| 261. |
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| 262. |
- Abadei, S., et al.
(författare)
-
DC field dependent properties of Na0.5 K0.5 NbO3/SiO2/Si structures at millimeter-wave frequencies
- 2001
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 78:13, s. 1900-1902
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Tidskriftsartikel (refereegranskat)abstract
- Dielectric properties of laser-ablated 0.5-μm-thick c-axis epitaxial Na0.5K0.5NbO3 films on high-resistivity (7.7 Ω cm) silicon SiO2/Si substrate are studied experimentally at frequencies up to 40 GHz. For measurements, planar 0.5-μm-thick gold electrodes (interdigital and straight slot) are photolithography defined on the top surface of Na0.5K0.5NbO3 films. The slot width between the electrodes is 2 or 4 μm. 13% capacitance change at 40 V dc bias and Q factor more than 15 are observed at 40 GHz, which makes the structure useful for applications in electrically tunable millimeter-wave devices
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| 263. |
- Abadei, S., et al.
(författare)
-
DC field dependent properties of Na0.5K0.5NbO3/SiO2/Si structures at millimeter-wave frequencies
- 2001
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 78:13, s. 1900-1902
-
Tidskriftsartikel (refereegranskat)abstract
- Dielectric properties of laser-ablated 0.5-mum-thick c-axis epitaxial Na0.5K0.5NbO3 films on high-resistivity (7.7 Omega cm) silicon SiO2/Si substrate are studied experimentally at frequencies up to 40 GHz. For measurements, planar 0.5-mum-thick gold electrodes (interdigital and straight slot) are photolithography defined on the top surface of Na0.5K0.5NbO3 films. The slot width between the electrodes is 2 or 4 mum. 13% capacitance change at 40 V dc bias and Q factor more than 15 are observed at 40 GHz, which makes the structure useful for applications in electrically tunable millimeter-wave devices.
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| 264. |
- Abadei, S., et al.
(författare)
-
Low-frequency and microwave performances of laser-ablated epitaxial Na0.5K0.5NbO3 films on high-resistivity SiO2/Si substrates
- 2002
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 91:4, s. 2267-2276
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Tidskriftsartikel (refereegranskat)abstract
- The dielectric properties of laser-ablated 0.5-mum-thick c-axis epitaxial Na0.5K0.5NbO3 (NKN) films on high-resistivity (>7.7 kOmega cm) silicon SiO2/Si substrates are studied experimentally in the temperature interval of 30-320 K and at frequencies of 1.0 MHz-40 GHz. The films are grown by laser ablation from a stoichiometric target. For the measurements, planar 0.5-mum-thick gold electrodes (interdigital and straight slot) are photolithography defined on the top surface of NKN films. The slot width between the electrodes is 2.0 or 4.0 mum. At low frequencies (f<1.0 GHz), the structure performance is that of a typical metal-dielectric-semiconductor type, where two of this type of capacitor are connected back to back. At these frequencies, the large change in the capacitance (more than 10 times at 1.0 MHz), due to the applied dc field, is mainly due to the changes in depletion layer thickness at the surface of silicon. The associated losses are also large, tan delta>1. At microwave frequencies (f>10 GHz), the voltage dependence of the capacitance is given by the NKN film. More than a 13% capacitance change at 40 V dc bias and a Q factor of more than 15 are observed at 40 GHz, which make the structure useful for applications in electrically tunable millimeter-wave devices.
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| 265. |
- Abadei, Saeed, 1961, et al.
(författare)
-
Low-frequency and microwave performances of laser-ablated epitaxialNa 0.5 K 0.5 NbO 3 films on high-resistivitySiO 2 /Si substrates
- 2002
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 91, s. 2267-
-
Tidskriftsartikel (refereegranskat)abstract
- The dielectric properties of laser-ablated 0.5-μm-thick c-axis epitaxialNa 0.5 K 0.5 NbO 3 (NKN) films on high-resistivity (>7.7 kΩ cm) siliconSiO 2 /Si substrates are studied experimentally in the temperature interval of 30–320 K and at frequencies of 1.0 MHz–40 GHz. The films are grown by laser ablation from a stoichiometric target. For the measurements, planar 0.5-μm-thick gold electrodes (interdigital and straight slot) are photolithography defined on the top surface of NKN films. The slot width between the electrodes is 2.0 or 4.0 μm. At low frequencies(f 1. At microwave frequencies(f>10 GHz), the voltage dependence of the capacitance is given by the NKN film. More than a 13% capacitance change at 40 V dc bias and a Q factor of more than 15 are observed at 40 GHz, which make the structure useful for applications in electrically tunable millimeter-wave devices
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| 266. |
- Abadei, Saeed, 1961, et al.
(författare)
-
Low frequency characterisation of laser ablation deposited thin Na0.5K0.5NbO3 (NKN) films for microwave application
- 2001
-
Ingår i: Integrated Ferroelectrics. - : Informa UK Limited. - 1058-4587 .- 1607-8489. ; 263:1, s. 173-179
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Tidskriftsartikel (refereegranskat)abstract
- Experimental results on three types of Na0.5K0.5NbO3 (NKN) film capacitor structures are presented. The epitaxial NKN thin films have been deposited on (100) Si (high resistivity), SiO2/Si (low resistivity) and Pt/Si (low resistivity) substrates using laser ablation deposition. Both straight slot and interdigital electrode have been deposited on top of the NKN films. The leakage current and low frequency dielectric properties (I-V, C-V, tanδ-V) of the structures have been measured at 1 MHz as a function of electric field at room temperature. In all three types of capacitor structures the leakage currents in a-b plane are very small, while along c-axis there are extremely large leakage currents. On low resistivity silicon substrates the tunability of the dielectric permittivity is about 12% and loss tangent is low also. On high resistivity (ρ>10 kOhm cm) silicon substrate the tunability at 1 MHz is extremely high, about 10 times, and the losses are also high. On the other hand at microwave frequencies the losses are small (tanδ
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| 267. |
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| 268. |
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| 269. |
- Abalo, Ernesto, et al.
(författare)
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Emerging Patterns of Inclusion and Exclusion in the Era of E-government : A Study of Users of ‘Swedish Public Employment Service’ on the Internet
- 2008
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Ingår i: Media and Global Divides. - Stockholm : Organizing Committee for the IAMCR Congress 2008. - 918835430X ; , s. 44-45
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Konferensbidrag (refereegranskat)abstract
- In the area of governmental information for and services to citizens digitalization has certainly become a buzzword. Framed within the discourses on e-government or e-governance – or different mixtures of the two – various analyses have tried to point out, or even anticipate possible consequences of the appropriation of digital technologies, mainly the internet, in governmental services.On the one hand, these analyses have pointed out a great deal of opportunities connected to the incorporation of the internet into governmental information and services. Policy makers have been quick to point to the increased accessibility as a great opportunity for the citizens; in Sweden this vision of accessibility has even been referred to as ‘24:7-governmental agencies’. Academics, among others, have also suggested that the digitalization of information and services opens up new possibilities for citizen control of governments.On the other hand, a number of problems have also been identified. For instance, the digitalization of public registers holding personal information has been interpreted as a threat to the citizens’ integrity: Will digitalization bring a new surveillance society? The most frequently debated problem, however, at least within research, has been the fear of digital divides. Will the internet create digital cleavages between different groups of citizens?So far, however, neither the hopeful nor the dystopian analyses have made enough efforts to critically evaluate their claims. Such evaluations can start from different points of departure, and in this paper the starting point is the citizens as users of governmental information and services through the internet: What patterns of inclusion and exclusion emerge as a governmental agency digitalizes its information and services by making them increasingly internet based?The paper presents statistical data from a survey of 762 unemployed citizens using the Swedish Public Employment Service, a governmental agency that has come to rely specifically heavy on internet based information and service. The initial analysis of data reveals interesting differences between social groups in terms of both perception and use of the internet – in general – and the resources offered by SPES in particular. For instance, the users’ various degrees of education is a strong, determining factor when it comes to use of internet SPES’ services.The paper starts from a conceptual elaboration of various notions of e-government and e-governance. Thereafter, the survey data is described and elaborated on before moving into a discussion of the wider significance of the findings: What does data suggest in terms of patterns of inclusion in and exclusion from a society in which governmental agencies, to an increasing extent, use the internet for their information and services?
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| 270. |
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