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Gourgon C.,Laboratoire Des Technologies Of La Microelectronique Ltm | Philippot G.,CEA Grenoble | Labau S.,Laboratoire Des Technologies Of La Microelectronique Ltm | Tortai J.H.,Laboratoire Des Technologies Of La Microelectronique Ltm | And 2 more authors.
Microelectronic Engineering | Year: 2011

Nanoimprint lithographies (NIL) are very promising for NIL applications on flexible plastic films. In this paper we present some studies and developments of the imprint of polyethylene naphthalate (PEN) films. Different NIL processes are developed successfully; they correspond to the imprint of different chemical phases of the material: semicrystalline, amorphous, and melt. The thermal properties of the film are analyzed, and related to imprint results, which demonstrate that high reproducibility and uniformity are obtained. Moreover, the imprint of such flexible films is much more promising since it avoids NIL limitations commonly observed on semiconductor substrates. © 2011 Elsevier B.V. All rights reserved.

Karst N.,Grenoble Institute of Technology | Rey G.,Grenoble Institute of Technology | Doisneau B.,CNRS Materials Science and Engineering | Roussel H.,Grenoble Institute of Technology | And 5 more authors.
Materials Science and Engineering B: Solid-State Materials for Advanced Technology | Year: 2011

ZnO nanocomposites involving nanowires and nanoparticles with a thickness of 4 μm were grown by chemical bath deposition and used as electron transporting layer in dye-sensitized solar cells (DSSCs). The growth of ZnO nanowires was initially achieved in a zinc nitrate and hexamethylenetetramine aqueous solution on a fluorine-doped tin oxide thin film seeded with ZnO nanoparticles. Subsequently, layered hydroxide zinc acetate (LHZA) nanoparticles were deposited on the nanowires by dip coating in a zinc acetate methanolic solution. A relatively conformal deposit of nanoparticles all along the nanowires was revealed by scanning and transmission electron microscopy. It is shown by X-ray diffraction measurements that a subsequent annealing convert the LHZA nanoparticles into ZnO nanoparticles. The resulting DSSCs present a short circuit current density almost three times higher when the ZnO nanowire interstices were filled with ZnO nanoparticles, which is due to a higher dye loading for a constant device thickness. This is correlated with a very high specific surface area in ZnO nanocomposites, which is 250 times larger than the geometrical surface area. Although a decrease in both the open circuit voltage and the fill factor was shown by electrochemical impedance spectroscopy owing to an increase in electron radiative and nonradiative recombinations, the efficiency of ZnO nanocomposite-based-DSSCs was on average 1.75%, which is 70% higher than for single ZnO nanowire-based-DSSCs. © 2011 Elsevier B.V. All rights reserved.

Pietroy D.,Laboratoire Des Technologies Of La Microelectronique Ltm | Gereige I.,King Abdullah University of Science and Technology | Gourgon C.,Laboratoire Des Technologies Of La Microelectronique Ltm
Microelectronic Engineering | Year: 2013

Nanoimprint Lithography (NIL) is a promising technology for low cost and large scale nanostructure fabrication. This technique is based on a contact molding-demolding process, that can produce number of defects such as incomplete filling, negative patterns, sticking. In this paper, microscopic imaging combined to a specific processing algorithm is used to detect numerically defects in printed patterns. Results obtained for 1D and 2D imprinted gratings with different microscopic image magnifications are presented. Results are independent on the device which captures the image (optical, confocal or electron microscope). The use of numerical images allows the possibility to automate the detection and to compute a statistical analysis of defects. This method provides a fast analysis of printed gratings and could be used to monitor the production of such structures. © 2013 Elsevier B.V. All rights reserved.

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