Triode

To increase the charge transfer from the polymer to the electrodes, some improvements were made in the device structure. Additional polymer layers were introduced between the PPV layer and electrode [222,223], MEH-PPV was sensitized with Cgo [224], and interpenetrating polymer networks of different PPV derivatives (e.g., MEH-PPV and CN-PPV) [225, 226] or PPV derivatives with other conjugated polymers [227] were used. 

Gain narrowing has been reported for PPV and several PPV derivatives [229] PPV [234] poly(2-butyl-5-(2 -ethylhexyl)-l-4-phenylene vinylene) [230] PPV microcavity [233] PPV with OCgHi7 side groups in the 2,5 positions [232] copolymer of phenylene vinylene [235] poly(dimethylsilane-p-phenylene vinyl-ene)-(2,5-di- -OCtyl-p-phenylene vinylene) [236]. 

In 1994, a polymer-based transistor [237] constructed in a geometry closely related to that of a vacuum tube triode was demonstrated [237]. The structure consists of a thin MEH-PPV polymer film sandwiched between two electrodes, with a third electrode (PANI network) [209, 238-241] embedded within the MEH-PPV film (Fig. 13). This third electrode plays a role similar to that of the grid in a vacuum tube, controlling the current between the two outermost electrodes. Using a generalized analysis based on field-assisted carrier injection by tunneling, the carrier injection and transport in the polymer grid triode could be modeled [242]. 

This Al/MEH-PPV/PANI-network/MEH-PPV/Ca geometry [237] eliminates the relatively long pathways involved in field effect transistors, which constitute a problem considering the low charge carrier mobilities observed in organic materials. As a consequence, a relatively fast response is observed in these device structures. 

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Figure C2.16.9. Schematic cross-section and biasing of a metai-oxide-semiconductor transistor. A unifonn conducting channei is induced between source (S) and drain (D) for > V. Voitage is appiied between the gate (G) and the source. Part (A) shows the channei for - V the transistor acts as a triode. The source-...

Fig. 14. Ionisation gauges (a) triode head and (b) Bayard-Alpert.

Figure 6.15 Circuit symbols and electrical representation of a basic triode or power transistor (BJT)...

A transistor, or n-p-n junction, is built up of two n-type regions of Si separated by a thin layer of weakly p-type (Fig. e). When the emitter is biased by a small voltage in the forward direction and the collector by a larger voltage in the reverse direction, this device acts as a triode amplifier. The relevant energy level diagram is shown schematically in Fig. f... 

The invention of the germanium transistor in 1947 [I, 2] marked the birth of modem microelectronics, a revolution that has profoundly influenced our current way of life. This early device was actually a bipolar transistor, a structure that is mainly used nowadays in amplifiers. However, logical circuits, and particularly microprocessors, preferentially use field-effect transistors (FETs), the concept of which was first proposed by Lilicnficld in 1930 [3], but was not used as a practical application until 1960 [4]. In a FET, the current flowing between two electrodes is controlled by the voltage applied to a third electrode. This operating mode recalls that of the vacuum triode, which was the building block of earlier radio and TV sets, and of the first electronic computers. 

Triode sputteringxxsQS an additional cathode to sustain the plasma but is more complicated and may cause contamination of the deposit. 

Bei alien bis 1948 vorgenommenen Versuchen zur Erreichung niedriger Drucke beobachtete man stets, daB das bekannte Ionisations-manometer (Triode) nie einen tieferen Druck als etwa 10-8 Torr anzeigte. 

Fig. 31 Proposed unimolecular amplifier DiD2A, in a circuit analogous to a grounded-emitter junction transistor, grounded-source FET, or grounded-cathode triode circuit. The arrows show the direction of preferred electron flow. The two Au and one A1 electrode tips must be about 3 nm apart...

The pH, EC and Fe3+ were used as control parameters. The first two were measured with an Orion probe combined pH/ATC electrode Triode and a conductivity cell DuraProbe ref. 0133030. Fe3+ was determined by molecular absorption (thiocyanate method). Mineralogical composition of the precipitates was determined by X-ray powder diffraction (XRD). Scanning electron microscopy, combined with an energy dispersive system (SEM-EDS), allowed the observation of morphological and compositional aspects of the precipitates. 

Tri-O-acylglycerols (TAGs), 70 281 Trioctylphosphine oxide (TOPO), 79 66 Triode gauge, 20 660-661 Triols, phosphine oxide, 77 501 Triorganohydridosilanes, in silicone chemistry, 22 555... 

The field emission display held a particular fascination for this field, because of its potentially large market [36,44-49]. Field emission displays (FEDs) are flat panel displays, which are a flat panel equivalent of the cathode ray tube (CRT), but in which each pixel is addressed by its own electron beam from a field emitter, rather than having a beam scanned across it as in the CRT (Fig. 13.8) [44]. The emitters can be diode or triode type. The triode type is the most elegant, the diode type is lower cost. 

Fig. 13.8 Schematic of a field emission display showing triode system with carbon emitter film.

Fig. 13.9 Schematic diagram of a triode emitter, including electron focusing electrode, for a parallel lithography system.

Fig. 13.10 A triode emitter structure, showing single CNT emitter.

Fig. 13.11 Process path to fabricate the triode emitter structure, showing layer growth, etching, catalyst deposition, and CNT growth steps.

Sputter-ion pumps of the triode type excel in contrast to the diode-type pumps in high-noble gas stability. Argon is pumped stably even at an inlet pressure of 1 10 mbar. The pumps can be started w/ithout difficulties at pressures higher than 1 10 mbar and can operate continuously at an air inlet producing a constant air pressure of 5 10 mbar. A new kind of design for the electrodes extends the service life of the cathodes by 50 %. 

In addition to the conventional ionization gauge, whose electrode structure resembles that of a common triode, there are various ionization vacuum gauge systems (Bayard-Alpert system, Bayard-Alpert system with modulator, extractor system) which more or less suppress the two effects, depending on the design, and are therefore used for measurement in the high and ultrahigh vacuum range. Today the Bayard-Alpert system is usually the standard system. 

A triode of conventional design (see Fig. 3.16 a) is used as the gauge head, but it is slightly modified so that the outer electrode serves as the ion... 

If a triode pump is not needed over an extended period of time it can either... 

Triode ionization vacuum gauge for high vacuum... 

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