The Triode

The early model for an electron in a metal is shown in Fig. 18.1 and more recently in Fig. 18.2 where is the work function the difference between the energy of an electron in the Fermi level of the metal, Ep and the energy of an electron, Co, outside of the metal  

Roussak and H.D. Gesser, Applied Chemistry A Textbook for Engineers and Technologists, DOI 10.1007/978-l-4614-4262-2 18, Springer Science+Business Media New York 2013 

The semiconductor has been defined in several ways. Two of the most common definitions are based on the limits of two types of measurements (a) electrical resistance with values between 10 and 10 Q cm or 10 and 10 siemens/cm and (b) the energy gap with electronic excite energy between 0 and 3 electron volts (eV). However, some exceptions to these limits do occur. The best known material for the semiconductor is silicon (Si), but many others include naturally occurring minerals such as zinc blende (ZnS), cuprite (CU2O), and galena (PbS). 

A recent award to a company producing semiconductors was made by Global Semiconductor Alliance to SiGe Semiconductor, Inc. in recognition of their efforts in advancing the work on silicon-based RF front-end solutions for wireless connectivity applications in consumer electronics and their lead-free initiative for the industry. 

Recent developments in semiconductors are in the production of photovoltaic devices that convert solar intensity into electrical energy. There are two classes of semiconductors the n- and the p-types. When the doped material releases free electrons, an n-type semiconductor is formed with more electrons than holes. When the reverse occurs, that is, more holes than electrons, then the conduction is a p-type. When these two materials are brought together, they form the p-n junction that favors the flow of electrons in one direction and is referred to as a semiconductor diode. 

---

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. 13.11 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 %. 

Abstract. This work is devoted to development of the effective electron gun for the triode light sources. The electron gun is based on field emission cathode made of a bundle of PAN carbon fibers encapsulated into a glass capillary. The complex of researches on optimization of electron-optical system has been carried out. 

The electron-optical system of the cathodoluminescent lamp consists of electron gun and luminescent screen, which is covered by phosphor. It represents the triode construction. The base of this triode is the cathode-modulator unit (CMU) that consists of field emission cathode and extraction electrode (modulator). 

With this simplification, one can easily estimate the minimum gate width (W) to length (L) ratio required to drive a 1-mm2 pixel element. Such an estimate, for ju = 0.2 cm2 V-1 sec-1, yields W/L = 10 for a FET operating in the triode regime, and 17 for a transistor operating in the saturation regime. 

The transconductance (in siemens) is used as the figure of merit for the triode One wants both a low plate resistance rp and a high amplification factor ji. Of the three triode parameters /i, rp, and gm, only two are independent. 

Because of their fragility and occasional unreliability, the point-contact electrodes were eventually replaced with three layers of adjacent semiconducting surfaces, each of which corresponded to an element in the triode vacuum tube the emitter layer (for the heated filament which is the source of electrons), the base (for the grid that controls the electron flow), and the collector, for the triode plate that receives the electrons. The areas where the layers join one another are called junctions, and transistors made in this way are known as junction transistors. 

The triode detector is a modification of the micro argon detector and a diagram of the triode detector sensor is shown in figure 5. 

The Simple or Macro Argon Detector Sensor The Micro Argon Detector The Triode Detector The Thermal Argon Detector The Helium Detector The Pulsed Helium Discharge Detector The Electron Capture Detector The Pulsed Discharge Electron Capture Detector References Chapter 7... 

An electron source. or electron gun traditionally the most frequent is the triode gun comprising a tungsten wire cathode heated to around 2 700 K. The electrons emitted by the cathode are accelerated by the electric field set up between this negatively polarised filament and the earthed anode. This gun can provide an electron beam of 30 keV with a current density per unit solid angle (also called bright-... 

MOSFETs operating in the triode region can also be used as resistors. Fig. 6.1.12 shows a simplified circuit diagram of a solution used in a surface-microma-... 

Fig. 6.6. A figure showing some of the limitations of determining the threshold voltage through linear extrapolation. In region A, there is significant current flow below the nominal Vr- This is a consequence of slow subthreshold turn-on in the device. Region B shows a non-linear current increase in the triode region of device operation. This type of increase (which can, for example, be caused by field dependent mobility) causes ambiguity in the extrapolated threshold value.

Figure 8-35. Schematic of the triode configuration of PHI for semiconductor implantation.

Polymer grid triode arrays, with four triodes on a single substrate all with a common grid, have been fabricated. The structure of this linear array is shown schematically in Figure 4. The fabrication process for the triode array is similar to that of a single PGT (5, 4) the principal difference is lhat there are separate contact pads for each device in the array. For the arrays fabricated in this initial study, the... 

US engineer Lee De Forest (1873-1961) invents the triode thermionic valve. 

The simplest and still the most widely used electron gun is the triode gun, consisting of a heated filament or cathode, an anode held at a high positive potential relative to the cathode, and, between the two, a control electrode known as the wehnelt. The latter is held at a small negative potential relative to the cathode and serves to define the area of the cathode from which electrons are emitted. The electrons converge to a waist, known as the crossover, which is frequently within the gun itself (Fig. 9). If jc is the current density at the center of this crossover and 0 s is the angular spread (defined in Fig. 9), then... 

Digital electronics got its start in 1906, when American inventor Lee de Forest constructed the triode vacuum tube. Large, slow, and power-hungry as they were, vacuum tubes were nevertheless used to construct the first analogfue and digital electronic computers. In 1947, American physicist William Shockley and colles ues constructed the first semiconductor transistor junction, which quickly developed into more advanced silicon-germanium junction transistors. 

In the rapidly developing field of telecommunications, it became necessary to improve the strength and cjuality of the telegraphic signal. Improvements came with the invention of vacuum tubes. In 1904 the vacuum diode was reported, by J.A. Fleming, and in 1906 De Forest introduced the first triode, which he called "the Audion." The multitude of possibilities of the triode was not grasped by the inventor or his contemporaries until years later. In his paper entitled "The Audion, Its Action and Some Recent Applications," which was read before the Franklin Institute of Philadelphia, January 25, 1920, De Forest stated (IB.) ... 

The triode version of the vacuum tube was soon developed by Lee de Forest, who filed for patent coverage on October 26,... 

The advent of the triode in the communications field via a technology crossover put in the hands of all science a tool of undreamed of worth. Of course, in its early months—and years— its wide range of uses were unrecognized. In his autobiography de Forest (2.1) remarks on it as follows ... 

This new development, the triode, was not immediately used. The first report, some 16 years later, of its use in connection with the hydrogen ion was in the construction of a continuous reading titration apparatus which was published as a paper in the Journal of the American Chemical Society in 1922. It is interesting to note that this research was done for the M.S. degree. Goode stated both in the paper ( 22) and in his thesis (22) ... 

---