Semiconductors, characteristic semiconductor

Considerable interest in the sohd-state physics of sihcon carbide, that is, the relation between its semiconductor characteristics and crystal growth, has resulted from the expectation that SiC would be useflil as a high temperature-resistant semiconductor in devices such as point-contact diodes (148), rectifiers (149), and transistors (150,151) for use at temperatures above those where sihcon or germanium metals fail (see Semiconductors). 

Modulation Spectroscopy has proven to be an important characterization method for semiconductors and semiconductor microstructures. The rich spectra contain a wealth of information about relevant materials, surfaces and interfrces, as well as device characteristics. In general, the apparatus is relatively simple, compact (except EBER), inexpensive (except EBER), and easy to use. One of the main advantages of Modulation Spectroscopy is its ability to perform relevant measurements at room... 

Germanium was the semiconductor material used in the development of the transistor in the early 1950s. However, it exhibits high junction leakage current due to its narrow bandgap and is now largely replaced by silicon. It is a brittle metalloid element with semiconductor characteristics. The properties of germanium are summarized in Table 8.3.1 lP l... 

Figure 4.22 Schematic diagram of a field effect transistor. The silicon-silicon dioxide system exhibits good semiconductor characteristics for use in FETs. The free charge carrier concentration, and hence the conductivity, of silicon can be increased by doping with impurities such as boron. This results in p-type silicon, the p describing the presence of excess positive mobile charges present. Silicon can also be doped with other impurities to form n-type silicon with an excess of negative mobile charges.

It is thus evident that the characteristics of nanocarbons (conductivity, local structure, presence of defects and functional groups, morphology, etc.) are critical to determining the properties of the hybrid nanomaterial with the semiconductor. However, most of the literature studies put emphasis on the analysis of semiconductor characteristics, while often nanocarbons are only described in generic terms (CNT, for example). Yet, it is well known how the properties of nanocarbons can be considerably different from case to case (depending on details in preparation), even if the structure is formally the same (MWCNT, for example). 

Tellurium is a silver-white, brittle crystal with a metallic luster and has semiconductor characteristics. It is a metalloid that shares properties with both metals and nonmetals, and it has some properties similar to selenium and sulfur, located just above it in group 16 of the periodic table. 

The link between chemisorption and semiconductivity, as illustrated by this example, was first clearly perceived by Wagner and Hauffe (2) in 1938. Whereas the production of a semiconductor by chemisorption presents relatively little interest for our purpose, the reverse problem is currently receiving a great deal of attention. How is a given semiconductor going to behave in chemisorption Is it possible to relate semiconductor characteristics with catalytic properties and, if so, what are the properties of the semiconductor that have to be changed in order to modify and control catalytic activity ... 

Substrate Treatment. When the desired image is developed in the resist, the pattern created provides a template for substrate modification. The various chemical and physical modifications currently used can be classified into additive and subtractive treatments. Examples of additive treatments include the insertion of dopants (by either diffusion or ion implantation) to alter the semiconductor characteristics and metal deposition (followed by lift-off or electroplating) to complete a conduction network. In most cases, however, the substrate material is etched by a subtractive process. 

Some of the most important physical characteristics of selenium are its electrical properties. For example, selenium is a semiconductor. A semiconductor is a substance that conducts an electric current better than non-conductors, but not as well as conductors. Semiconductors have many very important applications today in the electronics industry. Selenium is often used in the manufacture of transistors for computers, cellular phones, and hand-held electronic games. 

Fig. 7a. A glass cover plate protects the cell. Sunlight passes through the cover plate and the electrolyte to illuminate the semiconductor surface. Electrical current passes between the semiconductor and the counterelectrode through slots cut in the semiconductor. Characteristic features of this configuration are that no shadows are cast upon the semiconductor and that reaction products could be separated if a membrane were placed between the semiconductor and the counterelectrode.

I-Type Semiconductor - A semiconductor materiai that is left intrinsic, or undoped so that the concentration of charge carriers is characteristic of the materiai itseif rather than of added impurities. 

Conducting properties can also be achieved by reduction of the neutral state. An example is the poly(dibutoxyphenylenevinylene). A platinum electrode coated with polymer in acetonitrile showed the transition between neutral and oxidized state at -r 1V versus a platinum quasi reference electrode and the transition between neutral and reduced state at-1.8 V. The cyclic voltaimnogram is shown in Figure 11.22b as an example to determine characteristic semiconductor properties from cyclic voltammograms. The reduced state has received much less attention than the oxidized state. 

ZnO exhibits many unusual properties including uniaxial piezoelectric response and n-type semiconductor characteristics. 

Since the rate and direction of light-induced charge transfer is governed by the relative position of occupied and unoccupied electronic states in the electrode and the electrolyte, this aspect of semiconductor characteristics of phthalocyanines is reviewed briefly. Knowledge of the position of the highest occupied... 

Polyaniline has been known for more than 100 years. Its semiconductor characteristics as well as possible application as battery electrodes were first... 

Figure 13.3 (a) Schematic comparison of the electronic states of bulk semiconductors and semiconductor NCs. A characteristic bandgap widening is observed for NCs. (b) After exciton generation by light absorption, three basic responses are in principle possible after relaxation via vibrational modes light emission... 

Characteristics Semiconductor Light metal Soft metal Soft metal Soft metal, toxic... 

Intrinsic semiconductor A semiconductor with a degree of purity such that the electrical characteristics... 

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