| 1. |
- Shegai, Timur, 1982, et al.
(författare)
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A bimetallic nanoantenna for directional colour routing
- 2011
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723 .- 2041-1723. ; 2:1
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Tidskriftsartikel (refereegranskat)abstract
- Recent progress in nanophotonics includes demonstrations of meta-materials displaying negative refraction at optical frequencies, directional single photon sources, plasmonic analogies of electromagnetically induced transparency and spectacular Fano resonances. The physics behind these intriguing effects is to a large extent governed by the same single parameter-optical phase. Here we describe a nanophotonic structure built from pairs of closely spaced gold and silver disks that show phase accumulation through material-dependent plasmon resonances. The bimetallic dimers show exotic optical properties, in particular scattering of red and blue light in opposite directions, in spite of being as compact as similar to lambda(3)/100. These spectral and spatial photon-sorting nanodevices can be fabricated on a wafer scale and offer a versatile platform for manipulating optical response through polarization, choice of materials and geometrical parameters, thereby opening possibilities for a wide range of practical applications.
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| 2. |
- Chen, Si, 1982-, et al.
(författare)
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Contacting versus Insulated Gate Electrode for Si Nanoribbon Field-Effect Sensors Operating in Electrolyte
- 2011
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 83:24, s. 9546-9551
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Tidskriftsartikel (refereegranskat)abstract
- Electric response to pH variations is employed to investigate Si nanoribbon field-effect transistors (SiNRFETs) operating in electrolyte with different gate configurations. For devices with a concluding gate electrode for direct metal electrolyte contact, a well-defined electrode reaction leading to a stable electrode potential is essential for retaining a stable electrical potential of the electrolyte. However, noble metals such as Pt do not meet the stability requirement and consequently bring severe distortions to the electronic response. For devices with an insulated gate electrode relying on the principle of capacitive gate coupling, the capacitance between the gate electrode and the electrolyte should be made much larger than the gate capacitance established between the SiNR and the electrolyte. In this case, an efficient gate control as well as a high stability against external disturbances can be ensured. Further studies show that surface charging of the gate insulator is the main cause responsible for the pH response of the SiNRFETs. Hence, devices with different gate configurations give rise to a comparable pH sensitivity.
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| 3. |
- Chen, Si, 1982-
(författare)
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Electronic Sensors Based on Nanostructured Field-Effect Devices
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Point-of-care (POC) diagnostics presents a giant market opportunity with profound societal impact. In particular, specific detection of DNA and protein markers can be essential for early diagnosis of e.g. cancer, cardiovascular disease, infections or allergies. Today, identification of these markers often requires extensive laboratory work and hence is expensive and time consuming. Current methods for recognition and detection of specific biomolecules are mostly optics based and thus impose severe limitations as to convenience, specificity, sensitivity, parallel processing and cost reduction.Electronic sensors based on silicon nanowire field-effect transistors have been reported to be able to detect biomolecules with concentrations down to femtomolar (fM) level with high specificity. Although the reported capability needs further confirmation, the CMOS-compatible fabrication process of such sensors allows for low cost production and high density integration, which are favorable for POC applications. This thesis mainly focuses on the development of a multiplex detection platform based on silicon nanowire field-effect sensors integrated with a microfluidic system for liquid sample delivery. Extensive work was dedicated to developing a top-down fabrication process of the sensors as well as an effective passivation scheme. The operation mechanism and coupling efficiencies of different gate configurations were studied experimentally with the assistance of numerical simulation and equivalent circuits. Using pH sensing as a model system, large effort was devoted to identifying sources for false responses resulting from the instability of the inert-metal gate electrode. In addition, the drift mechanism of the sensor operating in electrolyte was addressed and a calibration model was proposed. Furthermore, protein detection experiments were performed using small-sized Affibody molecules as receptors on the gate insulator to tackle the Debye screening issue. Preliminary results showed that the directionality of the current changes in the sensors was in good agreement with the charge polarities of the proteins. Finally, a graphene-based capacitor was examined as an alternative to the nanowire device for field-effect ion sensing. Our initial attempts showed some attractive features of the capacitor sensor.
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| 4. |
- Fu, C., et al.
(författare)
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Optimization of stiffness for isotropic conductive adhesives
- 2010
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Ingår i: 2010 International Symposium on Advanced Packaging Materials: Microtech, APM '10. - 9781424467563 ; , s. 29-33
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- With the rapid developments of electronic packaging, there is an increasing demand on high performance isotropic conductive adhesives (ICAs). However, the traditional ICAs are brittle, sensitive for crack formation and delamination, which is one of the major drawbacks that limits their use in a wide range of applications. Therefore great efforts have been made to make conductive adhesives more flexible. The present work aims at studying of several chemicals in terms of flexibilizing materials to modify the stiffuess modulus of the conductive adhesives. The effect of the flexibilizers has been characterized by different methods, such as Differential Scanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA), Thermogravimetric Analysis (TGA), etc. Moreover, the electrical resistance, thermal conductivity and viscosity are also measured in various conditions. Experimental results indicate that one of the flexibilizing materials using flexible ester-linkage is particular of interest as it offers low electrical resistance, high thermal performance and low modulus without decreasing glass transition temperature (Tg) and influencing curing and decomposition conditions. ©2010 IEEE.
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| 5. |
- Fu, Yifeng, 1984, et al.
(författare)
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Selective growth of double-walled carbon nanotubes on gold films
- 2012
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Ingår i: Materials Letters. - : Elsevier BV. - 1873-4979 .- 0167-577X. ; 72, s. 78-80
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Tidskriftsartikel (refereegranskat)abstract
- Growth of high-quality vertical aligned carbon nanotube (CNT) structures on silicon supported gold (Au) films by thermal chemical vapor deposition (TCVD) is presented. Transmission electron microscopy (TEM) images show that the growth is highly selective. Statistical study reveals that 79.4% of the as-grown CNTs are double-walled. The CNTs synthesized on Au films are more porous than that synthesized on silicon substrates under the same conditions. Raman spectroscopy and electrical characterization performed on the as-grown double-walled CNTs (DWNTs) indicate that they are competitive with those CNTs grown on silicon substrates. Field emission tests show that closed-ended DWNTs have lower threshold field than those open-ended.
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| 6. |
- Tao, W., et al.
(författare)
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Reliability study for high temperature stable conductive adhesives
- 2010
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Ingår i: 2010 International Symposium on Advanced Packaging Materials: Microtech, APM '10. - 9781424467563 ; , s. 74-77
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- With fast development of electronic packaging, the conductive adhesives were widely used in surface mount and chip interconnection. As an alternative to solder, it has many advantages, such as low processing temperature, less environment contamination and fine pitch capability. However, conductive adhesive joining technology also simultaneously faces a lot of challenges. The major problem of current conductive adhesives is easy to degrade during temperature and humidity aging. Therefore a high temperature stable matrix was developed for conductive adhesive fabrication. Based on this matrix, a kind of isotropic conductive adhesive (ICA) was fabricated in this work. The curing behavior of ICA was investigated by Differential Scanning Calorimeter (DSC). The properties such as glass transition temperature (Tg), storage modulus were detected by Dynamic Mechanical Analyzer (DMA). Thermogravimetric Analysis (TGA) was used to determine the decomposition behavior. The humidity test was subsequently carried out to evaluate moisture resistance of ICA. The electrical resistances of the ICA samples were measured by the multimeter. During humidity test, no obvious change of electrical resistance of ICA samples was observed. ©2010 IEEE.
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