This work was supported by the Natural Science and Engineering Research Council of Canada (Discovery Grant No. 122795-2010) and the program of the Canada Research Chair in Quantum Semiconductors (JJD). The help provided by Xiaohuan Xuang, Mohamed Walid Hassen and technical assistance of Sonia Blais of the Universit&#233; de Sherbrooke Centre de caract&#233;risation de mat&#233;riaux (CCM) in collecting XPS data are greatly appreciated. NL acknowledges the Merit Scholarship Program for Foreign Student, Fonds de recherche du Qu&#233;bec - Nature et technologies, for providing a graduate student scholarship.

1. Numune Hazırlama <ol><li> (P-katkılı), bir tarafı Si gofreti cilalı bir n-tipi yanlması için bir diamode bir çubuk kullanarak (direncine 3,1 ~ 4,8 Ω.m) çapı 3 inç, 12 mm x 6 mm numuneler halinde, 380 mikron kalınlığında; OptiClear, aseton ve izopropil alkol (her adım için 5 dakika) örnekleri temizleyin. </li><li> 1 dk İlk oksit uzak etch için ~% 0.9 HF çözeltisi içinde aşındırma örnekler; (N2) DI su ile durulayın ve yüksek saflıkta (% 99.999), azot kuru. </li><li> N 2 torbada saklayın hazırlanan numuneler havada kendi oksidasyonu frenlemek için. </li></ol> ArF (λ = 193 nm) ve KrF (λ = 248 nm) Lazerler ile 2. ışın tedavisi Örnekleri. <ol><li> Place 0.74 mm uzunluğunda odasında örnekler ve daha sonra UV yüksek iletim (≥90%) sahip bir erimiş silika pencere ile odasını mühür. H% 0.01-0.2 aralığı içinde ya da gazı giderilmiş Metha 2 O 2 / H2O çözeltisi bölmesini doldurmaknol mikroakışkan kanal kullanılarak. </li><li> Sırasıyla 2.6 ve 1.8 demagnification de homojenize ArF veya KrF lazerler ile örnekleri ışın tedavisi. Dairesel bir maske (çapı 4 mm) ile 100 darbe aşama 600 100&#39;den lazer impulslarından arttırarak her bir numune, sadece 2 mahalline ışın tedavisi. Bir &quot;akçaağaç yaprağı&quot; (9 mm x 7.2 mm) maske ile aynı şekilde örnekleri ışın tedavisi. </li><li> N 2 floş kuru DI suda durulayın örnekleri; daha sonra hızlı bir şekilde daha fazla deney öncesinde havaya maruz kalmasını önlemek amacıyla, N2 ile doldurun, ağzı kapalı bir kap içinde örnekleri yer. </li></ol> 3. Hareketsizleştirme Bio-konjuge nanosferler <ol><li> PH 7,4 fosfat tamponlu tuzlu su (PBS, 1X) oda sıcaklığında 10 12 parçacık / ml solüsyon, biyotin-konjuge ve floresein lekeli 40-mil çaplı nanoküre seyreltin (~ 25 ° C). 2 için ArF veya KrF lazer ışınlanmış örnekler daldırın# 160; oda sıcaklığında, bu çözelti içinde sa. </li><li> PBS ile yıkayın örnekleri yüzeyde fiziksel olarak bağlı floresein lekeli nanokürecikler ortadan kaldırmak için. </li></ol> 4. Yüzey Karakterizasyonu <ol><li> Temas açısı (CA) ölçümü <ol><li> RT ve ortamdaki nem ortamında bir gonyometre ile statik CA ölçümleri yapın. </li><li> Bir mikro şırınga yüksek saflıkta DI su (özdirenç 17.95 M? · Cm) İstihdam; Benzer hacmi oluşturmak (~ 5 ul), her ölçüm için de benzer bir yüksekliğe mikro şırınga düşürerek numune üzerindeki düşer. </li><li> Yakalama ve su yazılımı ile CCD kamera tarafından profil görüntüleri damla kaydedin. Aynı ışınlama şartlarına bağımsız 4 farklı sitelere ölçün. </li><li> Tahmin ve ImageJ yazılım açılan analiz modülü CA değerleri ortalama; resim yüklemek ve gri tonlama içine değiştirmek; eklenti Dropsnake başlatmak; soldan açılan kontür (~ 10 knot) kabaca birkaç knot yerleştirmekSağ yılanı başlatmak için; Bu knot bağlayan eğri kabul ve yılan düğmesine basarak eğriyi gelişmeye. Not: temas açıları görüntü ve tabloda görüntülenir. </li></ol></li><li> XPS ölçümü <ol><li> 150 W çalışan bir Al Ka kaynağı ile donatılmış bir XPS spektrometre (1x10 -9 Torr taban basıncı) ile yüzey kimyasal modifikasyon araştırın: <ol><li> Vakum odasına örnekleri yükleyin. </li><li> 220 mikron x 220 mikron bir alanda 50 eV geçiş enerjisinin sürekli enerji modlarında yüzey araştırması verilerini edinin. </li><li> 20 eV enerji geçmesi aynı analiz alandan yüksek çözünürlüklü taramalar veri elde. </li></ol></li><li> 25,26 başvurulan olarak Süreç, XPS spektrumları ölçümü yazılımı ile spektrumları verileri XPS. </li></ol></li><li> Floresan mikroskop görüntüleme <ol><li> &quot;Akçaağaç yaprağı&quot; maske aracılığıyla ışınlanmış ve lekeli nanokürecikler flourescein maruz kaldıkları örnekleri Excite kullanarakmavi ışık kaynağı (λ = 450 ~ 490 nm). </li><li> 4X büyütme bir floresan ters mikroskop ile, 515 nm&#39;de yayan floresan görüntüleri gözlemleyin. </li><li> 27 başvurulan olarak, AFM ile bu örneklerin yüzey morfolojisi karakterize eder. </li></ol></li></ol>

The authors have nothing to disclose.

Bu yazıda Si-OH üretimine esas olan bir PE kaplama Si yüzey indükleme H2O 2 çözeltinin düşük konsantrasyonda dolu mikro-akışkan odası içinde silisyum UV lazer ışınlamasının bir protokol önermişlerdir. Radikalleri - H 2 O 2 UV, lazer fotoliz negatif yüklü OH oluşturmak gerekiyordu. Ayrıca, UV fotoelektrik etkisi, pozitif yüklü bir yüzey 37 oluşumuna yol açar. Bu nedenle, bu negatif bir OH etkileşimi - pozitif yüklü bir yüzeye sahip k?...

Dikkat çekici elektronik ve kimyasal özellikleri yanı sıra yüksek mekanik mukavemet silikon (Si) mikroelektronik cihazlar ve biyomedikal yongaları 1 için ideal bir seçim yaptık. Si yüzeyin seçici alan kontrolü mikroakışkan ve laboratuvar-on-chip cihazlar 2,3 .Bu genellikle elde ya yüzey sertliği nano ölçekli modifikasyonu ile veya yüzeye 4 kimyasal tedavi ile olan içeren uygulamalar için önemli dikkat çekmiştir. Si yüzeyinde düzensiz ya da düzenli yüzey yapıları üretmek için yüzey pürüzlendirme veya desenlendirme fotolitografi 5, iyon demeti litografi 6 ve lazer teknikleri 7 arasındadır. Bu yöntemler ile karşılaştırıldığında, lazer yüzey dokuma işlemi, yüksek uzaysal çözünürlüğü 8 mikro üretme potansiyeline sahip daha az karmaşık olduğu bildirilmiştir. Ancak, Si darbe akıcılığa karşı olan yüksek bir tekstüre eşiğini gerektiren ışınlama olduğu gibionun ablasyon eşiği (~ 500 mJ / cm 2) 9 aşan yüzey dokusunu neden, Si yüzey tekstüre sıklıkla böyle bir yüksek basınç SF 6 çevre 4,7,8 olduğu gibi reaktif gaz atmosferleri, istihdam yardımcı olmuştur. Sonuç olarak, Si sathının ıslatılabilme kabiliyetinin daha değiştirmek için sayısız çalışmalar 10 organik ve inorganik film 2 biriktirilmesi, ya da plazma ya da elektron ışını yüzey muamelesi 11,12 ile kimyasal muamele üzerine odaklanmıştır. Birkaç dakika 13, 100 ° C de bir H2 O 2 çözeltisi içinde kaynatılarak elde edilebilir yüzeyi üzerinde tek ve ilişkili OH gruplarının varlığından kaynaklanan Si, hidrofilisite kabul edilmektedir. Bununla birlikte, Si-H ya da Si-O-CH3 grupların varlığı nedeniyle, çoğu olan hidrofobik Si yüzey durumları, ışığa 13 HF asit çözeltisi ya da kaplama ile dağlama içeren yaş kimyasal işleme ile elde edilebilir-15. Si ıslanabilirlik seçici alan kontrolü sağlamak için, karmaşık desen adımlar genellikle kimyasal solüsyonlar 16 tedavi de dahil olmak üzere, gereklidir. UV lazer radyasyonunun yüksek kimyasal tepkime de seçici alan süreci, organik film kaplı katı yüzeylerde kullanılan ve onların ıslatılabilirliğini 17 modifiye edilmiştir. Bununla birlikte, sınırlı bir veri miktarı, farklı kimyasal Çözeltilerin bekletilen numunelerin irradyasyonu ile Si ıslanabilirlik lazer destekli modifikasyon mevcuttur. Daha önceki araştırmalarda, hava 18-20 ve NH 3 21 III-V yarı iletkenler UV lazer ışını başarıyla GaAs, InGaAs ve InP yüzey kimyasal bileşimini değiştirmek için kullanılmıştır. Yarı iletken yüzey emdiği suyun, 22 artar ederken deiyonize III-V yarı iletkenlerinin UV içinde lazer kurulan (Dİ) su, yüzey oksitleri ve karbürler azaltır. Bir güçlü hidrofobik Si yüzey (CA ~ 103 °) son çalışma 23 metanol içinde Si örneklerinin ArF lazer ışını ile elde edilmiştir. X-ışını fotoelektron spektroskopisi (XPS) ile gösterildiği gibi, bu temel nedeni CH3 OH photodissociate için ArF lazer yeteneği sağlamaktır. Biz de DI suda H 2 O 2 bir% 0.01 olarak (001) Si ışın tedavisi için kRf ve ArF lazerler kullandım. Bu bize yakın 15 ° CA ile karakterize Si süperhidrofilik yüzeyine (001) selektif alan oluşumunu sağlamak için izin verdi. XPS sonuçları bu ışınlanmış yüzeyi 24 Si-OH bağlarının oluşumuna bağlı olduğunu göstermektedir. H2O 2 / H2O ve metanol solüsyonları düşük konsantrasyonda Si yüzeyinin hidrofilik / hidrofobik yüzey yerinde modifikasyon seçici alanı için kRf ve ArF lazer kullanarak bu tekniğin ayrıntılı bir açıklaması, bu makalede gösterilmiştir. Burada sağlanan ayrıntıları yeterli olmalıdırizin benzer deneyler ilgilenen araştırmacılar tarafından yapılmalıdır.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>fluorescein stained nanospheres</td>
			<td>Invitrogen</td>
			<td>F8795</td>
			<td></td>
		</tr>
		<tr>
			<td>OptiClear</td>
			<td>National Diagnostics</td>
			<td>OE-101</td>
			<td></td>
		</tr>
		<tr>
			<td>ArF laser (&#955;=193 nm)</td>
			<td>Lumonics</td>
			<td>pulse master 800</td>
			<td></td>
		</tr>
		<tr>
			<td>KrF laser (&#955;=248 nm)</td>
			<td>Lumonics</td>
			<td>pulse master 800</td>
			<td></td>
		</tr>
		<tr>
			<td>XPS</td>
			<td>Kratos Analytical</td>
			<td>AXIS Ultra DLD</td>
			<td></td>
		</tr>
		<tr>
			<td>Fluorescence microscope</td>
			<td>Olympus</td>
			<td>IX71</td>
			<td></td>
		</tr>
		<tr>
			<td>XPS quantitification software</td>
			<td>CasaXPS</td>
			<td>2.3.15</td>
			<td></td>
		</tr>
	</tbody>
</table>

selective area modification of silicon surface wettability by pulsed uv laser irradiation in liquid environment

Silikon ıslanabilirlik (Si) biyo-algılayıcı cihazların bu malzeme ve üretim yüzeyi işlevsellik teknolojisinde önemli parametrelerden biridir. Biz Si ​​ıslatımlılık değişiklik yaratmak için orta düşük nabız akıcılıklarda darbe sayısı düşük olan bir sıvı ortamda dalmış Si (001) örnekleri aydınlatarak KrF ve ArF lazerler kullanarak ve işletim bir protokol rapor. Gofret başlangıç ​​temas açısı (CA) ~ 75 ° ölçülebilir değişiklik göstermemiştir bir% 0.01 H 2 O 2 / H 2 O çözeltisi fazla 4 saat dalmış. Ancak, microchamber tür gofret 500 nabız KrF ve ArF lazerler ışınlama% 0.01 H ile dolu 2 2 O çözelti 250 ve 65 mJ / cm 2, sırasıyla, yakın 15 ° CA ​​azalmıştır / H O 2, süperhidrofil bir yüzey oluşumunu göstermektedir. Ince bisküvinin yüzeyi morfolojisinin ölçülebilir bir değişiklik ile OH-grubu, Si (001), oluşumu, varX-ışını fotoelektron spektroskopisi ve atomik kuvvet mikroskopisi ölçümleri ile teyit edilmiştir. Seçici alanı ışınlanmış numuneler daha sonra ışınlanmamış alanda nanoküre başarılı bir immobilizasyon ile sonuçlanan, 2 saat süre ile, bir biyotin-konjuge floresan lekeli nanosferler çözelti içine daldırılmıştır. Bu seçici alan biofunctionalization ve gelişmiş Si tabanlı biyoalgı mimarileri imalatı için yöntemin potansiyelini göstermektedir. Ayrıca 65 mJ darbe akıcılığa çalışan ArF lazer kullanarak metanol (CH3OH), batırılmış gofret ışınlama benzer bir protokol açıklar / cm2 ve 103 CA ile Si (001) arasında güçlü bir hidrofobik yüzey in situ oluşumu °. XPS sonuçları Si ve ArF lazer kaynaklı oluşumunu göstermektedir (OCH3) gözlenen hidrofobisite x bileşikler sorumlu. Ancak, bu tür bileşikler gösteren, metanol içinde KrF lazerle ışınlanan Si yüzeyinde XPS tarafından bulunduKrF lazer yetersizlik metanol photodissociate ve -OCH3 radikalleri oluşturmak için.

Bu temsilci sonuçlar Şekil 1. Bizim daha önce yayınlanmış çalışmaları 23,24 sunulan H farklı konsantrasyonlarda H 2 O DI 250 mJ / cm 2 de KrF lazer tarafından ışınlanmış sitelerde N (darbe sayısı) vs CA gösterir edilmiştir 2 O 2 / H2O çözeltiler (örn., 0.01, 0.02, 0.05, ve% 0.2). CA tüm H 2 O 2 çözümleri için nabız sayısının artması ile azalmaktadır. 0,02 ve% 0.01 H2O 2 ç?...

Watch this Scientific Journal Video about Selective Area Modification of Silicon Surface Wettability by Pulsed UV Laser Irradiation in Liquid Environment at JoVE.com

Selective Area Modification of Silicon Surface Wettability by Pulsed UV Laser Irradiation in Liquid Environment

Biz HF yerinde değişiklik 2 O 2 / H2O çözeltisi (% 0.01% -0.5) ya da metanol solüsyonları H dolu mikroakışkan odaları örnekleri ışınlanması ile hidrofilik veya hidrofobik duruma Si (001) yüzeyi ile tedavi edilmiş bir süreci rapor göreceli düşük nabız akıcılığa darbeli UV lazer kullanarak.

Sıvı Ortamda Darbeli UV Lazer Radyasyonla Silikon Yüzey Islanabilirliği Seçici Alan Değişikliği

The wettability of silicon (Si) is one of the important parameters in the technology of surface functionalization of this material and fabrication of ...

selective-area-modification-silicon-surface-wettability-pulsed-uv

Research

JoVE Journal

Engineering

8.2K Görüntüleme.  Université de Sherbrooke.  Biz HF yerinde değişiklik 2 O 2 / H2O çözeltisi (% 0.01% -0.5) ya da metanol solüsyonları H dolu mikroakışkan odaları örnekleri ışınlanması ile hidrofilik veya hidrofobik duruma Si (001) yüzeyi ile tedavi edilmiş bir süreci rapor göreceli düşük nabız akıcılığa darbeli UV lazer kullanarak. 

Video: Selective Area Modification of Silicon Surface Wettability by Pulsed UV Laser Irradiation in Liquid Environment

Investigation of Early Plasma Evolution Induced by Ultrashort Laser Pulses

Early plasma is generated owing to high intensity laser irradiation of target and the subsequent target material ionization. Its dynamics plays a significant role in laser-material interaction, especially in the air environment1-11.
Early plasma evolution has been captured through pump-probe shadowgraphy1-3 and interferometry1,4-7. However, the studied time frames and applied laser parameter ranges are limited. For example, direct examinations of plasma front locations and electron number densities within a delay time of 100 picosecond (ps) with respect to the laser pulse peak are still very few, especially for the ultrashort pulse of a duration around 100 femtosecond (fs) and a low power density around 1014 W/cm2. Early plasma generated under these conditions has only been captured recently with high temporal and spatial resolutions12. The detailed setup strategy and procedures of this high precision measurement will be illustrated in this paper. The rationale of the measurement is optical pump-probe shadowgraphy: one ultrashort laser pulse is split to a pump pulse and a probe pulse, while the delay time between them can be adjusted by changing their beam path lengths. The pump pulse ablates the target and generates the early plasma, and the probe pulse propagates through the plasma region and detects the non-uniformity of electron number density. In addition, animations are generated using the calculated results from the simulation model of Ref. 12 to illustrate the plasma formation and evolution with a very high resolution (0.04 ~ 1 ps).
Both the experimental method and the simulation method can be applied to a broad range of time frames and laser parameters. These methods can be used to examine the early plasma generated not only from metals, but also from semiconductors and insulators.

An experimental method to examine the early plasma evolution induced by ultrashort laser pulses is described. Using this method, high quality images of early plasma are obtained with high temporal and spatial resolutions. A novel integrated atomistic model is used to simulate and explain the mechanisms of early plasma.

Erken Plazma Evrim Araştırılması ultrashort Lazer Bakliyat Bağlı

Early plasma is generated owing to high intensity laser irradiation of target and the subsequent target material ionization. Its dynamics plays a ...

Mühendislik

Characterization of Surface Modifications by White Light Interferometry: Applications in Ion Sputtering, Laser Ablation, and Tribology Experiments

In materials science and engineering it is often necessary to obtain quantitative measurements of surface topography with micrometer lateral resolution. From the measured surface, 3D topographic maps can be subsequently analyzed using a variety of software packages to extract the information that is needed.
In this article we describe how white light interferometry, and optical profilometry (OP) in general, combined with generic surface analysis software, can be used for materials science and engineering tasks. In this article, a number of applications of white light interferometry for investigation of surface modifications in mass spectrometry, and wear phenomena in tribology and lubrication are demonstrated. We characterize the products of the interaction of semiconductors and metals with energetic ions (sputtering), and laser irradiation (ablation), as well as ex situ measurements of wear of tribological test specimens.
Specifically, we will discuss:
<ol class="lroman">
	<li>Aspects of traditional ion sputtering-based mass spectrometry such as sputtering rates/yields measurements on Si and Cu and subsequent time-to-depth conversion.</li>
	<li>Results of quantitative characterization of the interaction of femtosecond laser irradiation with a semiconductor surface. These results are important for applications such as ablation mass spectrometry, where the quantities of evaporated material can be studied and controlled via pulse duration and energy per pulse. Thus, by determining the crater geometry one can define depth and lateral resolution versus experimental setup conditions.</li>
	<li>Measurements of surface roughness parameters in two dimensions, and quantitative measurements of the surface wear that occur as a result of friction and wear tests.</li>
</ol>
Some inherent drawbacks, possible artifacts, and uncertainty assessments of the white light interferometry approach will be discussed and explained.

White light microscope interferometry is an optical, noncontact and quick method for measuring the topography of surfaces. It is shown how the method can be applied toward mechanical wear analysis, where wear scars on tribological test samples are analyzed; and in materials science to determine ion beam sputtering or laser ablation volumes and depths.

İyon Püskürtme Uygulamaları, Lazer Ablasyon ve Triboloji Deneyler: Beyaz Işık Interferometre ile yüzey modifikasyonları Karakterizasyonu

In materials science and engineering it is often necessary to obtain quantitative measurements of surface topography with micrometer lateral resolution. ...

Fabrication of Nano-engineered Transparent Conducting Oxides by Pulsed Laser Deposition

Nanosecond Pulsed Laser Deposition (PLD) in the presence of a background gas allows the deposition of metal oxides with tunable morphology, structure, density and stoichiometry by a proper control of the plasma plume expansion dynamics. Such versatility can be exploited to produce nanostructured films from compact and dense to nanoporous characterized by a hierarchical assembly of nano-sized clusters. In particular we describe the detailed methodology to fabricate two types of Al-doped ZnO (AZO) films as transparent electrodes in photovoltaic devices: 1) at low O2 pressure, compact films with electrical conductivity and optical transparency close to the state of the art transparent conducting oxides (TCO) can be deposited at room temperature, to be compatible with thermally sensitive materials such as polymers used in organic photovoltaics (OPVs); 2) highly light scattering hierarchical structures resembling a forest of nano-trees are produced at higher pressures. Such structures show high Haze factor (&gt;80%) and may be exploited to enhance the light trapping capability. The method here described for AZO films can be applied to other metal oxides relevant for technological applications such as TiO2, Al2O3, WO3 and Ag4O4.

We describe the experimental method to deposit nanostructured oxide thin films by nanosecond Pulsed Laser Deposition (PLD) in the presence of a background gas. By using this method Al-doped ZnO (AZO) films, from compact to hierarchically structured as nano-tree forests, can be deposited.

Fabrikasyon Pulsed Lazer Biriktirme tarafından Transparent letken Oksitler Nano-mühendislik

Nanosecond Pulsed  Laser Deposition (PLD) in the presence of a background gas allows the deposition  of metal oxides with tunable morphology, structure, ...

Visualization of High Speed Liquid Jet Impaction on a Moving Surface

Two apparatuses for examining liquid jet impingement on a high-speed moving surface are described: an air cannon device (for examining surface speeds between 0 and 25 m/sec) and a spinning disk device (for examining surface speeds between 15 and 100 m/sec). The air cannon linear traverse is a pneumatic energy-powered system that is designed to accelerate a metal rail surface mounted on top of a wooden projectile. A pressurized cylinder fitted with a solenoid valve rapidly releases pressurized air into the barrel, forcing the projectile down the cannon barrel. The projectile travels beneath a spray nozzle, which impinges a liquid jet onto its metal upper surface, and the projectile then hits a stopping mechanism. A camera records the jet impingement, and a pressure transducer records the spray nozzle backpressure. The spinning disk set-up consists of a steel disk that reaches speeds of 500 to 3,000 rpm via a variable frequency drive (VFD) motor. A spray system similar to that of the air cannon generates a liquid jet that impinges onto the spinning disc, and cameras placed at several optical access points record the jet impingement. Video recordings of jet impingement processes are recorded and examined to determine whether the outcome of impingement is splash, splatter, or deposition. The apparatuses are the first that involve the high speed impingement of low-Reynolds-number liquid jets on high speed moving surfaces. In addition to its rail industry applications, the described technique may be used for technical and industrial purposes such as steelmaking and may be relevant to high-speed 3D printing.

Two experimental devices for examining liquid jet impingement on a high-speed moving surface are described: an air cannon device and a spinning disk device. The apparatuses are used to determine optimal approaches to the application of liquid friction modifier (LFM) onto rail tracks for top-of-rail friction control.

Bir Hareketli Yüzeyde Yüksek Hızlı Sıvı Jet birikiminin Görselleştirme

Two apparatuses for examining liquid jet impingement on a high-speed moving surface are described: an air cannon device (for examining surface speeds ...

Integration of Light Trapping Silver Nanostructures in Hydrogenated Microcrystalline Silicon Solar Cells by Transfer Printing

One of the potential applications of metal nanostructures is light trapping in solar cells, where unique optical properties of nanosized metals, commonly known as plasmonic effects, play an important role. Research in this field has, however, been impeded owing to the difficulty of fabricating devices containing the desired functional metal nanostructures. In order to provide a viable strategy to this issue, we herein show a transfer printing-based approach that allows the quick and low-cost integration of designed metal nanostructures with a variety of device architectures, including solar cells. Nanopillar poly(dimethylsiloxane) (PDMS) stamps were fabricated from a commercially available nanohole plastic film as a master mold. On this nanopatterned PDMS stamps, Ag films were deposited, which were then transfer-printed onto block copolymer (binding layer)-coated hydrogenated microcrystalline Si (&#181;c-Si:H) surface to afford ordered Ag nanodisk structures. It was confirmed that the resulting Ag nanodisk-incorporated &#181;c-Si:H solar cells show higher performances compared to a cell without the transfer-printed Ag nanodisks, thanks to plasmonic light trapping effect derived from the Ag nanodisks. Because of the simplicity and versatility, further device application would also be feasible thorough this approach.

A viable transfer printing-based methodology to introduce plasmonic metal nanostructures in solar cells is described. Using nanopillar poly(dimethylsiloxane) stamps, an Ag-based ordered nanodisk array was integrated with standard hydrogenated microcrystalline Si solar cells, which led to improved device performances due to plasmonic light trapping.

Transfer Baskı ile Hidrojene Mikrokristal Silikon Güneş Pilleri Işık Yakalama Gümüş Nanoyapıların Entegrasyonu

One of the potential applications of metal nanostructures is light trapping in solar cells, where unique optical properties of nanosized metals, commonly ...

Automation of Mode Locking in a Nonlinear Polarization Rotation Fiber Laser through Output Polarization Measurements

When a laser is mode-locked, it emits a train of ultra-short pulses at a repetition rate determined by the laser cavity length. This article outlines a new and inexpensive procedure to force mode locking in a pre-adjusted nonlinear polarization rotation fiber laser. This procedure is based on the detection of a sudden change in the output polarization state when mode locking occurs. This change is used to command the alignment of the intra-cavity polarization controller in order to find mode-locking conditions. More specifically, the value of the first Stokes parameter varies when the angle of the polarization controller is swept and, moreover, it undergoes an abrupt variation when the laser enters the mode-locked state. Monitoring this abrupt variation provides a practical easy-to-detect signal that can be used to command the alignment of the polarization controller and drive the laser towards mode locking. This monitoring is achieved by feeding a small portion of the signal to a polarization analyzer measuring the first Stokes parameter. A sudden change in the read out of this parameter from the analyzer will occur when the laser enters the mode-locked state. At this moment, the required angle of the polarization controller is kept fixed. The alignment is completed. This procedure provides an alternate way to existing automating procedures that use equipment such as an optical spectrum analyzer, an RF spectrum analyzer, a photodiode connected to an electronic pulse-counter or a nonlinear detecting scheme based on two-photon absorption or second harmonic generation. It is suitable for lasers mode locked by nonlinear polarization rotation. It is relatively easy to implement, it requires inexpensive means, especially at a wavelength of 1550 nm, and it lowers the production and operation costs incurred in comparison to the above-mentioned techniques.

A protocol to detect and automate mode locking in a pre-adjusted nonlinear polarization rotation fiber laser is presented. The detection of a sudden change in the output polarization state when mode locking occurs is used to command the alignment of an intra-cavity polarization controller in order to find mode-locking conditions.

Çıktı Polarizasyon Ölçümler aracılığıyla Doğrusal Olmayan Polarizasyon Rotasyon Fiber Lazer Mod Kilitleme Otomasyonu

When a laser is mode-locked, it emits a train of ultra-short pulses at a repetition rate determined by the laser cavity length. This article outlines a ...

Emission Spectroscopic Boundary Layer Investigation during Ablative Material Testing in Plasmatron

Ablative Thermal Protection Systems (TPS) allowed the first humans to safely return to Earth from the moon and are still considered as the only solution for future high-speed reentry missions. But despite the advancements made since Apollo, heat flux prediction remains an imperfect science and engineers resort to safety factors to determine the TPS thickness. This goes at the expense of embarked payload, hampering, for example, sample return missions. 
Ground testing in plasma wind-tunnels is currently the only affordable possibility for both material qualification and validation of material response codes. The subsonic 1.2MW Inductively Coupled Plasmatron facility at the von Karman Institute for Fluid Dynamics is able to reproduce a wide range of reentry environments. This protocol describes a procedure for the study of the gas/surface interaction on ablative materials in high enthalpy flows and presents sample results of a non-pyrolyzing, ablating carbon fiber precursor. With this publication, the authors envisage the definition of a standard procedure, facilitating comparison with other laboratories and contributing to ongoing efforts to improve heat shield reliability and reduce design uncertainties.
The described core techniques are non-intrusive methods to track the material recession with a high-speed camera along with the chemistry in the reactive boundary layer, probed by emission spectroscopy. Although optical emission spectroscopy is limited to line-of-sight measurements and is further constrained to electronically excited atoms and molecules, its simplicity and broad applicability still make it the technique of choice for analysis of the reactive boundary layer. Recession of the ablating sample further requires that the distance of the measurement location with respect to the surface is known at all times during the experiment. Calibration of the optical system of the applied three spectrometers allowed quantitative comparison. At the fiber scale, results from a post-test microscopy analysis are presented.

Development of new ablative materials and their numerical modeling requires extensive experimental investigation. This protocol describes procedures for material response characterization in plasma flows with the core techniques being non-intrusive methods to track the material recession along with the chemistry in the reactive boundary layer by emission spectroscopy.

Plazmatronun ablatif Malzeme Test sırasında Emisyon Spektroskopik Sınır Tabaka İncelenmesi

Ablative Thermal Protection Systems (TPS) allowed the first humans to safely return to Earth from the moon and are still considered as the only solution ...

High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia (YSZ) Scaffolds by In Situ Carbon Templating Xerogels

We demonstrate a method for the high temperature fabrication of porous, nanostructured yttria-stabilized-zirconia (YSZ, 8 mol% yttria - 92 mol% zirconia) scaffolds with tunable specific surface areas up to 80 m2&#183;g-1. An aqueous solution of a zirconium salt, yttrium salt, and glucose is mixed with propylene oxide (PO) to form a gel. The gel is dried under ambient conditions to form a xerogel. The xerogel is pressed into pellets and then sintered in an argon atmosphere. During sintering, a YSZ ceramic phase forms and the organic components decompose, leaving behind amorphous carbon. The carbon formed in situ serves as a hard template, preserving a high surface area YSZ nanomorphology at sintering temperature. The carbon is subsequently removed by oxidation in air at low temperature, resulting in a porous, nanostructured YSZ scaffold. The concentration of the carbon template and the final scaffold surface area can be systematically tuned by varying the glucose concentration in the gel synthesis. The carbon template concentration was quantified using thermogravimetric analysis (TGA), the surface area and pore size distribution was determined by physical adsorption measurements, and the morphology was characterized using scanning electron microscopy (SEM). Phase purity and crystallite size was determined using X-ray diffraction (XRD). This fabrication approach provides a novel, flexible platform for realizing unprecedented scaffold surface areas and nanomorphologies for ceramic-based electrochemical energy conversion applications, e.g. solid oxide fuel cell (SOFC) electrodes.

High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia YSZ Scaffolds by In Situ Carbon Templating Xerogels

A protocol for fabricating porous, nanostructured yttria-stabilized-zirconia (YSZ) scaffolds at temperatures between 1,000 &#176;C and 1,400 &#176;C is presented.

tarafından Nano yapılı yitriya stabilize-Zirkonyum (YSZ) iskelelerinin Yüksek Sıcaklık Fabrikasyon<em&gt; Situ</em&gt; Karbon şablonu Kserojeller

We demonstrate a method for the high temperature fabrication of porous, nanostructured yttria-stabilized-zirconia (YSZ, 8 mol% yttria - 92 mol% zirconia) ...

Preparation of Liquid Crystal Networks for Macroscopic Oscillatory Motion Induced by Light

A strategy based on doped liquid crystalline networks is described to create mechanical self-sustained oscillations of plastic films under continuous light irradiation. The photo-excitation of dopants that can quickly dissipate light into heat, coupled with anisotropic thermal expansion and self-shadowing of the film, gives rise to the self-sustained deformation. The oscillations observed are influenced by the dimensions and the modulus of the film, and by the directionality and intensity of the light. The system developed offers applications in energy conversion and harvesting for soft-robotics and automated systems.
The general method described here consists of creating free-standing liquid crystalline films and characterizing the mechanical and thermal effects observed. The molecular alignment is achieved using alignment layers (rubbed polyimide), commonly used in the display manufacturing industry. To obtain actuators with large deformation, the mesogens are aligned and polymerized in a splay/bend configuration, i.e., with the director of the liquid crystals (LCs) going gradually from planar to homeotropic through the film thickness. Upon irradiation, the mechanical and thermal oscillations obtained are monitored with a high-speed camera. The results are further quantified by image analysis using an image processing program.

The goal of the protocol is to create liquid crystalline polymer films that can mechanically oscillate under continuous light irradiation. We describe in great detail the conception of free-standing films, from the liquid crystal alignment method to the photo-actuation. The experimental protocol applied to prepare this material is broadly applicable.

Işık tarafından indüklenen makroskopik salınım hareketi için sıvı kristal ağlar hazırlanması

A strategy based on doped liquid crystalline networks is described to create mechanical self-sustained oscillations of plastic films under continuous ...

Quantitative Analysis of Vacuum Induction Melting by Laser-induced Breakdown Spectroscopy

Vacuum induction melting is a popular method for refining high purity metal and alloys. Traditionally, standard process control in metallurgy involves several steps, include drawing samples, cooling, cutting, transport to the laboratory, and analysis. The whole analysis process requires more than 30 minutes, which hinders on-line process control. Laser-induced breakdown spectroscopy is an excellent on-line analysis method that can satisfy the requirements of vacuum induction melting because it is fast and noncontact and does not require sample preparation. The experimental facility uses a lamp-pumped Q-switched laser to ablate melted liquid steel with an output energy of 80 mJ, a frequency of 5 Hz, a FWHM pulse width of 20 ns, and a working wavelength of 1,064 nm. A multi-channel linear charge coupled device (CCD) spectrometer is used to measure the emission spectrum in real time, with a spectral range from 190 to 600 nm and a resolution of 0.06 nm at a wavelength of 200 nm. The protocol includes several steps: standard alloy sample preparation and an ingredient test, smelting of standard samples and determination of the laser breakdown spectrum, and construction of the elements concentration quantitative analysis curve of each element. To realize the concentration analysis of unknown samples, the spectrum of a sample also needs to be measured and disposed with the same process. The composition of all main elements in the melted alloy can be quantitatively analyzed with an internal standard method. The calibration curve shows that the limit of detection of most metal elements ranges from 20-250 ppm. The concentration of elements, such as Ti, Mo, Nb, V, and Cu, can be lower than 100 ppm, and the concentrations of Cr, Al, Co, Fe, Mn, C, and Si range from 100-200 ppm. The R2 of some calibration curves can exceed 0.94.

During vacuum induction melting, laser-induced breakdown spectroscopy is used to perform real-time quantitative analysis of the main-ingredient elements of a molten alloy.

Lazer kaynaklı arıza spektroskopisi ile vakum Indüksiyon erime niceliksel Analizi

Vacuum induction melting is a popular method for refining high purity metal and alloys. Traditionally, standard process control in metallurgy involves ...