Electro-optics, insulators

The liquid crystalline polymer industry now covers diverse products, from high modulus rope to high strength composite, from the tennis racket to the radial tire cord, from the cover layer of the optical fiber to the microwave oven, from the bullet-proof vest to thermal insulated clothing, and from the electro-optic display to non-linear optical material, etc. 

A material with high electric resistivity is categorized as an insulator material. When we pay attention to their dielectric polarization and apply the materials to the electronics circuits, we usually call them dielectrics . Dielectric ceramics are essential electrical materials for today s advanced electronics devices. Production quantity of the dielectric ceramic is the largest among the other electronics ceramics such as magnetic, semiconductors, insulators, resistors and piezoelectric, and electro-optic materials. Main applications are for ceramic capacitors and microwave resonators. The dielectric ceramics is classified into two groups based on their dielectric properties. 

Raw materials Products Natural clays, SiO, (sand, quartzite) feldspar, anhydrous aluminum silicate, gravel, sand, kalonite Whiteware, concrete, glassee, bricks, abrasives, insulators Prepared powders AI2O3, Si3N4, Z 02, SiC, MgO, B4C3, BaTiO Insulators, lasers, dielectrics, superconductors, substrates, piezoelectronics, magnetics, electro-optics, structural... 

The motivation for this work is in part due to understanding electron-caused discharges along insulating surfaces on spacecraft. It is hoped that Kerr electro-optic field mapping measurements will allow the... 

Carreras, R.F., and Zahn, M., 1986, Kerr electro-optic field mapping measurements in high voltage stressed liquid and gaseous sulfur hexafluoride, "1986 Annual Report for the Conference on Electrical Insulation and Dielectric Phenomena", pp. 287-292. Chandrasekhar, S., 1961, 5 "Hydrodynamic and Hydromagnetic Stability," Oxford Press, London, UK, Chapter 7. 

Zahn, M., and McGuire, T.J., 1980, Polarity effect measurements using the Kerr electro-optic effect with coaxial cylindrical electrodes, IEEE Trans, on Elec. Insul., EI15(3) 287-293. 

Kelley, E.F., and Hebner, R.E., 1986, Electro-optic field measurement at a needle tip and streamer Initiation in nitrobenzene, 1986 Annual Rpt. Conf. Elec. Insul. Dielec. Phen., IEEE 86CH2315-0, pp. 

Cylindrical junctions (i.e., concentric tubules of different materials) should also be possible. For example, consider a nanocapacitor that is 50 nm in diameter and consists of an outer tube of conductive polymer surrounding an inner tube of an insulating plastic (e.g., polystyrene) surrounding a solid nanowire of a second conductive polymer. One of our alumina template membranes (Fig. 16.1C) could contain 10 of these nanocapacitors per square centimeter of membrane area. We have recently prepared such ensembles of nanocapacitor-type devices (74). Analogous ideas will lead to nanobatteries, nano fuel cells and nanoelectronic and electro-optical devices. This next generation of work will be one focus of our research efforts well into the 21st century. 

Poly(methylmethacrylate), PMMA, is soluble in the solvents used for the Durham polyacetylene precursor, so that deposition of the polyacetylene was made first, followed by the PMMA layer. Note that in this case, the insulator/semiconductor interface is made at the tq>, free surface of the polyacetylene, and we can expect that there are differences in the structure of top and the bottom surfaces. We return to this later in connection with the electro-optical properties of the MIS devices in section 6.3. The variation of the differential capacitance with bias voltage for a MIS device built in this way is shown in figure 29. It shows a very similar form to that seen for the other MIS devices, and standard analysis of the capacitance in the depletion regime gives values of Na = 2.1 x 10 6 cm 3 and Vf = -1 V. 

Device motivation for interface studies, and Optical absorption and emission in conjugated oligomers and polymers. The principles of device physics of metal insulator field-effect transistors (MISFETs) and light emitting diodes (LEDs) are oudined mainly as motivation for the contents of the chapters which follow, but also to point out certain features relevant to developing an understanding of the nature of the polymer-metal interface (chapters 5 and 6). The basic principles of electro-luminescence are reviewed here, at the level consistent with the aims of this work. 

For measurements of optical frequencies, ultrafast metal-insulator-metal (MIM) diodes have been developed [235], which can be operated up to 88THz (A = 3.39 Jim). In these diodes, a 25-pm diameter tungsten wire with its end electro-chemically etched to a point less than 200 nm in radius serves as the point contact element, while the optically polished surface of a nickel plate with a thin oxide layer forms the base element of the diode (Fig. 4.99). 

We have shown in section 5.3 that the sub-gap optical absorption of the depletion layo formed in the polyacetylene Schottky diodes shows the removal of the mid-gap soliton states associate with the extrinsic charges present in the undepleted material. The MIS structures operate in both charge accumulation and depletion, and diere is particular int st in the charge accumulation layer in that the charges injected are present without any associated dopant We have therefore carried out an extensive sales of expoiments on the electro-opticd properties of these MIS structures, covering both the electronic excitations of the solitons at mid-gap and also the IR and Raman vibrational excitations of the soliton. All the MIS structures which have been electrically characterised as described in section 6.2 have, been constructed so that they are semitransparent, either over the IR (silicon substrate) or over the IR and visible (polymer insulators, glass substrates). 

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