Academic literature on the topic 'Pulsed-NIL'

AbstractPresent investigation is an attempt to study the weldability characteristics of sintered hot-forged plates of AISI 4135 steel produced through powder metallurgy (P/M) route using matching filler materials of ER80S B2. Compacts of homogeneously blended elemental powders corresponding to the above steel were prepared on a universal testing machine (UTM) by taking pre-weighed powder blend with a suitable die, punch and bottom insert assembly. Indigenously developed ceramic coating was applied on the entire surface of the compacts in order to protect them from oxidation during sintering. Sintered preforms were hot forged to flat, approximately rectangular plates, welded by pulsed current gas tungsten arc welding (PCGTAW) processes with aforementioned filler materials. Microstructural, tensile and hardness evaluations revealed that PCGTAW process with low heat input could produce weldments of good quality with almost nil defects. It was established that PCGTAW joints possess improved tensile properties compared to the base metal and it was mainly attributed to lower heat input, resulting in finer fusion zone grains and higher fusion zone hardness. Thus, the present investigation opens a new and demanding field in research.

Indium tin oxide (ITO) thin films were grown on nanopatterned glass substrates by the pulsed laser deposition (PLD) technique. The deposition was carried out at 1.2 J/cm2 laser fluence, low oxygen pressure (1.5 Pa) and on unheated substrate. Arrays of periodic pillars with widths of ~350 nm, heights of ~250 nm, and separation pitches of ~1100 nm were fabricated on glass substrates using UV nanoimprint lithography (UV-NIL), a simple, cost-effective, and high throughput technique used to fabricate nanopatterns on large areas. In order to emphasize the influence of the periodic patterns on the properties of the nanostructured ITO films, this transparent conductive oxide (TCO) was also grown on flat glass substrates. Therefore, the structural, compositional, morphological, optical, and electrical properties of both non-patterned and patterned ITO films were investigated in a comparative manner. The energy dispersive X-ray analysis (EDX) confirms that the ITO films preserve the In2O3:SnO2 weight ratio from the solid ITO target. The SEM and atomic force microscopy (AFM) images prove that the deposited ITO films retain the pattern of the glass substrates. The optical investigations reveal that patterned ITO films present a good optical transmittance. The electrical measurements show that both the non-patterned and patterned ITO films are characterized by a low electrical resistivity (<2.8 × 10−4). However, an improvement in the Hall mobility was achieved in the case of the nanopatterned ITO films, evidencing the potential applications of such nanopatterned TCO films obtained by PLD in photovoltaic and light emitting devices.

The article presents an overview of currently used greenhouse lighting systems. It does not apply to traditional sodium lighting systems, but only to the most modern LEDs. The publication presents descriptions of lamp designs, both foreign and Polish. The aim of the work is not only to review solutions, but also to identify the reasons for the low transfer of scientific and technical solutions to business. There are several barriers to overcome, mainly subjective ones, so that new solutions can be implemented and developed. Full Text: PDF ReferencesS. Ki-Ho, J. Yu-Min, O. Myung-Min, "Application of supplementary white and pulsed light-emitting diodes to lettuce grown in a plant factory with artificial lighting", Springer 57(6), 561 (2016). CrossRef M. Gilewski, "The role of light in the plants world", Phot. Lett. Poland 11, 4 (2019). CrossRef K.J. McCree, Agricultural Meteorology (Elsevier Publishing Company 1972). CrossRef G. Trouwborst, J. Oosterkamp, S. Hogewoning, V. Ieperen, "The application of LEDs as assimilation light source in greenhouse horticulture: A simulation study", the 6th Int. Symposium on Light in Horticulture. Tsukuba. Japan, Nov. 2009. CrossRef K. Jaworski, A. Szmidt-Jaworska, J. Kopcewicz, " Two calcium dependent protein kinases are differently regulated by light and have different activity patterns during seedling growth in Pharbitis nil", Springerlink.com, Journal: 10725, Article: 9609, 2011. CrossRef Philips Lighting, Horticultural LED lighting applications, 2020: https://www.lighting.philips.com/main/products/horticulture. DirectLink E. de Beer, P.H. van Baar, 3 reasons why intercanopy lighting is effective for high-wire vegetables, 2020: www.lighting.philips.com. DirectLink HLG, Refurbished HLG 550, 2020, https://horticulture-lightinggroup.com/collections/lamps/products/refurbished-hlg-550-v1 DirectLink Neonica Polska, 2020, www.growy.eu CrossRef I. Fryc, T. Dimitrova-Grekow, "An automated system for evaluation of the quality of light sources", 6th IEEE Lighting Conference of the Visegrad Countries : LUMEN V4, Sept. 2016. CrossRef EconoLux Ind. Ltd., "What Light do Plants Need", Hong Kong, 2016, http://econoluxindustries.com/light-plants-need.html. DirectLink Heliospectra AB, heliospectra DYNA, 2020, https://www.heliospectra.com/led-grow-lights/dyna. DirectLink Plantlux, Horticulture LED SMD lamp Plantalux XX640W, 2020, https://plantalux.pl/en/plantalux-xx640w-en/. DirectLink M. Gilewski, "An Adaptive and Monoculture Oriented LEDs Lamp", 978-1-5386-7924-1/18/$31.00 ©2018 IEEE, 2018. CrossRef

New Generation Lithographic (NGL) techniques have been recently investigated in order to overcome the limitations of the long-used UV lithography. Several techniques have been proposed during the last decades, but the continued improvement of UV lithography rendered them useful only for a limited number of applications. More recently, nanoimprint lithography (NIL), invented in the nineties, has been considered as the new NGL due to its extreme simplicity and high resolution. Thermal NIL consists in the deformation of a thermoplastic under pressure and temperature by a nanostructured mold, while UV-NIL consists in the polymerization by UV light of a monomer at room temperature and under a lower pressure than Thermal NIL. One of the main problems of this technique is mold-polymer separation after the process. This problem is especially important for UV-NIL, because the working treatments for Thermal NIL degrade with UV light. In order to assess this problem, thin diamond-like amorphous carbon films (DLC) have been proposed as an alternative to existing treatments for their low chemical reactivity and the possibility to incorporate other chemical elements to further reduce their surface energy. Amorphous carbon exists in different forms, depending on how it is grown. Its mechanical properties range from polymer or graphite-like to almost as resistant as diamond. Besides the excellent mechanical properties of DLC (high hardness, elasticity and wear resistance, and low dry friction), amorphous carbon has also been found useful in applications requiring inert and/or biocompatible surfaces. The project DPI2007-61349 of the Science and Innovation Department of Spain, named “Amorphous carbon molds for micro and nanoimprint of polymeric surfaces”, aims to study the effect of the incorporation of different elements in DLC films for the improvement of NIL molds. This thesis has focused on a series of objectives of this project: - Design and construction of a very high vacuum reactor for deposition processes and ionic etch - Incorporation of fluorine to amorphous carbon films and subseqüent characterization by different surface, mechanical and tribological techniques, as well as spectroscopy for the characterization of the plasma used for the process. - Set up and optimization of a deep ion etch technique with ion beam for the production of molds. - The use of different lithographic techniques oriented to the production in large scale of nanometric patterns. - The exploration of mold coating to increase its durability and antisticking properties in nanoimprint processes. The incorporation of fluorine in DLC films has demonstrated to be useful in the improvement of the properties of NIL molds, because it avoids the use of the current surface treatments, which in addition to being less durable, can react with polymers in presence of UV light. In this thesis, the influence of fluorine incorporation in the films has been studied. Fluorinated amorphous carbon films have been deposited by pulsed-DC plasma enhanced chemical vapor deposition, by progressively replacing methane by trifluoromethane. The experimental device used for deposition has been designed and built to allow a number of multiple processes in the same reactor. The results of the study demonstrate the feasibility of this technique, of easy industrial implementation, for the deposition of this type of coatings. The characterization of both the active species in the plasma and the groups incorporated into the deposited films has helped to understand the process of fluorine incorporation, as well as the change in the surface properties that it entails.
La dificultad de extender el uso de la litografía de luz ultravioleta (UV) a los cada vez más estrictos requisitos de resolución, llevaron desde hace ya un par de décadas, a plantearse la necesidad de buscar técnicas litográficas llamadas de “Nueva Generación” (NGL) que las superasen. Son diversas las técnicas se han ido proponiendo durante estos años, pero la mejora de la litografía UV las ha ido relegando fuera del ámbito industrial. Más recientemente, la litografía por nanoestampación (NIL), ha tomado fuerza como la nueva NGL por su extrema sencillez y por su demostrada elevada resolución. La NIL térmica (T-NIL) consiste en la deformación de un termoplástico bajo presión y temperatura por un molde con estructuras nanométricas, mientras que la NIL por UV (UV-NIL) consiste en la polimerización de un monómero a temperatura ambiente con menor presión ejercida por un molde transparente al UV. Uno de los principales problemas de esta técnica es la separación de molde y polímero, una vez finalizado el proceso. Como alternativa a los tratamientos existentes, se han propuesto los recubrimientos de carbono amorfo tipo diamante (DLC) por su baja reactividad química, elevada dureza y posibilidad de incorporación de otros elementos químicos a fin de reducir su energía superficial. El proyecto del Ministerio de Ciencia e Innovación DPI2007-61349, “Moldes de carbono amorfo para micro y nanograbado de superficies poliméricas”, en el cuál se ha enmarcado esta tesis, pretende estudiar los efectos de la incorporación de diferentes elementos en capas de DLC para la mejora de los moldes de NIL. La incorporación de flúor en capas de DLC ha demostrado recientemente ser útil en la mejora de las propiedades de los moldes de NIL, porque evita el uso de los actuales tratamientos superficiales (por ejemplo siloxanos), los cuales, además de ser menos duraderos, pueden reaccionar con los polímeros en presencia de luz UV. Así, en esta tesis se ha estudiado la influencia de la incorporación de flúor a capas de DLC en la composición y en las propiedades de superfície obtenidas.

Transparent conductive oxide (TCO) electrodes are key components in the fabrication of optoelectronic devices such as organic photovoltaic cells (OPVs) or organic emitting devices (OLEDs). Pulsed laser deposition (PLD) results in TCO coatings with adequate optical and electrical properties, the preservation of the target chemical composition in the transferred films being the major advantage of this technique. Furthermore, the performance of the optoelectronic devices can be enhanced by patterning the TCO electrodes. Indium tin oxide (ITO) remains the most popular TCO due to its high conductivity and transparency. The scarcity of the indium resources encouraged the efforts to find an alternative to ITO, a promising candidate being Al-doped ZnO (AZO). Therefore, this chapter is focused on PLD deposition of TCO films (ITO and AZO) on patterned glass substrates prepared by ultraviolet nanoimprint lithography (UV-NIL) for obtaining transparent electrodes with improved characteristics, which further can be integrated in optoelectronic applications.

Nano-imprinting lithography (NIL) has been developed over 15 years and has shown its great potentials for nanopatterning and nano-fabrication. In this paper, new ideas on improving current nano-imprinting methods have been proposed and preliminary experimental tests are carried out. These proposed nano-imprinting methods are all based on the utilization of pulsed laser sources, either in UV or IR region, and can be easily implemented into a roller-based configuration, which is more effective and much faster than conventional planar type nano-imprinting methods. First of all, based on the Laser Assisted Direct Imprinting (LADI) method proposed in 2002, a modified roller-based LADI method is developed by applying a cylindrical quartz roller for mechanically loading as well as for optically focusing of a deep UV laser beam into a line. This modification not only fulfills a continuous type of LADI process but also more efficiently utilizes the laser energy so that large-area LADI is possible. Experimental testing demonstrates an imprinting rate of 3∼10 cm2/min. Secondly, a new nano-imprinting lithography based on pulsed infrared laser heating is proposed and demonstrated. It utilizes the partial transparency of silicon crystals at IR spectrum to heat up the photo-resist layer. Possible improvements and applications on this IR-NIL will be addressed. Finally, a new method of direct contact printing and patterning of a thin metal film on silicon substrate based on the idea of nano-imprinting is presented. This method combines the effects of loaded contact pressure and IR pulsed laser heating at the metal-film/substrate interface to form a stronger bonding between them, and therefore complete the direct pattern transferring of metal film on substrate. Good experimental results are observed and possible applications will be discussed.