The Experts below are selected from a list of 2733 Experts worldwide ranked by ideXlab platform
F Faupel - One of the best experts on this subject based on the ideXlab platform.
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tunable polytetrafluoroethylene electret films with extraordinary charge stability synthesized by initiated chemical vapor deposition for organic electronics applications
Scientific Reports, 2019Co-Authors: Stefan Schroder, Thomas Strunskus, Stefan Rehders, Karen K Gleason, F FaupelAbstract:Bulk polytetrafluoroethylene (PTFE) possesses excellent chemical stability and dielectric properties. Indeed, thin films with these same characteristics would be ideal for electret applications. Previously, the electret properties of PTFE-like thin films produced by rf sputtering or plasma enhanced chemical vapor deposition were found to deteriorate due to structural changes and surface oxidation. In this article, the technique of initiated chemical vapor deposition (iCVD) is evaluated for electret applications for the first time. The iCVD method is known for its solvent-free deposition of conformal, pinhole-free polymer thin films in mild process conditions. It is shown that PTFE thin films prepared in this way, show excellent agreement to commercial bulk PTFE with regard to chemical properties and dielectric dissipation factors. After ion irradiation in a corona discharge the iCVD PTFE thin films exhibit stable electret properties, which can be tailored by the process parameters. Due to the mild deposition conditions, the iCVD technique is suitable for deposition on flexible organic substrates for the next-generation electret devices. It is also compatible with state-of-the-art Microelectronic Processing lines due to the characteristics of conformal growth and easy scaling up to larger size substrates.
Stefan Schroder - One of the best experts on this subject based on the ideXlab platform.
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tunable polytetrafluoroethylene electret films with extraordinary charge stability synthesized by initiated chemical vapor deposition for organic electronics applications
Scientific Reports, 2019Co-Authors: Stefan Schroder, Thomas Strunskus, Stefan Rehders, Karen K Gleason, F FaupelAbstract:Bulk polytetrafluoroethylene (PTFE) possesses excellent chemical stability and dielectric properties. Indeed, thin films with these same characteristics would be ideal for electret applications. Previously, the electret properties of PTFE-like thin films produced by rf sputtering or plasma enhanced chemical vapor deposition were found to deteriorate due to structural changes and surface oxidation. In this article, the technique of initiated chemical vapor deposition (iCVD) is evaluated for electret applications for the first time. The iCVD method is known for its solvent-free deposition of conformal, pinhole-free polymer thin films in mild process conditions. It is shown that PTFE thin films prepared in this way, show excellent agreement to commercial bulk PTFE with regard to chemical properties and dielectric dissipation factors. After ion irradiation in a corona discharge the iCVD PTFE thin films exhibit stable electret properties, which can be tailored by the process parameters. Due to the mild deposition conditions, the iCVD technique is suitable for deposition on flexible organic substrates for the next-generation electret devices. It is also compatible with state-of-the-art Microelectronic Processing lines due to the characteristics of conformal growth and easy scaling up to larger size substrates.
Sherif A Elsafty - One of the best experts on this subject based on the ideXlab platform.
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synthesis of mesoporous nio nanosheets for the detection of toxic no2 gas
Chemistry: A European Journal, 2011Co-Authors: Nguyen Duc Hoa, Sherif A ElsaftyAbstract:one of the most highly toxic gases. Humans inhale low-level concentrations of NO2 ( � 50 ppm), which can cause damage to the lungs, cardiovascular system, and upper respiratory tract. Therefore, the Occupational Safety and Health Administration (US) announced that the permissible exposure for general industries is 5 ppm, and 1 ppm for short-term exposure (15 min). The development of gas sensors for monitoring NO2 is highly important and necessary to protect people from over exposure to such dangerous gases and improve environmental quality. Resistive-type gas sensors have been developed for the detection of toxic gases and explosive gases because of their simple design and fabrication, easy read-out signal, on-line monitoring, and high compatibility with Microelectronic Processing. [2] Recently, research is focused on the development of sensing materials with new structures or morphologies to improve sensitivity, selectivity, and stability of sensors. [3] The two-dimensional nanostructure materials, such as graphene, ZnO, and SnO2 nanosheets, have been developed for gas sensor applications because they have excellent properties, such as high crystallinity and high specific surface areas; these attributes enhance the sensitivity and stability of sensing devices. [4] On the other hand, the success in the synthesis of ordered mesoporous materials using a liquid-crystal template has opened a new strategy in their development, especially in gas-sensing applications, in which the high specific surface area of materials is required to improve the sensitivity of
J R Morante - One of the best experts on this subject based on the ideXlab platform.
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tio2 thin films from titanium butoxide synthesis pt addition structural stability Microelectronic Processing and gas sensing properties
Sensors and Actuators B-chemical, 2008Co-Authors: Mauro Epifani, Andreas Helwig, Jordi Arbiol, Raul Diaz, L Francioso, P Siciliano, Gerhard Mueller, J R MoranteAbstract:Abstract TiO 2 thin films were prepared by spin-coating of a Ti butoxide-derived sol onto oxidized silicon wafers, followed by a heat-treatment at temperatures ranging from 500 to 800 °C. The film thickness after heat-treatment at 500 °C was 50 nm. Pt addition, with a Pt:Ti nominal atomic ratio ranging from 0.01 to 0.1, was achieved by adding solutions of Pt(II) acetylacetonate to the TiO 2 sols. The thin films were investigated by X-ray diffraction, evidencing that Pt promoted the structural transformation of the starting anatase phase of TiO 2 to rutile, with a more enhanced effect with increasing the Pt concentration and/or the heat-treatment temperature. High-resolution transmission electron microscopy evidenced that, when a Pt:Ti atomic ratio of 0.05 and a heat treatment at 500 °C were used, the TiO 2 contained both anatase and rutile phases and interspersed Pt nanocrystals (2–3 nm). This result allowed attributing the structural transformation in TiO 2 to the strain created by the Pt nanocrystals—a conclusion which was further corroborated by the observation that Pd-modified films, prepared under similar conditions, were only composed of anatase TiO 2 and did not contain any Pd nanocrystals. The films heat-treated at 500 °C were able to withstand a full Microelectronic Processing sequence, including dry etching for gas sensors sensitive area definition, Ti/Pt contact formation, and heater Processing on the backside of the sensor substrates. H 2 gas-sensing tests evidenced that the anatase TiO 2 phase was much more sensitive than the rutile one. The presence of Pt further enhanced the gas-sensing properties, lowering the optimum sensor operation temperature to about 330 °C and allowing for the detection of a minimum H 2 concentration of about 1000 ppm.
Karen K Gleason - One of the best experts on this subject based on the ideXlab platform.
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tunable polytetrafluoroethylene electret films with extraordinary charge stability synthesized by initiated chemical vapor deposition for organic electronics applications
Scientific Reports, 2019Co-Authors: Stefan Schroder, Thomas Strunskus, Stefan Rehders, Karen K Gleason, F FaupelAbstract:Bulk polytetrafluoroethylene (PTFE) possesses excellent chemical stability and dielectric properties. Indeed, thin films with these same characteristics would be ideal for electret applications. Previously, the electret properties of PTFE-like thin films produced by rf sputtering or plasma enhanced chemical vapor deposition were found to deteriorate due to structural changes and surface oxidation. In this article, the technique of initiated chemical vapor deposition (iCVD) is evaluated for electret applications for the first time. The iCVD method is known for its solvent-free deposition of conformal, pinhole-free polymer thin films in mild process conditions. It is shown that PTFE thin films prepared in this way, show excellent agreement to commercial bulk PTFE with regard to chemical properties and dielectric dissipation factors. After ion irradiation in a corona discharge the iCVD PTFE thin films exhibit stable electret properties, which can be tailored by the process parameters. Due to the mild deposition conditions, the iCVD technique is suitable for deposition on flexible organic substrates for the next-generation electret devices. It is also compatible with state-of-the-art Microelectronic Processing lines due to the characteristics of conformal growth and easy scaling up to larger size substrates.