06-02

    A catalyst element (30) for high temperature applications such as a gas turbine engine. The catalyst element includes a metal substrate such as a tube (32) having a layer of ceramic thermal barrier coating material (34) disposed on the substrate for thermally insulating the metal substrate from a high temperature fuel/air mixture. The ceramic thermal barrier coating material is formed of a crystal structure populated with base elements but with selected sites of the crystal structure being populated by substitute ions selected to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a higher rate than would the base compound without the ionic substitutions. Precious metal crystallites may be disposed within the crystal structure to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a lower light-off temperature than would the ceramic thermal barrier coating material without the precious metal crystallites.

  1. Charged-particle coating

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, W.L.; Crane, J.K.; Hendricks, C.D.

    1980-08-29

    Advanced target designs require thicker (approx. 300 ..mu..m) coatings and better surface finishes that can be produced with current coating techniques. An advanced coating technique is proposed to provide maximum control of the coating flux and optimum manipulation of the shell during processing. In this scheme a small beam of ions or particles of known incident energy are collided with a levitated spherical mandrel. Precise control of the incident energy and angle of the deposition flux optimizes the control of the coating morphology while controlled rotation and noncontact support of the shell minimizes the possibility of particulate or damage generated defects. Almost infinite variability of the incident energy and material in this process provides increased flexibility of the target designs which can be physically realized.

  2. Modern coating processes

    International Nuclear Information System (INIS)

    Articles collected in this volume explain both the present state of technique and current developments and problems in the environment of the following coating processes: - Hardfacing welding and soldering; - Thermal spraying; - Thin film technique (CVD, PVD); - Galvanising. Apart from basic representation of the conventional use of the different processes, both the new technological and material developments are to the fore. In this context, the purposeful post-treatment of coatings and the combination of different processes to achieve special coating properties should be mentioned. Examples of this show the hot isostatic pressing or laser melting of sprayed coatings, the simultaneous spraying and shot-blasting and the combination of galvanic and thin film techniques for the manufacture of hybrid systems. A further important group of subjects concerns the testing of various coatings. (orig.)

  3. Radiation curable coating compositions

    International Nuclear Information System (INIS)

    The present invention provides a low-toxicity diluent component for radiation curable coating compositions that contain an acrylyl or methacryly oligomer or resin component such as an acrylyl urethane oligomer. The low-toxicity diluent component of this invention is chosen from the group consisting of tetraethlorthosilicate and tetraethoxyethylorthosilicate. When the diluent component is used as described, benefits in addition to viscosity reduction, may be realized. Application characteristics of the uncured coatings composition, such as flowability, leveling, and smoothness are notably improved. Upon curing by exposure to actinic radiation, the coating composition forms a solid, non-tacky surface free of pits, fissures or other irregularities. While there is no readily apparent reactive mechanism by which the orthosilicate becomes chemically bonded to the cured coating, the presence of silicon in the cured coating has been confirmed by scanning electron microscopy. 12 drawing

  4. Charged-particle coating

    International Nuclear Information System (INIS)

    Advanced target designs require thicker (approx. 300 μm) coatings and better surface finishes that can be produced with current coating techniques. An advanced coating technique is proposed to provide maximum control of the coating flux and optimum manipulation of the shell during processing. In this scheme a small beam of ions or particles of known incident energy are collided with a levitated spherical mandrel. Precise control of the incident energy and angle of the deposition flux optimizes the control of the coating morphology while controlled rotation and noncontact support of the shell minimizes the possibility of particulate or damage generated defects. Almost infinite variability of the incident energy and material in this process provides increased flexibility of the target designs which can be physically realized

  5. Coating Reduces Ice Adhesion

    Science.gov (United States)

    Smith, Trent; Prince, Michael; DwWeese, Charles; Curtis, Leslie

    2008-01-01

    The Shuttle Ice Liberation Coating (SILC) has been developed to reduce the adhesion of ice to surfaces on the space shuttle. SILC, when coated on a surface (foam, metal, epoxy primer, polymer surfaces), will reduce the adhesion of ice by as much as 90 percent as compared to the corresponding uncoated surface. This innovation is a durable coating that can withstand several cycles of ice growth and removal without loss of anti-adhesion properties. SILC is made of a binder composed of varying weight percents of siloxane(s), ethyl alcohol, ethyl sulfate, isopropyl alcohol, and of fine-particle polytetrafluoroethylene (PTFE). The combination of these components produces a coating with significantly improved weathering characteristics over the siloxane system alone. In some cases, the coating will delay ice formation and can reduce the amount of ice formed. SILC is not an ice prevention coating, but the very high water contact angle (greater than 140 ) causes water to readily run off the surface. This coating was designed for use at temperatures near -170 F (-112 C). Ice adhesion tests performed at temperatures from -170 to 20 F (-112 to -7 C) show that SILC is a very effective ice release coating. SILC can be left as applied (opaque) or buffed off until the surface appears clear. Energy dispersive spectroscopy (EDS) and x-ray photoelectron spectroscopy (XPS) data show that the coating is still present after buffing to transparency. This means SILC can be used to prevent ice adhesion even when coating windows or other objects, or items that require transmission of optical light. Car windshields are kept cleaner and SILC effectively mitigates rain and snow under driving conditions.

  6. Fluorine Based Superhydrophobic Coatings

    Directory of Open Access Journals (Sweden)

    Jean-Denis Brassard

    2012-05-01

    Full Text Available Superhydrophobic coatings, inspired by nature, are an emerging technology. These water repellent coatings can be used as solutions for corrosion, biofouling and even water and air drag reduction applications. In this work, synthesis of monodispersive silica nanoparticles of ~120 nm diameter has been realized via Stöber process and further functionalized using fluoroalkylsilane (FAS-17 molecules to incorporate the fluorinated groups with the silica nanoparticles in an ethanolic solution. The synthesized fluorinated silica nanoparticles have been spin coated on flat aluminum alloy, silicon and glass substrates. Functionalization of silica nanoparticles with fluorinated groups has been confirmed by Fourier Transform Infrared spectroscopy (FTIR by showing the presence of C-F and Si-O-Si bonds. The water contact angles and surface roughness increase with the number of spin-coated thin films layers. The critical size of ~119 nm renders aluminum surface superhydrophobic with three layers of coating using as-prepared nanoparticle suspended solution. On the other hand, seven layers are required for a 50 vol.% diluted solution to achieve superhydrophobicity. In both the cases, water contact angles were more than 150°, contact angle hysteresis was less than 2° having a critical roughness value of ~0.700 µm. The fluorinated silica nanoparticle coated surfaces are also transparent and can be used as paint additives to obtain transparent coatings.

  7. Improving material-specific dispense processes for low-defect coatings

    Science.gov (United States)

    Brakensiek, Nick; Braggin, Jennifer; Berron, John; Ramirez, Raul; Anderson, Karl; Smith, Brian

    2011-04-01

    The drive to smaller, less expensive, and faster devices requires radical changes in material development. The increased material requirements drive complex processes that in turn drive equipment requirements. For the photolithography area this demand for improved materials is seen in growing requests for device level-specific tuning of organic bottom antireflective coatings (BARCs) or photoresists for certain imaging requirements, such as numerical aperture, immersion conditions, and optical parameters. To test and utilize the myriad of BARC materials, there is a need to install them on a coater-track quickly and efficiently. Installation typically requires a new filter installation, dispense line cleaning, and usually a minimum of 8-10 L of material to clear out bubbles and other nuisance defects before coating test wafers. As the number of materials increases, the ability to quickly prime a new filter becomes increasingly important. In this study, the Entegris IntelliGen® Mini dispense system was utilized to test various pump priming processes to ultimately minimize the volume purged to reach a defect baseline. In addition, the impacts of the filter media and filter retention on priming efficiency were studied. Results show that priming processes that were not matched to the filter in use could actually cause the defects to increase during the process, thus requiring additional purging to reach baseline, and thereby negating any time or volume savings. Properly programmed priming recipes reduced the purging time and the purging volume by 50-70%.

  8. Anticorrosion diffusion coatings

    International Nuclear Information System (INIS)

    The effect of chemical- and heat treatment on corrosion resistance of steels in aqueous solutions of acids, salts and alkalies has been investigated to find a possibility of replacing stainless steel by carbon or low-alloyed steels with diffusion coatings. Data on corrosion resistance of steels with diffusion coatings such as Cr, Cr-Si, Cr-Ti, Cr-Al, Zr-Al, V-Al are presented. The mechanism of fracture of steels with coatings prepared under optimum conditions is studied

  9. Effect of SiO{sub 2} coating in bolometric Ge light detectors for rare event searches

    Energy Technology Data Exchange (ETDEWEB)

    Beeman, J.W. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Gentils, A. [Centre de Spectrométrie Nuclaire et de Spectrométrie de Masse, CNRS and Université Paris-Sud, F-91405 Orsay (France); Giuliani, A., E-mail: andrea.giuliani@csnsm.in2p3.fr [Centre de Spectrométrie Nuclaire et de Spectrométrie de Masse, CNRS and Université Paris-Sud, F-91405 Orsay (France); Università dell' Insubria, Dipartimento di Scienza e Alta Tecnologia, 22100 Como, Italy, (Italy); INFN, Sezione di Milano Bicocca, 20126 Milano (Italy); Mancuso, M. [Università dell' Insubria, Dipartimento di Scienza e Alta Tecnologia, 22100 Como, Italy, (Italy); INFN, Sezione di Milano Bicocca, 20126 Milano (Italy); Pessina, G. [Università di Milano-Bicocca, Dipartimento di Fisica, and INFN, Sezione di Milano Bicocca, 20126 Milano (Italy); Plantevin, O. [Centre de Spectrométrie Nuclaire et de Spectrométrie de Masse, CNRS and Université Paris-Sud, F-91405 Orsay (France); Rusconi, C. [Università dell' Insubria, Dipartimento di Scienza e Alta Tecnologia, 22100 Como, Italy, (Italy); INFN, Sezione di Milano Bicocca, 20126 Milano (Italy)

    2013-05-01

    In germanium-based light detectors for scintillating bolometers, a SiO{sub 2} anti-reflective coating is often applied on the side of the germanium wafer exposed to light with the aim to improve its light collection efficiency. In this paper, we report about a measurement, performed in the temperature range 25–35 mK, of the light-collection increase obtained thanks to this method, which resulted to be of the order of 20%. The procedure followed has been carefully selected in order to minimize systematic effects. The employed light sources have the same spectral features (peaking at ∼630nm wavelength) that will characterize future neutrinoless double beta decay experiments on the isotope {sup 82}Se and based on ZnSe crystals, such as LUCIFER. The coupling between source and light detector reproduces the configuration used in scintillating bolometers. The present measurement clarifies the role of SiO{sub 2} coating and describes a method and a set-up that can be extended to the study of other types of coatings and luminescent materials.

  10. Properties of Transparent Conductive Film with Acrylic Resin Coating%丙烯酸树脂涂层对透明导电薄膜整体性能的影响

    Institute of Scientific and Technical Information of China (English)

    张官理; 伍建华; 霍钟祺; 张晓锋

    2011-01-01

    在有机玻璃(Polymethyl Methacrylate,PMMA)上磁控溅射透明导电金属薄膜,并引入丙烯酸树脂底涂层和面涂层,以期提高透明导电薄膜的耐环境性能,研究了涂层的引入对透明导电膜整体性能的影响.结果表明:引入丙烯酸树脂涂层后,透明导电薄膜的耐环境性能有了明显提高,且丙烯酸树脂涂层由于具有较低折射率,还可作为光学增透层使用;丙烯酸树脂涂层的引入对成膜质量也有一定的改善.%The acrylic resin coating was used before and after magnetic sputtering of transparent conductive film on the PMMA to improving environmental resistance. The properties of transparent conductive film with acrylic resin coating were inquired. The results showed that the environmental resistance of transparent conductive film was significantly improved after using the acrylic resin coating. The acrylic resin coating could be used as a antireflection layer because of its low refractive index. The quality of film sputtering on the acrylic resin coating was improved as the using of acrylic resin coating.

  11. Multilayer optical dielectric coating

    Science.gov (United States)

    Emmett, John L.

    1990-01-01

    A highly damage resistant, multilayer, optical reflective coating includes alternating layers of doped and undoped dielectric material. The doping levels are low enough that there are no distinct interfaces between the doped and undoped layers so that the coating has properties nearly identical to the undoped material. The coating is fabricated at high temperature with plasma-assisted chemical vapor deposition techniques to eliminate defects, reduce energy-absorption sites, and maintain proper chemical stoichiometry. A number of differently-doped layer pairs, each layer having a thickness equal to one-quarter of a predetermined wavelength in the material are combined to form a narrowband reflective coating for a predetermined wavelength. Broadband reflectors are made by using a number of narrowband reflectors, each covering a portion of the broadband.

  12. Inorganic Coatings Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The inorganic Coatings Lab provides expertise to Navy and Joint Service platforms acquisition IPTs to aid in materials and processing choices which balance up-front...

  13. Nanostructured Superhydrophobic Coatings

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-03-01

    This factsheet describes a research project that deals with the nanostructured superhydrophobic (SH) powders developed at ORNL. This project seeks to (1) improve powder quality; (2) identify binders for plastics, fiberglass, metal (steel being the first priority), wood, and other products such as rubber and shingles; (3) test the coated product for coating quality and durability under operating conditions; and (4) application testing and production of powders in quantity.

  14. Advanced coated particle fuels

    International Nuclear Information System (INIS)

    The coated particle fuel (cpf) has been developed for use in high-temperature gas-cooled reactors, but it may find applications in other types of reactors. In JAERI, besides the development of cpf for High Temperature Engineering Test Reactor, conceptual studies of the cpf applications in actinide burner reactors and space reactors have been made. The conceptual design studies as well as the research and development of advanced coatings, ZrC and TiN, are reviewed. (author)

  15. Hydroxyapatite coatings for biomedical applications

    CERN Document Server

    Zhang, Sam

    2013-01-01

    Hydroxyapatite coatings are of great importance in the biological and biomedical coatings fields, especially in the current era of nanotechnology and bioapplications. With a bonelike structure that promotes osseointegration, hydroxyapatite coating can be applied to otherwise bioinactive implants to make their surface bioactive, thus achieving faster healing and recovery. In addition to applications in orthopedic and dental implants, this coating can also be used in drug delivery. Hydroxyapatite Coatings for Biomedical Applications explores developments in the processing and property characteri

  16. Residual stresses within sprayed coatings

    Institute of Scientific and Technical Information of China (English)

    JIANG Yi; XU Bin-shi; WANG Hai-dou

    2005-01-01

    Some important developments of residual stress researches for coating-based systems were studied. The following topics were included the sources of residual stresses in coatings: error analysis of Stoney's equation in the curvature method used for the measurement of coating residual stress, the modeling of residual stress and some analytical models for predicting the residual stresses in coatings. These topics should provide some important insights for the fail-safe design of the coating-based systems.

  17. Multilayer thermal barrier coating systems

    Science.gov (United States)

    Vance, Steven J.; Goedjen, John G.; Sabol, Stephen M.; Sloan, Kelly M.

    2000-01-01

    The present invention generally describes multilayer thermal barrier coating systems and methods of making the multilayer thermal barrier coating systems. The thermal barrier coating systems comprise a first ceramic layer, a second ceramic layer, a thermally grown oxide layer, a metallic bond coating layer and a substrate. The thermal barrier coating systems have improved high temperature thermal and chemical stability for use in gas turbine applications.

  18. Biocompatibility of Niobium Coatings

    Directory of Open Access Journals (Sweden)

    René Olivares-Navarrete

    2011-09-01

    Full Text Available Niobium coatings deposited by magnetron sputtering were evaluated as a possible surface modification for stainless steel (SS substrates in biomedical implants. The Nb coatings were deposited on 15 mm diameter stainless steel substrates having an average surface roughness of 2 mm. To evaluate the biocompatibility of the coatings three different in vitro tests, using human alveolar bone derived cells, were performed: cellular adhesion, proliferation and viability. Stainless steel substrates and tissue culture plastic were also studied, in order to give comparative information. No toxic response was observed for any of the surfaces, indicating that the Nb coatings act as a biocompatible, bioinert material. Cell morphology was also studied by immune-fluorescence and the results confirmed the healthy state of the cells on the Nb surface. X-ray diffraction analysis of the coating shows that the film is polycrystalline with a body centered cubic structure. The surface composition and corrosion resistance of both the substrate and the Nb coating were also studied by X-ray photoelectron spectroscopy and potentiodynamic tests. Water contact angle measurements showed that the Nb surface is more hydrophobic than the SS substrate.

  19. Antireflective sub-wavelength structures for improvement of the extraction efficiency and color rendering index of monolithic white light-emitting diode.

    Science.gov (United States)

    Ou, Yiyu; Corell, Dennis Dan; Dam-Hansen, Carsten; Petersen, Paul Michael; Ou, Haiyan

    2011-03-14

    We have theoretically investigated the influence of antireflective sub-wavelength structures on a monolithic white light-emitting diode (LED). The simulation is based on the rigorous coupled wave analysis (RCWA) algorithm, and both cylinder and moth-eye structures have been studied in the work. Our simulation results show that a moth-eye structure enhances the light extraction efficiency over the entire visible light range with an extraction efficiency enhancement of up to 26 %. Also for the first time to our best knowledge, the influence of sub-wavelength structures on both the color rendering index (CRI) and the correlated color temperature (CCT) of the monolithic white LED have been demonstrated. The CRI of the monolithic white LED could be improved from 92.68 to around 94 by applying a cylinder structure, and the CCT could be modified in a very large range with appropriate design of the cylinder structure. PMID:21445218

  20. Improved light extraction efficiency of GaN-based flip-chip light-emitting diodes with an antireflective interface layer

    Science.gov (United States)

    Wu, Dongxue; Ma, Ping; Liu, Boting; Zhang, Shuo; Wang, Junxi; Li, Jinmin

    2016-05-01

    GaN-based flip-chip light-emitting diodes (FC-LEDs) grown on nanopatterned sapphire substrates (NPSS) are fabricated using self-assembled SiO2 nanospheres as masks during inductively coupled plasma etching. By controlling the pattern spacing, epitaxial GaN can be grown from the top or bottom of patterns to obtain two different GaN/substrate interfaces. The optoelectronic characteristics of FC-LED chips with different GaN/sapphire interfaces are studied. The FC-LED with an antireflective interface layer consisting of a NPSS with GaN in the pattern spacings demonstrates better optical properties than the FC-LED with an interface embedded with air voids. Our study indicates that the two types of FC-LEDs grown on NPSS show higher crystal quality and improved electrical and optical characteristics compared with those of FC-LEDs grown on conventional planar sapphire substrates.

  1. Integrating anti-reflection and superhydrophobicity of moth-eye-like surface morphology on a large-area flexible substrate

    International Nuclear Information System (INIS)

    This paper proposes an ultraviolet nanoimprint lithography (UV-NIL) roll-to-roll (R2R) process with argon and oxygen (Ar–O2) plasma ashing and coating of a dilute perfluorodecyltrichlorosilane (FDTS) layer to fabricate the large-area moth-eye-like surface morphology on a polyethylene terephthalate substrate. By using Maxwell-Garnett's effective medium theory, the optimal dimensions of the moth-eye-like surface morphology was designed and fabricated with UV-NIL R2R process to obtain maximum transmittance ratio. In addition, the base angle (θ = 30.1°) of the moth-eye-like surface morphology was modified with Ar–O2 plasma ashing and coated with a dilute FDTS layer to possess both superhydrophobic and air-retention properties. This increases both the transmittance ratio of 4% and contact angle to 153°. (paper)

  2. Coated particle waste form development

    International Nuclear Information System (INIS)

    Coated particle waste forms have been developed as part of the multibarrier concept at Pacific Northwest Laboratory under the Alternative Waste Forms Program for the Department of Energy. Primary efforts were to coat simulated nuclear waste glass marbles and ceramic pellets with low-temperature pyrolytic carbon (LT-PyC) coatings via the process of chemical vapor deposition (CVD). Fluidized bed (FB) coaters, screw agitated coaters (SAC), and rotating tube coaters were used. Coating temperatures were reduced by using catalysts and plasma activation. In general, the LT-PyC coatings did not provide the expected high leach resistance as previously measured for carbon alone. The coatings were friable and often spalled off the substrate. A totally different concept, thermal spray coating, was investigated at PNL as an alternative to CVD coating. Flame spray, wire gun, and plasma gun systems were evaluated using glass, ceramic, and metallic coating materials. Metal plasma spray coatings (Al, Sn, Zn, Pb) provided a two to three orders-of-magnitude increase in chemical durability. Because the aluminum coatings were porous, the superior leach resistance must be due to either a chemical interaction or to a pH buffer effect. Because they are complex, coated waste form processes rank low in process feasibility. Of all the possible coated particle processes, plasma sprayed marbles have the best rating. Carbon coating of pellets by CVD ranked ninth when compared with ten other processes. The plasma-spray-coated marble process ranked sixth out of eleven processes

  3. Coated particle waste form development

    Energy Technology Data Exchange (ETDEWEB)

    Oma, K.H.; Buckwalter, C.Q.; Chick, L.A.

    1981-12-01

    Coated particle waste forms have been developed as part of the multibarrier concept at Pacific Northwest Laboratory under the Alternative Waste Forms Program for the Department of Energy. Primary efforts were to coat simulated nuclear waste glass marbles and ceramic pellets with low-temperature pyrolytic carbon (LT-PyC) coatings via the process of chemical vapor deposition (CVD). Fluidized bed (FB) coaters, screw agitated coaters (SAC), and rotating tube coaters were used. Coating temperatures were reduced by using catalysts and plasma activation. In general, the LT-PyC coatings did not provide the expected high leach resistance as previously measured for carbon alone. The coatings were friable and often spalled off the substrate. A totally different concept, thermal spray coating, was investigated at PNL as an alternative to CVD coating. Flame spray, wire gun, and plasma gun systems were evaluated using glass, ceramic, and metallic coating materials. Metal plasma spray coatings (Al, Sn, Zn, Pb) provided a two to three orders-of-magnitude increase in chemical durability. Because the aluminum coatings were porous, the superior leach resistance must be due to either a chemical interaction or to a pH buffer effect. Because they are complex, coated waste form processes rank low in process feasibility. Of all the possible coated particle processes, plasma sprayed marbles have the best rating. Carbon coating of pellets by CVD ranked ninth when compared with ten other processes. The plasma-spray-coated marble process ranked sixth out of eleven processes.

  4. POSS(Registered TradeMark) Coatings for Solar Cells: An Update

    Science.gov (United States)

    Brandhorst, Henry; Isaacs-Smith, Tamara; Wells, Brian; Lichtenhan, Joseph D.; Fu, Bruce X.

    2007-01-01

    Presently, solar cells are covered with Ce-doped microsheet cover glasses that are attached with Dow Corning DC 93-500 silicone adhesive. Various antireflection coatings are often applied to the cover glass to increase cell performance. This general approach has been used from the beginning of space exploration. However, it is expensive and time consuming. Furthermore, as the voltage of solar arrays increases, significant arcing has occurred in solar arrays, leading to loss of satellite power. The cause has been traced to differential voltages between strings and the close spacing between them with no insulation covering the edges of the solar cells. In addition, this problem could be ameliorated if the cover glass extended over the edges of the cell, but this would impact packing density. An alternative idea that might solve all these issues and be less expensive and more protective is to develop a coating that could be applied over the entire array. Such a coating must be resistant to atomic oxygen for low earth orbits below about 700 km, it must be resistant to ultraviolet radiation for all earth and near-sun orbits and, of course, it must withstand the damaging effects of space radiation. Coating flexibility would be an additional advantage. Based on past experience, one material that has many of the desired attributes of a universal protective coating is the Dow Corning DC 93-500. Of all the potential optical plastics, it appears to be the most suitable for use in space. As noted above, DC 93-500 has been extensively used to attach cover glasses to crystalline solar cells and has worked exceptionally well over the years. It is flexible and generally resistant to electrons, protons and ultraviolet (UV and VUV) radiation; although a VUV-rejection coating or VUV-absorbing ceria-doped cover glass may be required for long mission durations. It can also be applied in a thin coating (cells and destroy the essential clarity needed for a concentrator lens.

  5. Zr-ZrO2 cermet solar coatings designed by modelling calculations and deposited by dc magnetron sputtering

    Science.gov (United States)

    Zhang, Qi-Chu; Hadavi, M. S.; Lee, K.-D.; Shen, Y. G.

    2003-03-01

    High solar performance Zr-ZrO2 cermet solar coatings were designed using a numerical computer model and deposited experimentally. The layer thickness and Zr metal volume fraction for the Zr-ZrO2 cermet solar selective coatings on a Zr or Al reflector with a surface ZrO2 or Al2O3 anti-reflection layer were optimized to achieve maximum photo-thermal conversion efficiency at 80°C under concentration factors of 1-20 using the downhill simplex method in multi-dimensions in the numerical calculation. The dielectric function and the complex refractive index of Zr-ZrO2 cermet materials were calculated using Sheng's approximation. Optimization calculations show that Al2O3/Zr-ZrO2/Al solar coatings with two cermet layers and three cermet layers have nearly identical solar absorptance, emittance and photo-thermal conversion efficiency that are much better than those for films with one cermet layer. The optimized Al2O3/Zr-ZrO2/Al solar coating film with two cermet layers has a high solar absorptance value of 0.97 and low hemispherical emittance value of 0.05 at 80°C for a concentration factor of 2. The Al2O3/Zr-ZrO2/Al solar selective coatings with two cermet layers were deposited using dc magnetron sputtering technology. During the deposition of Zr-ZrO2 cermet layer, a Zr metallic target was run in a gas mixture of argon and oxygen. By control of oxygen flow rate the different metal volume fractions in the cermet layers were achieved using dc reactive sputtering. A solar absorptance of 0.96 and normal emittance of 0.05 at 80°C were achieved.

  6. Zr-ZrO{sub 2} cermet solar coatings designed by modelling calculations and deposited by dc magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Qichu [School of Physics, University of Sydney, NSW 2006 (Australia); Hadavi, M S [School of Physics, University of Sydney, NSW 2006 (Australia); Lee, K-D [School of Physics, University of Sydney, NSW 2006 (Australia); Shen, Y G [Department of Manufacturing Engineering and Engineering Management, City University of Hong Kong, Hong Kong (China)

    2003-03-21

    High solar performance Zr-ZrO{sub 2} cermet solar coatings were designed using a numerical computer model and deposited experimentally. The layer thickness and Zr metal volume fraction for the Zr-ZrO{sub 2} cermet solar selective coatings on a Zr or Al reflector with a surface ZrO{sub 2} or Al{sub 2}O{sub 3} anti-reflection layer were optimized to achieve maximum photo-thermal conversion efficiency at 80 deg. C under concentration factors of 1-20 using the downhill simplex method in multi-dimensions in the numerical calculation. The dielectric function and the complex refractive index of Zr-ZrO{sub 2} cermet materials were calculated using Sheng's approximation. Optimization calculations show that Al{sub 2}O{sub 3}/Zr-ZrO{sub 2}/Al solar coatings with two cermet layers and three cermet layers have nearly identical solar absorptance, emittance and photo-thermal conversion efficiency that are much better than those for films with one cermet layer. The optimized Al{sub 2}O{sub 3}/Zr-ZrO{sub 2}/Al solar coating film with two cermet layers has a high solar absorptance value of 0.97 and low hemispherical emittance value of 0.05 at 80 deg. C for a concentration factor of 2. The Al{sub 2}O{sub 3}/Zr-ZrO{sub 2}/Al solar selective coatings with two cermet layers were deposited using dc magnetron sputtering technology. During the deposition of Zr-ZrO{sub 2} cermet layer, a Zr metallic target was run in a gas mixture of argon and oxygen. By control of oxygen flow rate the different metal volume fractions in the cermet layers were achieved using dc reactive sputtering. A solar absorptance of 0.96 and normal emittance of 0.05 at 80 deg. C were achieved.

  7. Zr-ZrO2 cermet solar coatings designed by modelling calculations and deposited by dc magnetron sputtering

    International Nuclear Information System (INIS)

    High solar performance Zr-ZrO2 cermet solar coatings were designed using a numerical computer model and deposited experimentally. The layer thickness and Zr metal volume fraction for the Zr-ZrO2 cermet solar selective coatings on a Zr or Al reflector with a surface ZrO2 or Al2O3 anti-reflection layer were optimized to achieve maximum photo-thermal conversion efficiency at 80 deg. C under concentration factors of 1-20 using the downhill simplex method in multi-dimensions in the numerical calculation. The dielectric function and the complex refractive index of Zr-ZrO2 cermet materials were calculated using Sheng's approximation. Optimization calculations show that Al2O3/Zr-ZrO2/Al solar coatings with two cermet layers and three cermet layers have nearly identical solar absorptance, emittance and photo-thermal conversion efficiency that are much better than those for films with one cermet layer. The optimized Al2O3/Zr-ZrO2/Al solar coating film with two cermet layers has a high solar absorptance value of 0.97 and low hemispherical emittance value of 0.05 at 80 deg. C for a concentration factor of 2. The Al2O3/Zr-ZrO2/Al solar selective coatings with two cermet layers were deposited using dc magnetron sputtering technology. During the deposition of Zr-ZrO2 cermet layer, a Zr metallic target was run in a gas mixture of argon and oxygen. By control of oxygen flow rate the different metal volume fractions in the cermet layers were achieved using dc reactive sputtering. A solar absorptance of 0.96 and normal emittance of 0.05 at 80 deg. C were achieved

  8. Optimizing analysis of W-AlN cermet solar absorbing coatings

    International Nuclear Information System (INIS)

    The layer thickness and tungsten metal volume fraction of W-AlN cermet solar selective absorbing coatings on a W, Cu or Al infrared reflector with a surface aluminium oxynitride (AlON) or Al2O3 ceramic anti-reflector layer were optimized using physical modelling calculations. Due to limited published data for the refractive index of AlN, and likely oxygen contamination during reactive sputtering of AlN ceramic materials, AlON was used as the ceramic component and the published value of its refractive index was employed. The dielectric function and then the complex refractive index of W-AlON cermet materials were calculated using the Ping Sheng approximation. The downhill simplex method in multi-dimensions was used in the numerical calculation to achieve maximum photo-thermal conversion efficiency at 3500C under a concentration factor of 30 for a solar collector tube. Optimization calculation results show that the initial graded (ten-step layers) cermet films all converge to something close to a three-layer film structure, which consists of a low metal volume fraction cermet layer on a high metal volume fraction cermet layer on a metallic infrared reflector with a surface ceramic anti-reflection layer. The optimized three-layer solar coatings have a high solar absorptance of 0.95 for AlON and 0.96 for the Al2O3 anti-reflection layer, and a low hemispherical emittance of 0.073 at 350 deg. C. For the optimized three-layer films the solar radiation is efficiently absorbed internally and by phase interference. Thermal loss is very low for optimized three-layer films due to high reflectance values in the thermal infrared wavelength range and a very sharp edge between low solar reflectance and high thermal infrared reflectance. The high metal volume fraction cermet layer has a metal-like optical behaviour in the thermal infrared wavelength range and makes the largest contribution to the increase of emittance compared with that of the metal infrared reflector. (author)

  9. Performance enhancement of mc-Si solar cells due to synergetic effect of plasma texturization and SiN{sub x}:H AR coating

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, B.; Bhattacharya, S.; Saxena, A.K.; Reddy, S.R.; Bhogra, R.K. [BHEL-ASSCP, C/o BHEL House, Siri Fort, New Delhi 110049 (India)

    2010-08-15

    The present paper discusses the plausible physical processes dominant during plasma texturization of multicrystalline silicon (mc-Si) wafers, deposition of silicon nitride (SiN{sub x}) antireflection (AR) coating and firing of contacts through it. During plasma texturization, it is observed that by using low RF power density and loading wafers on the ground electrode, the texturization process is dominated by chemical etching. The resulting surface of the wafer shows low-reflectivity (<10% in wavelength range 350-800 nm) and low-defect density leading to improved minority carrier lifetime. It is postulated that plasma-etched nanoscale structures accelerate the migration of hydrogen released during firing of contacts. As a result of these physical processes, an improvement up to {proportional_to}2.4% in absolute efficiency of large area ({proportional_to}149 cm{sup 2}) multicrystalline silicon solar cells has been achieved. (author)

  10. White coat, patient gown.

    Science.gov (United States)

    Wellbery, Caroline; Chan, Melissa

    2014-12-01

    Much has been written about the symbolic function of the white coat: its implications of purity, its representation of authority and professionalism, and its role in consolidating a medical hierarchy. By contrast, the medical literature has paid almost no attention to the patient gown. In this article, we argue that in order to understand the full implications of the white coat in the doctor-patient relationship, we must also take into account patients' dress, and even undress. We explore contemporary artistic images of white coat and patient gown in order to reveal the power differential in the doctor-patient relationship. Artistic representations capture some of the cultural ambivalence surrounding the use of the white coat, which confers professional status on its wearer, while undermining his or her personal identity. At the other end of the sartorial spectrum, hospital gowns also strip wearers of their identity, but add to this an experience of vulnerability. Although compelling reasons for continuing to wear the white coat in circumscribed settings persist, physicians should be mindful of its hierarchical implications. Ample room remains for improving patients' privacy and dignity by updating the hospital gown. PMID:24687912

  11. Conductive epoxypolyamide coating composition

    Energy Technology Data Exchange (ETDEWEB)

    Mirabeau, M.N.; Rohrbacher, F.

    1991-10-01

    This patent describes a conductive coating composition comprising a film forming binder and pigment in a pigment to binder weight ratio of about 15:100 to 100:100. It comprises 40-70% by weight of an amine component having at least two reactive amine groups selected from the group consisting of an amine, polyamide, polyamido amine resin or mixtures thereof; and 30-60% by weight of an epoxy resin having at least two epoxy groups per resin molecule; wherein the pigment comprises an electrically conductive pigment that comprises silica selected from the group consisting of amorphous silica, a silica containing material or silica coated pigment, the silica being in association with a two- dimensional network of antimony-containing tin oxide crystallites in which the antimony content ranges from about 1-30% by weight of the tin oxide and the composition forms a coating having a surface conductivity of at least 100 Ransburg units.

  12. Preparation of hydrophobic coatings

    Science.gov (United States)

    Branson, Eric D.; Shah, Pratik B.; Singh, Seema; Brinker, C. Jeffrey

    2009-02-03

    A method for preparing a hydrophobic coating by preparing a precursor sol comprising a metal alkoxide, a solvent, a basic catalyst, a fluoroalkyl compound and water, depositing the precursor sol as a film onto a surface, such as a substrate or a pipe, heating, the film and exposing the film to a hydrophobic silane compound to form a hydrophobic coating with a contact angle greater than approximately 150.degree.. The contact angle of the film can be controlled by exposure to ultraviolet radiation to reduce the contact angle and subsequent exposure to a hydrophobic silane compound to increase the contact angle.

  13. Bioceramics for implant coatings

    Directory of Open Access Journals (Sweden)

    Allison A Campbell

    2003-11-01

    Early research in this field focused on understanding the biomechanical properties of metal implants, but recent work has turned toward improving the biological properties of these devices. This has led to the introduction of calcium phosphate (CaP bioceramics as a bioactive interface between the bulk metal impart and the surrounding tissue. The first CaP coatings were produced via vapor phase processes, but more recently solution-based and biomimetic methods have emerged. While each approach has its own intrinsic materials and biological properties, in general CaP coatings promise to improve implant biocompatibility and ultimately implant longevity.

  14. Methods and means for coating paper by film coating

    NARCIS (Netherlands)

    van der Maarel, Marc; Ter Veer, Arend Berend Cornelis; Vrieling-Smit, Annet; Delnoye, Pierre

    2015-01-01

    This invention relates to the field of paper coating, more in particular to means and methods for providing paper with at least one layer of pigment using film coating to obtain a well printable surface. Provided is a method for preparing coated paper comprising the steps of: a) providing a pigmente

  15. Optical coatings for fiber lasers

    Institute of Scientific and Technical Information of China (English)

    HONG Dong-mei; ZHU Zhen; YUE Wei

    2005-01-01

    Fiber laser is the future development direction for the high energy lasers. This paper describs two kinds of optical coatings for fiber laser, including long and short wave pass filters. The one characteristic of fiber laser coatings lies in that coatings should separate two closely wavelength light including laser pump wavelength (980 nm) and laser irradiation wavelength(1 050~1 100 nm). At the same time, the coatings should have high laser damage threshold.

  16. Carbon coatings for medical implants

    OpenAIRE

    K. Bakowicz-Mitura; P. Couvrat; I. Kotela; P. Louda; D. Batory; J. Grabarczyk

    2007-01-01

    Purpose: In this paper we report in vitro and in vivo results of Nanocrystalline Diamond Coatings whichare used in medicine onto medical implants The very important property of carbon coatings is the protectionliving organism against the metalosis. Different medical implants with complicated shapes are covering byNanocrystalline Diamond Coatings by RF dense plasma CVD.Design/methodology/approach: 1) Material characterizations of deposited coatings have been evaluated by using:Transmission Ele...

  17. Foam coating of filtration media

    OpenAIRE

    Johansson, Mirva

    2015-01-01

    The objective of this thesis was to find out if foam coating could be applied to non-woven filtration media. The goal was to increase collection efficiency without significantly decreasing air permeability. In the theoretical part, foams and their characteristics were the centre of attention. Coating in general and, of course, foam coating were also studied. The empirical part consisted of series of foaming experiments and pilot scale coating experiments. In the foaming experiments differ...

  18. Tribological characterization of selected hard coatings

    OpenAIRE

    Karlsson, Patrik

    2009-01-01

    Hard coatings are often used for protection of tool surfaces due to coating properties like low friction and high wear resistance. Even though many of the hard coatings have been tested for wear, it is important to try new wear test setups to fully understand tribological mechanisms and the potential of hard coatings. Few experiments have been performed with dual-coated systems where the sliding contact surfaces are coated with the same, or different, hard coating. The dual-coated system coul...

  19. TABLET COATING TECHNIQUES: CONCEPTS AND RECENT TRENDS

    Directory of Open Access Journals (Sweden)

    Gupta Ankit

    2012-09-01

    Full Text Available Tablet coating is a common pharmaceutical technique of applying a thin polymer-based film to a tablet or a granule containing active pharmaceutical ingredients (APIs. Solid dosage forms are coated for a number of reasons, the most important of which is controlling the release profiles. The amount of coating on the surface of a tablet is critical to the effectiveness of the oral dosage form. Tablets are usually coated in horizontal rotating pans with the coating solution sprayed onto the free surface of the tablet bed. The advantages of tablet coating are taste masking, odour masking, physical and chemical protection, protects the drug from the gastric environment etc. There are various techniques for tablet coating such as sugar coating, film coating, and enteric coating. Recent trends in pharmaceutical technologies are the development of coating methods which overcomes the various disadvantages associated with solvent based coatings. In these latest technologies coating materials are directly coated onto the surface of solid dosage forms without using any solvent. Various solventless coatings are available such as electrostatic dry coating, magnetically assisted impaction coating, compression coating, hot melt coating, powder coating, and supercritical fluid coating. Supercell Coating Technology is a revolutionary tablet coating that accurately deposits controlled amounts of coating materials on tablets even if they are extremely hygroscopic or friable. Magnetically assisted impaction coating, electrostatic dry coating in solventless coatings, aqueous film coating and Supercell coating technology are also available recent technique of coating. An ideal tablet should be free from any visual defect or functional defect. The advancements and innovations in tablet manufacture have not decreased the problems, often encountered in the production, instead have increased the problems, mainly because of the complexities of tablet presses; and/or the

  20. Niobium coating techniques

    CERN Document Server

    Calatroni, S

    2008-01-01

    We will give a historical overview of the niobium on copper sputtering technology for RF cavities and discuss the main advantages and disadvantages with respect to bulk niobium cavities. Some highlights of the present understanding will be given and some recent developments in the coating technology will be discussed.

  1. Coatings for transport industry

    Directory of Open Access Journals (Sweden)

    Krzysztof LUKASZKOWICZ

    2014-09-01

    Full Text Available The investigations concerned structural analysis, as well as mechanical properties and wear resistant of MeN/DLC double-layer coating deposited by hybrid PVD/PACVD method. In sliding dry friction conditions, after the break-in time, the friction coefficient for the investigated elements is set in the range between 0.03-0.06.

  2. Rheology of Coating Materials and Their Coating Characteristics

    Science.gov (United States)

    Grabsch, C.; Grüner, S.; Otto, F.; Sommer, K.

    2008-07-01

    Lots of particles used in the pharmaceutical and the food industry are coated to protect the core material. But almost no investigations about the coating material behavior do exist. In this study the focus was on the rheological material properties of fat based coating materials. Rotational shear experiments to determine the viscosity of a material were compared to oscillatory shear tests to get information about the vicoelastic behavior of the coating materials. At the liquid state the viscosity and the viscoelastic properties showed a good analogy. The viscoelastic properties of the solid coating materials yielded differences between materials that have the same properties at the liquid state.

  3. Active coatings technologies for tailorable military coating systems

    Science.gov (United States)

    Zunino, J. L., III

    2007-04-01

    The main objective of the U.S. Army's Active Coatings Technologies Program is to develop technologies that can be used in combination to tailor coatings for utilization on Army Materiel. The Active Coatings Technologies Program, ACT, is divided into several thrusts, including the Smart Coatings Materiel Program, Munitions Coatings Technologies, Active Sensor packages, Systems Health Monitoring, Novel Technology Development, as well as other advanced technologies. The goal of the ACT Program is to conduct research leading to the development of multiple coatings systems for use on various military platforms, incorporating unique properties such as self repair, selective removal, corrosion resistance, sensing, ability to modify coatings' physical properties, colorizing, and alerting logistics staff when tanks or weaponry require more extensive repair. A partnership between the U.S. Army Corrosion Office at Picatinny Arsenal, NJ along with researchers at the New Jersey Institute of Technology, NJ, Clemson University, SC, University of New Hampshire, NH, and University of Massachusetts (Lowell), MA, are developing the next generation of Smart Coatings Materiel via novel technologies such as nanotechnology, Micro-electromechanical Systems (MEMS), meta-materials, flexible electronics, electrochromics, electroluminescence, etc. This paper will provide the reader with an overview of the Active Coatings Technologies Program, including an update of the on-going Smart Coatings Materiel Program, its progress thus far, description of the prototype Smart Coatings Systems and research tasks as well as future nanotechnology concepts, and applications for the Department of Defense.

  4. Ceramic coating on ceramic with metallic bond coating

    Science.gov (United States)

    Kishitake, K.; Era, H.; Otsubo, F.; Sonoda, T.

    1997-09-01

    The change in structure and adhesion strength of the interface by heating in air has been investigated for a plasma- sprayed alumina coating on a ceramic substrate with a 50Ni- 50Cr alloy bond coating. A veined structure composed of NiO, NiCr 2O4, and NiAl2O4 oxides grew from the bond coating into cracks or pores in the top coating and the alumina substrate after heating at 1273 K for 20 h in air. The NiAl2O4 spinel may have formed by the oxidization of nickel, which subsequently reacted with the alumina coating or the substrate. The mechanism of the penetration of the spinel oxides into the cracks or pores is not clear. The adhesion strength of the coating is increased to about 15 MPa after heating at 1273 K for 20 h in air, compared to an as- sprayed coating strength of only 1.5 MPa.

  5. Flame-coating method and flame-coating device

    International Nuclear Information System (INIS)

    The method and the device of the present invention improve the quality and operation efficiency of coating applied to corner portions of under water reactor structural components of a nuclear reactor. Namely, powders for the flame-coating are provided with ferromagnetic property in a step of forming coating films to underwater structural members by an underwater flame-coating method in a nuclear reactor. A flow of plasma arc can be bent by applying magnetic fields to the flame-coating plasma arc. Accordingly, coatings can be applied to corner portions particularly to pad-weld portions among welded members. Further, the flame-coating can be applied while being conformed to the shape of the place where a surface layer is formed, by controlling the extension of the plasma arc by making the shape of the plasma arc irradiated on the surface of a work rectangular, elliptic or linear. (I.S.)

  6. The Effect of CeO2 Antireflection Layer on the Optical Properties of Thermochromic VO2 Film for Smart Window System

    Science.gov (United States)

    Koo, Hyun; Shin, Dongmin; Bae, Sung-Hwan; Ko, Kyeong-Eun; Chang, Se-Hong; Park, Chan

    2013-11-01

    CeO2-VO2 bilayer structure was fabricated to investigate the effect of depositing CeO2 film on the optical properties of VO2 film for smart window application. CeO2 was employed as an antireflection (AR) layer material of VO2 film because of its advantages which include high transparency in the visible-near infrared range and high refractive index. All the films were deposited on soda-lime glass substrate by pulsed laser deposition method. Optical calculations were carried out using transfer-matrix method for the purpose of designing CeO2-VO2 bilayer structure with enhanced integrated luminous transmittance (T lum) and switching efficiency (ΔT sol). The optical constants of VO2 and CeO2 films needed for the optical calculation were measured by spectroscopic ellipsometer. The curve of T lum the shape of which depends on the thickness of CeO2 layer, was calculated in each VO2 sample, which showed two maxima. The samples were divided into two groups; one for the highest enhancement of T lum and the other for balanced enhancement between T lum and ΔT sol. The sample with the structure of ~60 nm CeO2 AR layer on 39-nm thick VO2 film showed large increase of T lum (~27%) with ΔT sol of ~5%, which is the largest increase in T lum reported so far. Two samples in the other group showed the balanced enhancement in T lum (~57, ~50%) and ΔT sol (~9, ~10.5%). The effect of CeO2 AR layer on the optical properties of VO2 film was confirmed with the optical calculation and the experimental results. CeO2-VO2 bilayer structure showed notable improvement of optical properties compared to the single VO2 film, indicating that CeO2 layer can be effectively used as the antireflection layer while working as a protective layer that can prevent the oxidation of VO2 layer as well.

  7. Infrared optical coatings in SITP

    Institute of Scientific and Technical Information of China (English)

    LIU Ding-quan; ZHANG Feng-shan

    2005-01-01

    Infrared optical coatings in SITP (Shanghai Institute of Technical Physics) mainly cover the spectrum range from 0.7 μm to 15 μm, and visible and near-UV range are also been included. The coatings are mainly used for metal-reflectance mirrors, Anti-reflection(AR) lens and windows, filters, and dichroic beam splitters. Coatings passed some dependability tests. These optical coated devices usually consist in a remote observing instrument. Most coating materials are commercial products. And one kind of special material PbTe is made by ourselves. Some main results of our research department are reported.

  8. Graphite coating of nuclear fuels

    International Nuclear Information System (INIS)

    This paper gives an account of work conducted on graphite coating of (1) zircaloy fuel tubes for CANDU type power reactors and (2) stainless steel bearing plates for S3F vault structure commissioned at Tarapur for storage of radioactive waste. Graphite has been chosen as a coating material because it is not only an excellent lubricating material but also can withstand severe radiation from nuclear fuel or radioactive waste up to fairly high temperatures. The paper first describes in detail the equipments and experimental procedure standardised to achieve an adherent graphite coating of 5 to 9 μm thickness by using alcohol based suspension of graphite. Graphite coated tubes were evaluated by subjecting it to various destructive and nondestructive testing. Thousands of fuel tubes were coated so far and loaded in RAPP-2 for studying their inpile behaviour. Finally a flowsheet is presented to achieve the graphite coating on fuel tubes as per specifications. The second part of the paper deals with the various techniques examined to obtain the graphite coating on 450 mm square stainless steel plates with alcohol based graphite suspension. An unique spray coating procedure involving both graphite suspension and lacquor was evolved for carrying out the coating operation at site. Co-efficient of friction between graphite coated SS plates was found to be as low as 6.77 per cent. A batch of 280 SS bearing plates were coated with graphite and utilised for commissioning the vault structure at Tarapur. (author). 5 figures

  9. Methods for Coating Particulate Material

    Science.gov (United States)

    Littman, Howard (Inventor); Plawsky, Joel L. (Inventor); Paccione, John D. (Inventor)

    2013-01-01

    Methods and apparatus for coating particulate material are provided. The apparatus includes a vessel having a top and a bottom, a vertically extending conduit having an inlet in the vessel and an outlet outside of the vessel, a first fluid inlet in the bottom of the vessel for introducing a transfer fluid, a second fluid inlet in the bottom of the vessel for introducing a coating fluid, and a fluid outlet from the vessel. The method includes steps of agitating a material, contacting the material with a coating material, and drying the coating material to produce a coated material. The invention may be adapted to coat aerogel beads, among other materials. A coated aerogel bead and an aerogel-based insulation material are also disclosed.

  10. BIODEGRADABLE COATING FROM AGATHIS ALBA

    Directory of Open Access Journals (Sweden)

    NORYAWATI MULYONO

    2012-11-01

    Full Text Available The adhesive property of copal makes it as a potential coating onto aluminum foil to replace polyethylene. This research aimed to develop copal-based coating. The coating was prepared by extracting the copal in ethyl acetate and dipping the aluminium foil in ethyl acetate soluble extract of copal. The characterization of coating included its thickness, weight, thermal and chemical resistance, and biodegradation. The results showed that the coating thickness and weight increased as the copal concentration and dipping frequency increased. Thermal resistance test showed that the coating melted after being heated at 110°C for 30 min. Copal-based coating wasresistant to acidic solution (pH 4.0, water, and coconut oil, but was deteriorated in detergent 1% (w/v and basic solution (pH 10.0. Biodegradability test using Pseudomonas aeruginosa showed weight reduction of 76.82% in 30 days.

  11. Diamond-Like Carbon Coatings as Encapsulants for Photovoltaic Solar Cells

    International Nuclear Information System (INIS)

    High-quality single-layer and bilayer diamond-like carbon (DLC) thin films are fabricated by two technologies, namely, ion-assisted plasma-enhanced deposition (IAPED) and electron cyclotron resonance (ECR) deposition. Deposition on various substrates, such as sapphires and solar cells, has been performed at low substrate temperatures (50 ∼ 80 C). The two deposition technologies allow good control over the growth conditions to produce DLC films with desired optical properties, thickness, and energy bandgap. The bilayer-structured DLC can be fabricated by using IAPED for the bottom layer followed by ECR for the top layer, or just by IAPED for both layers with different compositions. The DLC films have shown good spatial uniformity, density, microhardness, and adhesion strength. They exhibit excellent stability against attack by strong acids, prolonged damp-heat exposure at 85 C and 85% relative humidity, mechanical scratch, ultrasonication, and irradiation by ultraviolet (UV), protons, and electrons. When deposited on crystalline Si and GaAs solar cells in single-layer and/or bilayer structure, the DLC films not only serve as antireflection coating and protective encapsulant, but also improve the cell efficiencies

  12. QUALITY IN METALLIZED COATING APPLICATIONS

    Directory of Open Access Journals (Sweden)

    Bülent Eker

    2010-12-01

    Full Text Available Metalized coating is attained by atomizing the coating metal by melting with proper gas (propane, acetylene or others and oxygen compound and then spraying it with compressed air all over the surface to be coated. Metallization in the application is the process of vaporization of the needed metal with tungsten in vacuumed media. This system among the PVD Coating groups is known as Evaporation Coating all through the world. Although the very fine metal layer that condenses over the product to be coated varies from sector to sector; it is generally used with aesthetic and decorative aims. The surface of the part to be coated is cleaned off the effects such as dirt, dust and oils etc. this cleaning method varies according to the size, shape and material of the piece to be coated. Surface cleaning before coating is very important in the sense of coating life, quality and strength. Otherwise, expected yield cannot be attained from the metalized and corrosion start can be observed shortly due to remnants on the places which are not thoroughly cleaned. Since metallization is a vaporization method; it is ionized by melting on all places which are in high-vacuumed. But there occurs an adsorption problem on some plastic types, therefore a smooth coating is attained applying an adherence through interlayer on these products before coating or with corona application. In food packaging sector metalized coated products are used because of their barrier feature towards light, water vapor, oxygen and other gases. This method of packaging is widely used in such kinds of sectors due to being most economical in packaging sector. For example; food packaging sector which holds a great place in flexible packaging group uses metalized coating system due to their barrier feature of metalized film with the aim of preventing oxidation of food products, decreasing the need of protective addition agent and extending the shell-life. Moreover cosmetic packaging group and

  13. Coat proteins isolated from clathrin coated vesicles can assemble into coated pits

    OpenAIRE

    1989-01-01

    Isolated human fibroblast plasma membranes that were attached by their extracellular surface to a solid substratum contained numerous clathrin coated pits that could be removed with a high pH buffer (Moore, M.S., D.T. Mahaffey, F.M. Brodsky, and R.G.W. Anderson. 1987. Science [Wash. DC]. 236:558-563). When these membranes were incubated with coat proteins extracted from purified bovine coated vesicles, new coated pits formed that were indistinguishable from native coated pits. Assembly was de...

  14. Superelastic Orthopedic Implant Coatings

    Science.gov (United States)

    Fournier, Eric; Devaney, Robert; Palmer, Matthew; Kramer, Joshua; El Khaja, Ragheb; Fonte, Matthew

    2014-07-01

    The demand for hip and knee replacement surgery is substantial and growing. Unfortunately, most joint replacement surgeries will fail within 10-25 years, thereby requiring an arduous, painful, and expensive revision surgery. To address this issue, a novel orthopedic implant coating material ("eXalt") has been developed. eXalt is comprised of super elastic nitinol wire that is knit into a three-dimensional spacer fabric structure. eXalt expands in vivo to conform to the implantation site and is porous to allow for bone ingrowth. The safety and efficacy of eXalt were evaluated through structural analysis, mechanical testing, and a rabbit implantation model. The results demonstrate that eXalt meets or exceeds the performance of current coating technologies with reduced micromotion, improved osseointegration, and stronger implant fixation in vivo.

  15. Acrylic purification and coatings

    CERN Document Server

    ,

    2012-01-01

    Radon (Rn) and its decay daughters are a well-known source of background in direct WIMP detection experiments, as either a Rn decay daughter or an alpha particle emitted from a thin inner surface layer of a detector could produce a WIMP-like signal. Different surface treatment and cleaning techniques have been employed in the past to remove this type of contamination. A new method of dealing with the problem has been proposed and used for a prototype acrylic DEAP-1 detector. Inner surfaces of the detector were coated with a layer of ultra pure acrylic, meant to shield the active volume from alphas and recoiling nuclei. An acrylic purification technique and two coating techniques are described: a solvent-borne (tested on DEAP-1) and solvent-less (being developed for the full scale DEAP-3600 detector).

  16. Thermal barrier coating materials

    OpenAIRE

    Clarke, David R.; Simon R. Phillpot

    2005-01-01

    Improved thermal barrier coatings (TBCs) will enable future gas turbines to operate at higher gas temperatures. Considerable effort is being invested, therefore, in identifying new materials with even better performance than the current industry standard, yttria-stabilized zirconia (YSZ). We review recent progress and suggest that an integrated strategy of experiment, intuitive arguments based on crystallography, and simulation may lead most rapidly to the development of new TBC materials.

  17. New casting coatings

    International Nuclear Information System (INIS)

    In this project the results of the researches about the influence of the four types of ceramic coatings of the evaporating patterns (on the basis of talc, mullite, zircon and cordierite) on the talc of the Lost Foam process and the castings quality are presented. For the valid evaluation of the results, some parallel examinations of the quality of castings obtained by casting in sand were carried out. (Original)

  18. Environmentally regulated aerospace coatings

    Science.gov (United States)

    Morris, Virginia L.

    1995-01-01

    Aerospace coatings represent a complex technology which must meet stringent performance requirements in the protection of aerospace vehicles. Topcoats and primers are used, primarily, to protect the structural elements of the air vehicle from exposure to and subsequent degradation by environmental elements. There are also many coatings which perform special functions, i.e., chafing resistance, rain erosion resistance, radiation and electric effects, fuel tank coatings, maskants, wire and fastener coatings. The scheduled promulgation of federal environmental regulations for aerospace manufacture and rework materials and processes will regulate the emissions of photochemically reactive precursors to smog and air toxics. Aerospace organizations will be required to identify, qualify and implement less polluting materials. The elimination of ozone depleting chemicals (ODC's) and implementation of pollution prevention requirements are added constraints which must be addressed concurrently. The broad categories of operations affected are the manufacture, operation, maintenance, and repair of military, commercial, general aviation, and space vehicles. The federal aerospace regulations were developed around the precept that technology had to be available to support the reduction of organic and air toxic emissions, i.e., the regulations cannot be technology forcing. In many cases, the regulations which are currently in effect in the South Coast Air Quality Management District (SCAQMD), located in Southern California, were used as the baseline for the federal regulations. This paper addresses strategies used by Southern California aerospace organizations to cope with these regulatory impacts on aerospace productions programs. All of these regulatory changes are scheduled for implementation in 1993 and 1994, with varying compliance dates established.

  19. Biomimetic implant coatings.

    Science.gov (United States)

    Eisenbarth, E; Velten, D; Breme, J

    2007-02-01

    Biomaterials and tissue engineering technologies are becoming increasingly important in biomedical practice, particularly as the population ages. Cellular responses depend on topographical properties of the biomaterial at the nanometer scale. Structures on biomaterial surfaces are used as powerful tools to influence or even control interactions between implants and the biological system [; ]. The influence of nanometer sized surface structures on osteoblastlike cell interactions was tested with niobium oxide coatings on polished titanium slices (cp-Ti grade 2). The aim of the study was to investigate the influence of nanoscopic surface structures on osteoblast interactions in order to support collagen I production and cell adhesion. The coatings were done by means of the sol-gel process. The surface structure was adjusted by annealing of the metaloxide ceramic coatings due to temperature depended crystal growth. The applied annealing temperatures were 450, 550 and 700 degrees C for 1 h, corresponding to Ra-numbers of 7, 15 and 40 nm. The surfaces were characterized by means of AFM, DTA/TG, diffractometry and white light interferometry. The cell reactions were investigated concerning adhesion kinetics, migration, spreading, cell adhesion, and collagen I synthesis. The smooth surface (Ra=7 nm) resulted in the fastest cell anchorage and cell migration. The closest cell adhesion was reached with the surface structure of Ra=15 nm. The roughest surface (Ra=40 nm) impedes the cell migration as well as a proper spreading of the cells. The best results concerning cell adhesion and spreading was reached with an intermediate surface roughness of Ra=15 nm of the niobium oxide coating on cp-titanium slices. PMID:16828342

  20. Anti-Corrosion Coating

    Science.gov (United States)

    1986-01-01

    SuperSpan RM 8000 is an anti-corrosion coating which effectively counteracts acid degradation, abrasive wear, and cracking in power industry facilities. It was developed by RM Industrial Products Company, Inc. with NERAC assistance. It had previously been necessary to shut down plants to repair or replace corroded duct-work in coal burning utilities. NASA-developed technology was especially useful in areas relating to thermoconductivity of carbon steel and the bonding characteristics of polymers. The product has sold well.

  1. Simulation and Experimental Study on Anti-reflection Characteristics of Nano-patterned Si Structures for Si Quantum Dot-Based Light-Emitting Devices.

    Science.gov (United States)

    Shao, Wenyi; Lu, Peng; Li, Wei; Xu, Jun; Xu, Ling; Chen, Kunji

    2016-12-01

    Surface-textured structure is currently an interesting topic since it can efficiently reduce the optical losses in advanced optoelectronic devices via light management. In this work, we built a model in finite-difference time-domain (FDTD) solutions by setting the simulation parameters based on the morphology of the Si nanostructures and compared with the experimental results in order to study the anti-reflection behaviors of the present nano-patterned structures. It is found that the reflectance is gradually reduced by increasing the depth of Si nanostructures which is in well agreement with the experimental observations. The reflectance can be lower than 10 % in the light range from 400 to 850 nm for Si nano-patterned structures with a depth of 150 nm despite the quite low aspect ratio, which can be understood as the formation of gradually changed index layer and the scattering effect of Si nano-patterned structures. By depositing the Si quantum dots/SiO2 multilayers on nano-patterned Si substrate, the reflectance can be further suppressed and the luminescence intensity centered at 820 nm from Si quantum dots is enhanced by 6.6-fold compared with that of flat one, which can be attributed to the improved light extraction efficiency. However, the further etch time causes the reduction of luminescence intensity from Si quantum dots which may ascribe to the serious surface recombination of carriers. PMID:27356564

  2. Large-area one-step assembly of three-dimensional porous metal micro/nanocages by ethanol-assisted femtosecond laser irradiation for enhanced antireflection and hydrophobicity.

    Science.gov (United States)

    Li, Guoqiang; Li, Jiawen; Zhang, Chenchu; Hu, Yanlei; Li, Xiaohong; Chu, Jiaru; Huang, Wenhao; Wu, Dong

    2015-01-14

    The capability to realize 2D-3D controllable metallic micro/nanostructures is of key importance for various fields such as plasmonics, electronics, bioscience, and chemistry due to unique properties such as electromagnetic field enhancement, catalysis, photoemission, and conductivity. However, most of the present techniques are limited to low-dimension (1D-2D), small area, or single function. Here we report the assembly of self-organized three-dimensional (3D) porous metal micro/nanocages arrays on nickel surface by ethanol-assisted femtosecond laser irradiation. The underlying formation mechanism was investigated by a series of femtosecond laser irradiation under exposure time from 5 to 30 ms. We also demonstrate the ability to control the size of micro/nanocage arrays from 0.8 to 2 μm by different laser pulse energy. This method features rapidness (∼10 min), simplicity (one-step process), and ease of large-area (4 cm(2) or more) fabrication. The 3D cagelike micro/nanostructures exhibit not only improved antireflection from 80% to 7% but also enhanced hydrophobicity from 98.5° to 142° without surface modification. This simple technique for 3D large-area controllable metal microstructures will find great potential applications in optoelectronics, physics, and chemistry. PMID:25473879

  3. The Study of Femtosecond Laser Irradiation on GaAs Solar Cells With TiO2/SiO2 Anti-Reflection Films

    Science.gov (United States)

    Hua, Yinqun; Shi, Zhiguo; Wu, Wenhui; Chen, Ruifang; Rong, Zhen; Ye, Yunxia; Liu, Haixia

    Femtosecond laser ablation on GaAs solar cells for space power has been investigated. In particular, we studied the effects of laser energy and laser number on the ablation of solar cells. Furthermore, the morphologies and microstructure of ablation were characterized by the non-contact optical profilometer and scanning electron microscope (SEM). The photovoltaic properties were tested by the volt ampere characteristic test system. The abaltion threshold of the TiO2/SiO2 anti-reflection film of GaAs solar cells was obtained from the linear fit of the dependence of the square diameter of the ablated area with the natural logarithm of the femtosecond laser pulse energy, the resulting threshold of the laser fluence is about 0.31J/cm2, and the corresponding energy is 5.4uJ. The ablation depth showed nonlinear dependence of energy. With the fixed energy 6uJ and the increasing laser number, the damage degree increases obviously. Furthermore, the electric properties also suffer a certain degradation. Among all the evaluated electric properties, the photoelectric conversion efficiency (η) degraded remarkably.

  4. Particle-on-Film Gap Plasmons on Antireflective ZnO Nanocone Arrays for Molecular-Level Surface-Enhanced Raman Scattering Sensors.

    Science.gov (United States)

    Lee, Youngoh; Lee, Jiwon; Lee, Tae Kyung; Park, Jonghwa; Ha, Minjung; Kwak, Sang Kyu; Ko, Hyunhyub

    2015-12-01

    When semiconducting nanostructures are combined with noble metals, the surface plasmons of the noble metals, in addition to the charge transfer interactions between the semiconductors and noble metals, can be utilized to provide strong surface plasmon effects. Here, we suggest a particle-film plasmonic system in conjunction with tapered ZnO nanowire arrays for ultrasensitive SERS chemical sensors. In this design, the gap plasmons between the metal nanoparticles and the metal films provide significantly improved surface-enhanced Raman spectroscopy (SERS) effects compared to those of interparticle surface plasmons. Furthermore, 3D tapered metal nanostructures with particle-film plasmonic systems enable efficient light trapping and waveguiding effects. To study the effects of various morphologies of ZnO nanostructures on the light trapping and thus the SERS enhancements, we compare the performance of three different ZnO morphologies: ZnO nanocones (NCs), nanonails (NNs), and nanorods (NRs). Finally, we demonstrate that our SERS chemical sensors enable a molecular level of detection capability of benzenethiol (100 zeptomole), rhodamine 6G (10 attomole), and adenine (10 attomole) molecules. This work presents a new design platform based on the 3D antireflective metal/semiconductor heterojunction nanostructures, which will play a critical role in the study of plasmonics and SERS chemical sensors. PMID:26575302

  5. Influence of outgassing organic contamination on the transmittance and laser-induced damage of SiO2 sol-gel antireflection film

    Science.gov (United States)

    Yang, Liang; Xiang, Xia; Miao, Xinxiang; Li, Zhijie; Zhou, Guorui.; Yan, Zhonghua; Yuan, Xiaodong; Zheng, Wanguo; Zu, Xiaotao

    2015-12-01

    The influence of organic contamination (rubber outgassing) on the transmittance of the SiO2 sol-gel antireflection (AR) film and laser-induced damage threshold (LIDT) at 355 nm for 3ω AR film and at 1064 nm for 1ω AR film is studied. The correlation between the contamination time and the transmittance loss/LIDT of 1ω/3ω AR film is also investigated both in atmospheric and vacuum environments. The results show that the transmittance loss increases with increasing contamination time, and the LIDT decreases with increasing contamination time for both in atmospheric and vacuum environments. In addition, the resistance against contamination of the 1ω film is stronger than 3ω film, and the contamination is more serious in vacuum than in an atmosphere environment for the same contamination time. Meanwhile, the damage mechanism is also discussed. It indicated that both the porous structure and photo-thermal absorption contribute to the decreasing LIDT of the sol-gel AR film.

  6. Optimized broad band and quasi-omnidirectional anti-reflection properties with moth-eye structures by low cost replica molding

    International Nuclear Information System (INIS)

    Highlights: • The reflection of only 0.2% has been obtained with silicon moth eyes. • Moth-eye nanostructures have been molded on both rigid glass slide and flexible PET film. • The average reflection of glass slide has achieved 0.4% and remained below 7.5% at 70° incidence from 500 to 1600 nm. - Abstract: Averaged over wavelength range from 500 to 1600 nm at normal incidence, the reflection losses of silicon wafer as master mold are reduced from original 35% to only 0.2% after integrating surface moth-eye structures, and glass slide suppresses the reflection from 7.5% to near 0.4% after incorporating polymer-based moth eyes on double side by replica molding that enables transferring moth eyes from master mold of silicon onto any substrate. An outstanding anti-reflective property out to large incident angles is realized with the average reflection below 0.5% until 50°, below 2.5% at 60° and below 7.5% at 70°, which holds promise for solar cell application

  7. Infrared-induced variation of the magnetic properties of a magnetoplasmonic film with a 3D sub-micron periodic triangular roof-type antireflection structure

    Science.gov (United States)

    Tian, Junlong; Zhang, Wang; Huang, Yiqiao; Liu, Qinglei; Wang, Yuhua; Zhang, Zhijian; Zhang, Di

    2015-01-01

    A carbon-matrix nickel composite magnetoplasmonic film with a 3D sub-micron periodic triangular roof-type antireflection structure (SPTAS) was fabricated via a simple and promising method that combines chemosynthesis with biomimetic techniques. The Troides helena (Linnaeus) forewing (T_FW) was chosen as the biomimetic template. The carbon-matrix Ni wing fabricated via electroless Ni deposition for 6 h (CNMF_6h) exhibits enhanced infrared absorption. Over a wavelength range (888-2500 nm), the enhancement of the infrared absorption of CNMF_6h is up to 1.85 times compared with the T_FW. Furthermore, infrared excitation induces a photothermal effect that results in variation in the magnetic properties of the carbon-matrix Ni wing. The magnetic properties were also confirmed using atomic force microscopy (AFM) and magnetic force microscopy (MFM). The good correlation between the AFM and MFM images demonstrates that the surface of the SPTAS of CNMF_6h exhibits strong magnetic properties. The infrared induced photothermal effect that results in magnetic variation is promising for use in the design of novel magnetoplasmonic films with potential applications in infrared information recording and heat-assisted magnetic recording.

  8. Edison's vacuum coating patents

    International Nuclear Information System (INIS)

    Among the over one thousand patents bearing Thomas A. Edison's name are several for vacuum coating processes including chemical vapor deposition, evaporation, and sputter deposition. Beginning in 1880 Edison applied for patents that described carbon deposition processes that would now be called pyrolytic chemical vapor deposition. In 1884 Edison applied for a patent (granted in 1894) that described coating by evaporation in a vacuum by direct resistance heating or arc heating using a continuous current. Edison called the process 'electro vacuous deposition'. He prophetically wrote, 'the uses of the invention are almost infinite'. Edison also employed sputter deposition and in 1900 applied for a patent on a 'Process of Coating Phonograph Records'. Issued in 1902, the patent describes using a 'silent or brush electrical discharge' produced by an induction coil. The National Phonograph Company, one of Edison's many enterprises, used the sputtering process to deposit a thin layer of gold on wax phonograph cylinder masters that could then be electroplated to form molds to mass produce celluloid duplicates. The method was used for 20 years, from 1901 to 1921. It enabled the reproduction of cylinder grooves less than 0.001 in. deep at a density of 200 grooves per in. From 1913 to 1921, 10-in.-diameter Edison Diamond Disc phonograph records were made using the same method. Sputtering was abandoned in 1927, as it could not be scaled up to produce the 12 in. disks that were then introduced

  9. for zeolite coating

    Directory of Open Access Journals (Sweden)

    Carlos Renato Rambo

    2006-01-01

    Full Text Available Biotemplating is the processing of microcellular ceramics by reproduction of natural morphologies, where the microstructural features of the biotemplate are maintained in the biomorphic ceramic. Different biotemplates with distinct pore anatomies were used to produce biomorphic supports for the zeolite coating: wood, cardboard, sea-sponge and sisal. The biomorphic ceramics were produced by distinguished processing routes: Al-gas infiltration-reaction, liquid-metal infiltration, dip-coating and sol-gel synthesis, in order to produce nitrides, carbides and oxides, depending on the processing conditions. The zeolite coating was performed by hydrothermal growth of MFI-type (Silicalite-1 and ZSM-5 zeolite crystals onto the internal pore walls of the biomorphic templates. The final biomorphic ceramic-zeolite composites were physically characterized, evaluated in terms of their gas adsorption capabilities and correlated to their microstructure and specific pore anatomy. The combination of the properties of the biomorphic ceramics with the adsorption properties of zeolites results in materials with distinct properties as potential candidates for adsorption and catalytic applications due to their characteristic porosity, molecular sieving capabilities and high thermo-mechanical strength.

  10. Surface coating of plastics

    International Nuclear Information System (INIS)

    Electron beam hardening technology has been used mainly for the cross-linking reaction of plastic materials, but recently attention has been paid to the easiness of handling due to the reduction of equipment size and as the countermeasures for preventing atmospheric pollution caused by solvent type paints, Particularly the authors notices the excellent surface properties of electron beam-hardened coatings themselves, and advanced the research and development as one means to give functions to plastic films. In this paper, the transcription foil films having hardness and blur-preventing films are reported. The transcription process for the transcription foils on which hard coating is applied beforehand is shown. The electron beam hardening hard coating was provided next to a supporting film, and its material was polymer or oligomer/polyfunctional monomer/additive. As a primer layer, acrylic polymer was used. The procedure of making transcription foils is explained, and it is important to form uniform, smooth films. If the formation of water drops on surfaces can be prevented, blur does not arise. By heightening the hydrophilicity of material surfaces with electron beam, it may be done. By the selection of the irradiation amount of electron beam and materials, the balance must be maintained. (K.I.)

  11. Coating and curing apparatus and methods

    Energy Technology Data Exchange (ETDEWEB)

    Brophy, Brenor L.; Gonsalves, Peter R.; Maghsoodi, Sina; Colson, Thomas E.; Yang, Yu S.; Abrams, Ze' ev R.

    2016-04-19

    Disclosed is a coating apparatus including flow coating and roll-coating that may be used for uniform sol-gel coating of substrates such as glass, solar panels, windows or part of an electronic display. Also disclosed are methods for substrate preparation, flow coating and roll coating. Lastly, systems and methods for curing sol-gel coatings deposited onto the surface of glass substrates using high temperature air-knives, infrared emitters and direct heat applicators are disclosed.

  12. Coating and curing apparatus and methods

    Science.gov (United States)

    Brophy, Brenor L; Maghsoodi, Sina; Neyman, Patrick J; Gonsalves, Peter R; Hirsch, Jeffrey G; Yang, Yu S

    2015-02-24

    Disclosed are coating apparatus including flow coating and roll-coating that may be used for uniform sol-gel coating of substrates such as glass, solar panels, windows or part of an electronic display. Also disclosed are methods for substrate preparation, flow coating and roll coating. Lastly systems and methods for skin curing sol-gel coatings deposited onto the surface of glass substrates using a high temperature air-knife are disclosed.

  13. High-temperature protective coatings on superalloys

    Institute of Scientific and Technical Information of China (English)

    刘培生; 梁开明; 周宏余

    2002-01-01

    Protective coatings are essential for superalloys to serve as blades of gas turb ines at high temperatures, and they primarily include aluminide coating, MCrAlY overlay coating, thermal barrier coating and microcrystalline coating. In this paper, all these high-temperature coatings are reviewed as well as their preparing techniques. Based on the most application and the main failure way, the importance is then presented for further deepgoing study on the high-temperature oxidation law of aluminide coatings.

  14. Lotus Dust Mitigation Coating and Molecular Adsorber Coating

    Science.gov (United States)

    O'Connor, Kenneth M.; Abraham, Nithin S.

    2015-01-01

    NASA Goddard Space Flight Center has developed two unique coating formulations that will keep surfaces clean and sanitary and contain contaminants.The Lotus Dust Mitigation Coating, modeled after the self-cleaning, water-repellant lotus leaf, disallows buildup of dust, dirt, water, and more on surfaces. This coating, has been successfully tested on painted, aluminum, glass, silica, and some composite surfaces, could aid in keeping medical assets clean.The Molecular Adsorber Coating is a zeolite-based, sprayable molecular adsorber coating, designed to prevent outgassing in materials in vacuums. The coating works well to adsorb volatiles and contaminates in manufacturing and processing, such as in pharmaceutical production. The addition of a biocide would also aid in controlling bacteria levels.

  15. Fabrication of a Ni nano-imprint stamp for an anti-reflective layer using an anodic aluminum oxide template.

    Science.gov (United States)

    Park, Eun-Mi; Lim, Seung-Kyu; Ra, Senug-Hyun; Suh, Su-Jung

    2013-11-01

    Aluminum anodizing can alter pore diameter, density distribution, periodicity and layer thickness in a controlled way. Because of this property, porous type anodic aluminum oxide (AAO) was used as a template for nano-structure fabrication. The alumina layer generated at a constant voltage increased the pore size from 120 nm to 205 nm according to an increasing process time from 60 min to 150 min. The resulting fabricated AAO templates had pore diameters at or less than 200 nm. Ni was sputtered as a conductive layer onto this AAO template and electroplated using DC and pulse power. Comparing these Ni stamps, those generated from electroplating using on/reverse/off pulsing had an ordered pillar array and maintained the AAO template morphology. This stamp was used for nano-imprinting on UV curable resin coated glass wafer. Surface observations via electron microscopy showed that the nano-imprinted patterned had the same shape as the AAO template. A soft mold was subsequently fabricated and nano-imprinted to form a moth-eye structure on the glass wafer. An analysis of the substrate transmittance using UV-VIS/NIR spectroscopy showed that the transmittance of the substrate with the moth-eye structure was 5% greater that the non-patterned substrate. PMID:24245297

  16. Dense protective coatings, methods for their preparation and coated articles

    Energy Technology Data Exchange (ETDEWEB)

    Tulyani, Sonia; Bhatia, Tania; Smeggil, John G.

    2015-12-29

    A method for depositing a protective coating on a complex shaped substrate includes the steps of: (1) dipping a complex shaped substrate into a slurry to form a base coat thereon, the slurry comprising an aqueous solution, at least one refractory metal oxide, and at least one transient fluid additive present in an amount of about 0.1 percent to 10 percent by weight of the slurry; (2) curing the dipped substrate; (3) dipping the substrate into a precursor solution to form a top barrier coat thereon; and (4) heat treating the dipped, cured substrate to form a protective coating.

  17. Nanoparticle/Polymer Nanocomposite Bond Coat or Coating

    Science.gov (United States)

    Miller, Sandi G.

    2011-01-01

    This innovation addresses the problem of coatings (meant to reduce gas permeation) applied to polymer matrix composites spalling off in service due to incompatibility with the polymer matrix. A bond coat/coating has been created that uses chemically functionalized nanoparticles (either clay or graphene) to create a barrier film that bonds well to the matrix resin, and provides an outstanding barrier to gas permeation. There is interest in applying clay nanoparticles as a coating/bond coat to a polymer matrix composite. Often, nanoclays are chemically functionalized with an organic compound intended to facilitate dispersion of the clay in a matrix. That organic modifier generally degrades at the processing temperature of many high-temperature polymers, rendering the clay useless as a nano-additive to high-temperature polymers. However, this innovation includes the use of organic compounds compatible with hightemperature polymer matrix, and is suitable for nanoclay functionalization, the preparation of that clay into a coating/bondcoat for high-temperature polymers, the use of the clay as a coating for composites that do not have a hightemperature requirement, and a comparable approach to the preparation of graphene coatings/bond coats for polymer matrix composites.

  18. Special coatings for the LHC

    CERN Document Server

    Calatroni, S

    2004-01-01

    Several LHC components require a thin film coating. These coatings fall in two main categories, namely NEG coatings to improve the vacuum behaviour of chambers or conductive coatings to decrease the surface impedance of components. Examples of the first category are the intersection vacuum chambers of the different experiments, where the required vacuum can be obtained only with a NEG coating because of the large distance of the nearest pumping station. The graphite jaws of collimators are an example of the second category. In this case the high impedance of graphite must be decreased by a thin copper coating. These and other cases will be illustrated both with respect to the machine requirements and to the production programme.

  19. Article Including Environmental Barrier Coating System

    Science.gov (United States)

    Lee, Kang N. (Inventor)

    2015-01-01

    An enhanced environmental barrier coating for a silicon containing substrate. The enhanced barrier coating may include a bond coat doped with at least one of an alkali metal oxide and an alkali earth metal oxide. The enhanced barrier coating may include a composite mullite bond coat including BSAS and another distinct second phase oxide applied over said surface.

  20. Coatings for fusion reactor environments

    International Nuclear Information System (INIS)

    The internal surfaces of a tokamak fusion reactor control the impurity injection and gas recycling into the fusion plasma. Coating of internal surfaces may provide a desirable and possibly necessary design flexibility for achieving the temperatures, ion densities and containment times necessary for net energy production from fusion reactions to take place. In this paper the reactor environments seen by various componentare reviewed along with possible materials responses. Characteristics of coating-substrate systems, important to fusion applications, are delineated and the present status of coating development for fusion applications is reviewed. Coating development for fusion applications is just beginning and poses a unique and important challenge for materials development